Applied Nano doi: 10.3390/applnano7020010

Authors: Victor Idankpo Ameh Ojo Friday Abraham Benjamin Omotayo Adewuyi

Copper functions as an exceptionally efficient conductor, garnering considerable interest in electrical and thermal applications; however, its relatively malleable nature and insufficient durability may hinder its structural effectiveness. This study focused on the development of copper-based nanocomposites by reinforcing a copper matrix with co-precipitated CuO/Al2O3 nanoparticles (varying from 0 to 10 wt% in increments of 2%). A thorough examination was conducted regarding the microstructural characteristics, mechanical properties, and the electrical and thermal conductivities of the composites. X-ray diffraction (XRD) and energy-dispersive spectroscopy (EDS) analysis validated the successful synthesis of nano-sized CuO and Al2O3 phases, with an estimated crystallite size of 33.2 ± 2.4 nm. Scanning electron microscopy revealed a relatively uniform distribution of nano-oxides within the copper matrix, albeit with signs of particle agglomeration at higher loading levels. The durability of the copper exhibited a significant enhancement attributed to the nano-oxide reinforcement, achieving an 180% increase relative to pure copper with a 10% reinforcement addition. Consequently, the tensile strength increased by approximately 68% (from around 154 MPa to nearly 260 MPa), while maintaining an exceptional level of ductility. The electrical conductivity of copper remained largely unchanged with the addition of nanoparticles; rather, a slight improvement in conductivity and a ~30% rise in thermal conductivity were observed at the maximum reinforcement level. This research work presents a copper-based nanocomposite that offers remarkable potential for applications requiring enhanced strength, wear resistance, and exceptional electrical and thermal conductivity.

Applied Nano doi: 10.3390/applnano7010009

Authors: Bora Jeong Myeung-Jin Lee Ho Sung Jang Sunmi Shin Tae-hyung Kim Heesoo Lee Hong-Dae Kim

The commercialization of V-based catalysts for the selective catalytic reduction of NOx by NH3 (NH3-SCR) is hindered by their narrow operating temperature window, insufficient low-temperature (LT) activity, and severe SO2-to-SO3 oxidation. To bridge this gap, we herein introduced Nb and hexagonal BN into a VW/TiO2 system to simultaneously enhance its LT SCR activity, suppress undesired side reactions, and improve durability. Nb incorporation promoted V5+/V4+ redox cycling and enhanced lattice oxygen mobility, thus reducing the apparent activation energy and suppressing SO2 oxidation at elevated temperatures. However, excessive Nb loading induced NH3 oxidation and N2O formation. This drawback was mitigated by introducing BN as a dispersion promoter, which helped secure high catalytic performance at a reduced Nb content. The VWNb/Ti-BN catalyst achieved superior NOx conversion and N2 selectivity over a wide temperature range and benefited from notably suppressed NH3 oxidation and SO2-to-SO3 oxidation. Kinetic analysis revealed that Nb primarily lowered the reaction energy barrier via redox property enhancement, whereas BN accelerated surface reaction turnover by stabilizing and dispersing active acidic sites, markedly increasing the turnover frequency without reducing the activation energy. In situ spectroscopic analysis confirmed the accelerated consumption of adsorbed NH3 species and enhanced formation of reactive NOx intermediates, indicating SCR pathway enhancement. After aging in the presence of SO2 and H2O, the best-performing honeycomb-type monolithic catalyst retained and NOx conversion of >80%, demonstrating excellent long-term durability under practical conditions. A composition-aware machine learning model based on log-ratio-transformed variables quantitatively identified the synergistic balance among V, Nb, W, BN, and TiO2 as the dominant factor governing LT SCR performance. Thus, this work provides valuable mechanistic insights and a strategy for designing wide-temperature-window SCR catalysts with improved activity, selectivity, and resistance to sulfur poisoning.

Applied Nano doi: 10.3390/applnano7010008

Authors: Vyacheslav Alekseevich Moshnikov Ekaterina Nikolaevna Muratova Igor Alfonsovich Vrublevsky Viktor Borisovich Bessonov Stepan Evgenievich Parfenovich Alexandr Ivanovich Maximov Alena Yuryevna Gagarina Danila Andreevich Kavalenka Dmitry Alexandrovich Kozodaev

Currently, titanium dioxide films are widely used as the electron transport layer material in perovskite solar cells. An alternative to titanium dioxide for this role could be niobium pentoxide (Nb2O5), an n-type conducting semiconductor oxide. However, the application of Nb2O5 in perovskite solar cells is hindered by a lack of data on its electron transport properties, electrophysical parameters, and current–voltage characteristics. Amorphous niobium pentoxide films were obtained by magnetron sputtering. To study their electrical and capacitive properties, a structure of heavily doped n+-silicon (n+)/niobium oxide/aluminum was used. Based on the analysis of the I–V curves, it was concluded that for a sample at 25 °C, the electron mean free path is greater than the width of the Schottky barrier layer, allowing electrons to pass through this layer without collisions. At temperatures of 35 °C and higher, electrons experience numerous collisions within the Schottky barrier layer. The height of the Schottky barrier for the contact between niobium pentoxide and aluminum was determined. The obtained capacitance frequency plots were explained using the concepts of dipole-relaxation polarization in a dielectric, where electric dipoles can reorient in an external electric field. It has been shown that the use of magnetron sputtering to produce amorphous niobium pentoxide films leads to a reduction in the effective Schottky barrier height. This allows for high electron injection density at low voltages when using such an oxide semiconductor as an electron transport layer, thereby potentially increasing the efficiency of solar cells.

Applied Nano doi: 10.3390/applnano7010007

Authors: Miaomiao Wang Yuwei Jiang Junjun Tan

Amorphous calcium phosphate (ACP), a key calcium-phosphorus compound, has been widely applied in fields such as dentistry, orthopedics, and biomedicine. However, its potential for removing copper ions from aqueous solutions remains largely unexplored. In this study, sodium citrate-stabilized amorphous calcium phosphate (Cit-ACP) and its calcined derivatives at various temperatures were successfully synthesized as adsorbents for copper ions. The adsorption behavior of Cit-ACP was best described by the Langmuir isotherm, with kinetics following a pseudo-second-order model. Under conditions of pH 5.5 and an initial copper ion concentration of 200 mg/L, Cit-ACP exhibited a maximum adsorption capacity of 323.96 mg/g. Thermodynamic analysis confirmed that the adsorption process was spontaneous and endothermic. Comprehensive characterization via XRD, XPS, and zeta potential measurements before and after adsorption revealed a two-stage adsorption mechanism. At low initial copper concentrations, adsorption occurred predominantly through surface complexation between copper ions and sodium citrate molecules on Cit-ACP nanoparticles. At higher concentrations, the mechanism extended to include co-precipitation of copper ions with hydroxyl groups, which promoted the transformation of Cit-ACP into copper-substituted calcium phosphate phases, such as copper-containing hydroxyapatite. Owing to its straightforward synthesis, high adsorption capacity, and inherent biocompatibility, Cit-ACP presents a promising, cost-effective, and efficient adsorbent for the removal of copper ions from aqueous environments.

Applied Nano doi: 10.3390/applnano7010006

Authors: Gregorio Simon Diaz Martinez Edith Marleny Cadena Chamorro

The utilization of biopolymers as raw materials for the development of sustainable materials has become one of the most promising strategies to minimize the negative impact of plastic pollution. Tubers such as purple yam are rich in starch, which serves as the main component for producing strong and durable bioplastics with properties comparable to conventional plastics. In this study, purple yam flour was used as a raw material to develop a biodegradable film through the casting method. Additionally, Flour Nanoparticles (FN) extracted via the Aqueous Counter Collision technique were incorporated to enhance the mechanical, morphological, and barrier properties of the films. The nanoparticles exhibited sizes below 100 nm, as determined by DLS analysis. The casting process was carried out using film solutions containing 2 wt% flour and 15 wt% glycerol, with FN concentrations of 5 wt%, 15 wt%, and 25 wt%. The main results showed that the films with 25 wt% FN displayed improved mechanical strength, increasing from 2.2 MPa (control) to 7.3 MPa, as well as enhanced thermal resistance, rising from 68 °C (control) to 102 °C. The films also exhibited a smoother morphology, indicating improved water vapor transmission (WVT). The incorporation of FN thus contributed to the development of films with reduced hydrophobicity.

Applied Nano doi: 10.3390/applnano7010005

Authors: Edith Dube Grace Emily Okuthe

Biogenic copper-based nanoparticles have attracted attention as potent antimicrobial agents synthesised via environmentally sustainable routes using plants, microorganisms, and biological waste. Green synthesis leverages phytochemicals, enzymes, and proteins as natural reducing and stabilising agents, enabling nanoparticle formation under mild, non-toxic conditions without hazardous reagents. The resulting nanoparticles are typically spherical, <100 nm in size, and enriched with bioactive surface functionalities that contribute to broad-spectrum antimicrobial activity against bacteria, fungi, and biofilms. Their antimicrobial effects arise from interconnected mechanisms, including the generation of reactive oxygen species, the release of Cu2 ions, membrane disruption, and interference with vital metabolic and genetic processes. Hybrid systems such as Ag–Cu, Zn–CuO, and CuS nanoparticles further enhance efficacy through synergistic redox and photothermal effects. These properties support applications in medical coatings, wound dressings, food packaging, aquaculture disease management, and sustainable crop protection. However, toxicity is highly context-dependent, influenced by factors such as nanoparticle size, shape, surface chemistry, capping agent, concentration, exposure medium, and the biological system. Small or weakly capped NPs can induce cytotoxicity, hemolysis, developmental defects, or growth inhibition, whereas functionalization or capping can improve selectivity and biocompatibility. Standardised physicochemical characterisation, harmonised toxicity testing, and mechanistic understanding are critical for the safe translation of biogenic CuNPs into regulatory-approved applications. This review summarises recent advances (2015–2025) in the biogenic synthesis of copper-based nanoparticles, highlighting how biological systems govern nanoparticle morphology, stability, and antimicrobial efficiency. It integrates mechanistic insights, compares monometallic and hybrid systems, and evaluates emerging applications in medicine, agriculture, aquaculture, and food safety. The review also identifies current limitations and future directions for standardisation, toxicity evaluation, and regulatory approval.

Applied Nano doi: 10.3390/applnano7010004

Authors: Tomohiro Hayashi Glenn Villena Latag Evan Angelo Quimada Mondarte

The interface between synthetic materials and biological systems is a critical determinant of performance in medical devices and biosensors. This review examines the evolution of biointerface science through the lens of self-assembled monolayers (SAMs) of thiols on gold, a model system that offers atomic-level control over surface chemistry. We trace the field from the foundational structural characterization to the establishment of empirical design rules for bio-inertness. While early theoretical models attributed protein resistance to steric repulsion forces in polymer brushes, contemporary understanding has shifted toward the “water barrier” hypothesis, which posits that tightly bound interfacial water prevents direct biomolecular contact. We highlight recent studies that extend these concepts into “realistic” crowded biological environments. Their work reveals that fouling surfaces in crowded media generate a “viscous interphase layer” (VIL) that extends tens of nanometers into solution, whereas zwitterionic surfaces maintain a robust hydration shell that prevents this accumulation. Furthermore, this hydration barrier is shown to fundamentally alter bacterial mechanics, forcing microorganisms into a reversible, tethered “hovering” state at a significant biological interaction distance (>100 nm) from the surface, effectively precluding biofilm nucleation. These insights underscore that the future of antifouling material design lies in the precise engineering of interfacial hydration structures.

Applied Nano doi: 10.3390/applnano7010003

Authors: Md. Shakil Rana Rupna Akther Putul Nanziba Salsabil Maliha Tasnim Kabir Md. Shakhawoat Hossain Shah Md. Masum Md. Ashraful Islam Molla

ZnO semiconductor-based photocatalysts are mainly studied for the elimination of toxic textile dyes. Metal-doped ZnO displays better performance for this purpose. Herein, Al-doped ZnO (Al–ZnO) was prepared using the mechanochemical calcination method with varying aluminum concentrations for the degradation of the persistent methylene blue (MB) dye. Various characterization techniques, including XRD, FTIR, FESEM, TEM, UV-DRS, and XPS, revealed the improved properties of 3% Al–ZnO in degrading the MB dye. It exhibits 96.56% degradation of 25 mg/L MB dye under 60 min of natural sunlight irradiation with a catalyst dose of 0.5 g/L at a natural pH of 6.4. A smaller particle size, a lower band gap energy of 3.264 eV, and the presence of oxygen vacancies and defect states all facilitate photocatalytic degradation. Radical scavenger experiments using ascorbic acid (for •O2−), 2-propanol (for •OH), and diammonium oxalate (for h+) confirmed the crucial role of superoxide (•O2−) and hydroxyl (•OH) radicals in the degradation mechanism. The achievement of 82.80% MB degradation efficiency at the 4th cycle validates the notable stability and excellent reusability of Al–ZnO.

Applied Nano doi: 10.3390/applnano7010002

Authors: Noura El Ghoubali Adnane El Hamidi Amine El Haimeur Khalid Nouneh Abdelkrim Maaroufi

This study aims to address a major challenge and find solutions for developing less expensive, lighter, and more efficient energy storage materials while remaining environmentally friendly. This work combines the study of the structural, morphological, and optical properties of epoxy nanocomposites containing ZnO and SnO2 and highlights the influence of oxide filler content on their energy storage performance. To this end, epoxy nanocomposites filled with metal oxides (ZnO and SnO2) prepared by extrusion, a simple, economical, and reliable industrial method, were studied and compared. The materials obtained are inexpensive, lightweight, and highly efficient, and can replace traditional glass-based systems in the energy sector. The results of XRD, SEM, and FTIR analyses show the absence of impurities, the stability of the structures in humid environments, and the homogeneity of the prepared films. They also indicate that the nature and charge content of the oxide integrated into the polymer matrix play a significant role in the properties of the nanocomposites. Optical measurements were used to determine the film thickness, the type of electronic transition, the band gap energy, and the Urbach energy. Based on the results obtained, the prepared nanocomposite films appear to be promising materials for energy-based optical applications.

Applied Nano doi: 10.3390/applnano7010001

Authors: Marwa Mohammad Duaa Abuarqoub Mohammad Alnatour Abdolelah Jaradat Nidal A. Qinna Ghayda’ AlDabet Alqassem H. Abuarqoub Abdalla Awidi

Objectives: This study aimed to optimize WS6-loaded nanoparticles (NPs) with favorable therapeutic properties, including appropriate size, low toxicity, high encapsulation efficiency, and enhanced biocompatibility, for selective cancer targeting and regenerative applications. Methods: Three formulations were investigated: solid lipid nanoparticles (SLNs), polycaprolactone (PCL)-based NPs, and Eudragit RS100-based NPs via microfluidic synthesis. Their physicochemical properties were assessed, followed by biological evaluation on normal cells—dental-derived stem cells (DSCs), gingival fibroblasts (GFs), and human dermal fibroblasts (HDFs)—and cancer cell lines MDA-231 and HepG2. Assays included MTT for viability, apoptosis/necrosis, cell cycle analysis, ROS detection, and cytokine profiling. Results: SLNs showed inherent toxicity despite improved viability upon WS6 loading. PCL NPs improved encapsulation and compatibility but lacked stability. The microfluidic RS-WS6 NPs exhibited optimal characteristics, significantly enhancing viability in normal cells and selectively inducing apoptosis in cancer cells. At 1 µM, RS-WS6 NPs reduced ROS in normal cells (p < 0.05) and increased it in cancer cells (p < 0.05). Cytokine analysis revealed significant downregulation of IL-6, IL-12p70, and TNF-α (p < 0.05), indicating immunomodulatory potential. Conclusions: RS-WS6 NPs developed via microfluidics offer a promising therapeutic platform with selective cytotoxicity against cancer cells, minimal toxicity to normal cells, and anti-inflammatory properties, supporting their use in targeted therapy and regenerative medicine.

Applied Nano doi: 10.3390/applnano6040030

Authors: Mathis Janßen Anastasiia D. Murkina Julia Hann Gunnar Klös Martin Moebius Christoph R. Meinecke Andreas Morschhauser Aitziber L. Cortajarena Danny Reuter

Since the introduction of the DNA origami technology by Seeman and Rothemund, the integration of functional entities (nanoparticles, quantum dots, antibodies, etc.) has been of huge interest to broaden the area of applications for this technology. The possibility of precise functionalization of the DNA origami technology gives opportunity to build up complex novel structures, opening up endless opportunities in medicine, nanotechnology, photonics and many more. The main advantage of the DNA origami technology, namely the self-assembly mechanism, can represent a challenge in the construction of complex mixed-material structures. Commonly, DNA origami structures are purified post-assembly by filtration (either spin columns or membranes) to wash away excess staple strands. However, this purification step can be critical since these functionalized DNA origami structures tend to agglomerate during purification. Therefore, custom production and purification procedures need to be applied to produce purified functionalized DNA origami structures. In this paper, we present a workflow to produce functionalized DNA origami structures, as well as a method to qualify the successful hybridization of a quantum dot to a square frame DNA origami structure. Through the utilization of a FRET fluorophore–quencher pair as well as a subsequent assembly, successful hybridization can be performed and confirmed using photoluminescence measurements.

Applied Nano doi: 10.3390/applnano6040029

Authors: Sonia Ceron David Barba Miguel A. Dominguez

In this work, an eco-friendly 3D screen printing technique implemented in roll-to-roll technology for the manufacturing of flexible electronics is presented. The conductive ink was prepared through the decomposition of hydrogen peroxide, an eco-friendly reagent, onto the surfaces of silver nanoparticles. A biodegradable master pattern for screen printing was printed by 3D fused deposition modeling using a polylactic acid filament. This technique was implemented to fabricate hybrid touch-sensitive sensors, to be used as electrical switches, on both photographic and conventional office papers. The functionality of these sensors was demonstrated, and the systems were tested under aging and bending conditions, proving the reliability of this technological approach in flexible electronics and offering a biodegradable alternative.

Applied Nano doi: 10.3390/applnano6040028

Authors: Luiz Eduardo Nochi Castro William Gustavo Sganzerla Carina Mendonça Müller Lázaro José Gasparrini Helton José Alves Dirlei Diedrich Kieling Cassia Reika Takabayashi Leda Maria Saragiotto Colpini

The growing demand for environmentally friendly materials has driven extensive research into biopolymer-based nanocomposites with enhanced functional performance. Chitosan, a naturally derived polysaccharide, offers excellent film-forming ability, biodegradability, and antimicrobial potential, making it a promising matrix for sustainable packaging and coating applications. In this study, a distinctive solvent-casting strategy was employed to fabricate chitosan-based nanocomposite films functionalized with dual-action silver/titania (Ag/TiO2) nanoparticles, combining both photocatalytic and metallic antimicrobial mechanisms—an approach that provides broader functionality than conventional single-component fillers. The biodegradable films were systematically characterized for their structural, mechanical, optical, and barrier properties, as well as their antimicrobial performance. The integration of Ag/TiO2 imparted unique synergistic effects, modifying film morphology and color, slightly reducing tensile strength, and enhancing hydrophobicity and structural compactness. The obtained water vapor permeability values (0.013–0.102 g·mm·m−2·h−1·kPa−1) classified the materials as moderate barriers, comparable to or better than many existing chitosan-based systems without nanofiller reinforcement. Notably, films containing 10 wt% Ag/TiO2 achieved a 40.4% reduction in Escherichia coli viability and an 8.2% inhibition of Staphylococcus aureus, demonstrating concentration-dependent antimicrobial activity superior to that of neat chitosan films. Overall, the unique combination of a biodegradable chitosan matrix with multifunctional Ag/TiO2 nanofillers offers clear advantages over traditional biopolymer films, highlighting their potential as advanced materials for active food packaging and antimicrobial surface coatings.

Applied Nano doi: 10.3390/applnano6040027

Authors: Marita Wulandari Santanu Saha Yasuhisa Adachi

Ultrafine bubbles (UFBs) have been proposed as interfacial agents that modulate colloidal interactions, yet their role in early-stage flocculation remains insufficiently quantified. Using amidine latex (AL) as a cationic model colloid under controlled end-over-end mixing, we combined flocculation kinetics with electrokinetic and interfacial measurements to elucidate the mechanism by which UFBs promote aggregation. Electrophoretic measurements show adsorption-driven charge regulation by bubbles; increasing the UFB-to-AL ratio progressively neutralizes the surface and at sufficient dose reverses its charge. The neutrality point occurs at a characteristic ratio that is only weakly sensitive to background sodium chloride (NaCl). Interfacial measurements reveal a thicker hydrodynamic layer at higher ionic strength, consistent with closer packing of adsorbed UFBs under double layer compression, and micrographs of particle dimers confirm a larger inter-particle separation that directly visualizes this layer. Aggregation accelerates at 10 mM sodium chloride but remains slow at 0.1 mM, indicating that electrolyte screening is required for efficient adsorption and bridging; pH modulated the process secondarily. Together, the results support a coherent picture in which UFB adsorption creates patchy, charge-compensated surfaces and a soft hydrodynamic layer that enlarges the effective collision cross-section, thereby enhancing early-stage flocculation.

Applied Nano doi: 10.3390/applnano6040026

Authors: Thanee Jaiyan Paweena Rangsrisak Kanchit Rahaeng Duagkamol Maensiri Wuttipong Mahakham

Bacterial leaf blight (BLB), a destructive disease of rice caused by Xanthomonas oryzae pv. oryzae (Xoo), continues to limit rice productivity worldwide. Although biologically synthesized zinc oxide nanoparticles (ZnO NPs) have been extensively investigated, knowledge regarding the antibacterial activity and biocompatibility of commercially available ZnO NPs is still limited. In this study, commercial ZnO NPs were systematically characterized and evaluated for their antibacterial mechanisms and biocompatibility in mammalian cells. FE-SEM and TEM analyses revealed irregular polyhedral, hexagonal, and short rod-like morphologies with an average particle size of ~33 nm, consistent with crystallite sizes estimated by XRD. The nanoparticles exhibited pronounced antibacterial activity against Xoo, with a minimum inhibitory concentration (MIC) of 16 µg/mL and a clear dose-dependent response. Mechanistic assays confirmed multifaceted bactericidal actions involving membrane disruption, ROS generation, Zn2+ release, and ultrastructural damage. Biocompatibility testing in human dermal fibroblasts showed enhanced proliferation at 8–32 µg/mL, no cytotoxicity up to 256 µg/mL, and reduced viability only at ≥512 µg/mL. These findings represent the first mechanistic evaluation of commercial ZnO NPs against Xoo, together with cytotoxicity assessment in mammalian cells, highlighting their structural distinctness and dual functionality that combine potent antibacterial activity with minimal mammalian cytotoxicity. Overall, the results underscore their potential as safe nanobiocontrol agents for sustainable rice disease management.

Applied Nano doi: 10.3390/applnano6040025

Authors: James Bolton Susana Gomez Alessandro Nardecchia Eva M. Torres Laura Rodriguez-Turienzo

An industrial system, based on a probe for turbidity measurement and a model, has been developed and tested for the in-line monitoring of nanoparticle synthesis reactions, thus providing information on the reaction progress and particle size. Real-time turbidity measurements, reliably indicating the reaction end and allowing run-time variations to be detected, were obtained for three silica nanoparticle syntheses. The system, initially built for a research laboratory reactor of 6 L, was successfully upscaled to an industrial 160 L reactor, simply by adapting the probe’s mounting components. In a further upscaling process, transferability of the model from the smaller to the larger reactor, giving accurate particle size predictions, was achieved. In addition, a combined model, developed from the first two reactions, predicted the particle size in the third reaction without first needing to obtain any data for the model from this reaction. The combined model’s predictions showed an average relative error of 18% with respect to the measured particle size. The probe was resistant to harsh reaction conditions at a temperature of 90 °C with concentrated acids, making the system potentially useful in industrial nanoparticle production.

Applied Nano doi: 10.3390/applnano6040024

Authors: Angelo Taglietti

When I was first invited to lead the Editorial Board of Applied Nano in 2020, one question immediately came to mind: Do we really need another nano-journal [...]

Applied Nano doi: 10.3390/applnano6040023

Authors: Yuliya Ermakova Ekaterina Dmitrieva Irina Gracheva Darya Shurtakova Margarita Sadovnikova Fadis Murzakhanov Georgy Mamin Sergey Nagalyuk Evgeny Mokhov Marat Gafurov

Solid-state spin centers are at the forefront of developing advanced quantum technologies, engaging in applications of sensing, communication and computing. A semiconductor host matrix compatible with existing silicon technology provides a robust platform for holding spin defects and an opportunity for external manipulation. In this article, negatively charged nitrogen-vacancy (NV) centers in the hexagonal hh position in a 6H polytype silicon carbide crystal was studied using high-frequency (94 GHz) electron paramagnetic (EPR) and electron nuclear double resonances (ENDOR) spectroscopy. Experimentally determined values of hyperfine and quadrupole interactions of 14N were compared with the values obtained for the centers in NVk2k1 positions. The distribution of spin density of the defect within a supercell of the SiC crystal lattice was calculated using the density functional theory approach. The theoretical estimation of electron-nuclear interaction constants turned out to be in close agreement with the experimental values, which allows us to refine the microscopic model of a point defect. The temperature dependence of the spin Hamiltonian values (δA/δT ≅ 180 Hz/K) was studied with the possibility of observing the 14N NMR signal at room temperature. The fundamental knowledge gained about interactions’ parameters’ behavior lays the foundation for the creation of promising quantum platforms.

Applied Nano doi: 10.3390/applnano6040022

Authors: Oksana Velgosova Lívia Mačák Maksym Lisnichuk Peter Varga

The synthesis of silver nanoparticles (AgNPs) using sustainable and non-toxic methods has become an important research focus due to the limitations of conventional chemical approaches, which often involve hazardous reagents and produce unstable products. In particular, the effects of reaction conditions on the quality and stability of AgNPs obtained via green synthesis remain insufficiently understood. This study addresses this gap by examining the influence of pH and temperature on the synthesis of AgNPs using Rosmarinus officinalis extract as both reducing and stabilizing agents. UV-vis spectroscopy and TEM analysis revealed that optimal conditions for producing uniform, stable, and spherical AgNPs were achieved at pH 8, with a narrow size distribution (~17.5 nm). At extreme pH values (≤3 or ≥13), nanoparticle formation was hindered by aggregation or precipitation, while elevated temperatures mainly accelerated reaction without altering particle morphology. HRTEM and SAED confirmed the crystalline face-centered cubic structure, and colloids synthesized at pH 8 showed excellent stability over 30 days. Overall, the results demonstrate that precise pH control is critical for obtaining high-quality AgNPs via a simple, scalable, and environmentally friendly approach. Their stability and homogeneous size highlight potential applications in biomedicine, food packaging, and sensing, where reproducibility and long-term functionality are essential.

Applied Nano doi: 10.3390/applnano6040021

Authors: Lok R. Pokhrel Caroline A. Knowles Pradnya T. Akula

Nano-sanitizers, which exploit the unique physicochemical properties of nanomaterials, are being increasingly investigated as innovative tools to promote food safety. In this argumentative review, we compare and contrast nano-sanitizers with conventional sanitation methods by examining their underlying antimicrobial mechanisms, multifaceted benefits, inherent challenges, and wide-ranging public health implications. We evaluate regulatory conundrums and consumer perspectives alongside future outlooks for integration with advanced technologies such as artificial intelligence. Through selective synthesis of the published literature, our argumentative discussion demonstrates that nano-sanitizers not only promise superior performance in pathogen inactivation but could also contribute to overall food system sustainability, provided safety and regulatory concerns are adequately addressed.

Applied Nano doi: 10.3390/applnano6040020

Authors: Sahari Inoue Binyam Tedla Jean-Marie Sobze Raymond Thomas

Seedling establishment on reclaimed boreal sites is frequently constrained by drought and other abiotic stresses. Carbon nanomaterials have been shown to influence stress physiology in crops, but their effects on native boreal species are poorly understood. We tested whether carboxylic acid-functionalized multi-walled carbon nanotubes (MWCNTs) alter drought responses in three shrubs widely used in reclamation: Shepherdia canadensis (L.) Nutt, Cornus sericea L., and Viburnum edule. Seedlings received two irrigations with MWCNTs suspensions (0 (control), 10, or 30 mg L−1) before exposure to well-watered or drought conditions in a greenhouse. Drought reduced photosynthesis, stomatal conductance, and transpiration and increased Ci/Ca across species, consistent with declining leaf water potential. MWCNTs did not broadly modify these responses, but the highest concentration (30 mg L−1) further suppressed stomatal conductance in C. sericea and V. edule during mid- to late drought. S. canadensis showed little responsiveness. These effects suggest that MWCNT-associated stomatal closure may limit water loss under stress but also constrain CO2 uptake, offering no clear photosynthetic benefit. MWCNT impacts were subtle, species- and dose-dependent, and centered on stomatal regulation. Application in reclamation should therefore be approached cautiously, balancing potential water-saving benefits against possible reductions in carbon assimilation and growth.

Applied Nano doi: 10.3390/applnano6030019

Authors: Valeria De Matteis Cristina Baglivo Silvia Tamborino Mariafrancesca Cascione Marco Anni Paolo Vitali Giuseppe Negro Mariaenrica Frigione Paolo Maria Congedo Rosaria Rinaldi

Carbon dots (CDs) derived from renewable biomass are emerging as sustainable alternatives to traditional nanomaterials for applications in bioimaging, sensing, and photonics. In this study, we reported a one-step synthesis of photoluminescent CDs from Laurus nobilis leaves particularly spread in the Mediterranean area. The resulting nanoparticles (NPs) exhibited average diameters of 3–5 nm and high colloidal stability in water. Structural analysis by X-Rays Diffraction revealed the presence of amorphous graphitic domains, while infrared spectroscopy confirmed oxygenated functional groups on the CD surface. Spectrofluorimetric analysis showed excitation-dependent blue–green emission with a maximum at 490 nm that can be applied also as label agents for cells. The environmental sustainability of the synthetic procedure was evaluated through a Life Cycle Assessment (LCA), highlighting that the current impacts were primarily associated with electricity consumption, due to the laboratory-scale nature of the process. These impacts are expected to decrease significantly with future scale-up and process optimization.

Applied Nano doi: 10.3390/applnano6030018

Authors: Gabriel Tchuente Kamsu Eugene Jamot Ndebia

Esophageal squamous cell carcinoma (ESCC) accounts for the majority of esophageal cancers worldwide, with a poor prognosis and increasing resistance to conventional treatments. Faced with these limitations, nanoparticles (NPs) are attracting growing interest as innovative therapeutic agents capable of improving specificity and efficacy and reducing systemic toxicity. This study critically examines the pharmacological effects, mechanisms of action, and toxicity profiles of different metallic or organic nanoparticles tested on ESCC cell lines. Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) 2020 guidelines were followed by a meticulous literature search of Google Scholar, Web of Science, PubMed/Medline, and Scopus databases to achieve this goal. The results show that the anti-tumor properties vary according to the type of nanoparticle (copper(II) oxide (CuO), silver (Ag), gold (Au), nickel(II) oxide (NiO), nano-curcumin, etc.), the synthesis method (chemical vs. green), and the biological activity assessment method (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), Bromodeoxyuridine (BrdU), Cell Counting Kit-8 (CCK8) assays, etc.). NPs derived from green synthesis, such as those based on Moringa oleifera, Photinia glabra, or pomegranate bark, exhibit moderate cytotoxic activity (50% inhibitory concentration (IC50) between 92 and 500 µg/mL) but show good tolerance on normal cells. In contrast, chemically synthesized NPs, such as Cu(II) complexes with 1,3,5-benzenetricarboxylic acid (H3btc) or 1,2,4-triazole (Htrz), show lower IC50 (34–86 µM), indicating more marked cytotoxicity towards cancer cells, although data on their toxicity are sometimes lacking. In addition, multifunctional nanoparticles, such as gold-based nano-conjugates targeting Cluster of Differentiation 271 (CD271) or systems combined with doxorubicin, show remarkable activity with IC50 below 3 µM and enhanced tumor selectivity, positioning them among the most promising candidates for future clinical application against ESCC. The most frequently observed mechanisms of action include induction of apoptosis (↑caspases, ↑p53, ↓Bcl-2), oxidative stress, and inhibition of proliferation. In conclusion, this work identifies several promising nanoparticles (silver nanoparticles derived from Photinia glabra (PG), gold-based nano-immunoconjugates targeting CD271, and silver–doxorubicin complexes) for future pharmaceutical exploitation against ESCC. However, major limitations remain, such as the lack of methodological standardization, insufficient in vivo and clinical studies, and poor industrial transposability. Future prospects include the development of multifunctional nanocomposites, the integration of biomarkers for personalized targeting, and long-term toxicological assessment.

Applied Nano doi: 10.3390/applnano6030017

Authors: Danil V. Shershnev Natalia A. Virts Igor A. Gladskikh Pavel V. Geydt Mikhail A. Panfilov Alexey Yu. Vorob’ev Alexander E. Moskalensky

Localized therapeutic action and targeted drug release offer compelling advantages over traditional systemic drug administration. This is particularly important for nitric oxide (NO), whose biological effects vary greatly depending on concentration and cellular environment. Light-sensitive NO donors are promising for achieving precise, on-demand NO release. However, their efficiency and photostability are limited by competing photophysical processes and the generation of reactive oxygen species (ROS). In this study, we investigate hybrid systems composed of photosensitive nitric oxide (NO) donors and silver island films (SIFs). The influence of localized surface plasmon on non-radiative relaxation pathways and ROS generation is the main focus of the paper. Upon excitation at 500 nm, we observed several-fold increase in NO release, attributed to resonant interactions between the plasmonic field and the dye molecules. By tuning the thickness of a SiO2 buffer layer, we identified key parameters affecting process efficiency: the spectral overlap between the plasmon resonance and the sensitizer’s absorption band, and the distance between the nanoparticle and the molecule. Additionally, singlet oxygen generation increase was observed. These findings demonstrate the potential of plasmonic enhancement to controllably boost photochemical activity in organic systems, paving the way for advanced applications in phototherapy and biomedical diagnostics.

Applied Nano doi: 10.3390/applnano6030016

Authors: Sindy Bello Robinson Aguirre Ocampo Julián Arias Velandia Alejandro Zuleta Gil Esteban Correa Wilber Silva Julián Andrés Lenis Rodas Carlos Arrieta Francisco Bolívar Cesar Nieto Félix Echeverria

Hydrogen is emerging as a key energy vector for the transition toward renewable and sustainable energy sources. However, its safe and efficient storage remains a significant technical challenge in terms of cost, safety, and performance. In this study, we aimed to address the kinetic limitations of Mg by synthesizing catalyzed Mg@Ni systems using commercially available micrometric magnesium particles (~26 µm), which were decorated via electroless nickel plating under both aqueous and anhydrous conditions. Morphological and compositional characterization was carried out using SEM, EDS, and XRD. The resulting materials were evaluated through Temperature-Programmed Desorption (TPD), DSC, and isothermal hydrogen absorption/desorption kinetics. Reversibility over multiple absorption–desorption cycles was also investigated. The synthesized Mg@NiB system shows a reduction of 37 °C in the hydrogen release activation temperature at atmospheric pressure and a decrease of 167.3 °C under high vacuum conditions (4.5 × 10−7 MPa), in addition to a reversible hydrogen absorption/desorption capacity of 3.5 ± 0.09 wt.%. Additionally, the apparent activation energy for hydrogen desorption was lower (161.7 ± 21.7 kJ/mol) than that of hydrogenated commercial pure magnesium and was comparable to that of milling MgH2 systems. This research is expected to contribute to the development of efficient and low-cost processing routes for large-scale Mg catalysis.

Applied Nano doi: 10.3390/applnano6030015

Authors: Swapnil S. Bamane Ozgur Keles

Polymer matrix composites (PMCs) are crucial for their applications in aerospace, electronics, defense, and structural materials. PMCs reinforced with nanofillers offer substantial potential for enhanced thermal and mechanical performance. Although there have been significant developments in nanofiller-based high-performance composites involving graphene, carbon nanotubes, and metal oxides, the smallest of all the fillers, the graphene quantum dot (GQD), has not been explored thoroughly. The objective of this study is to investigate the effects of GQDs on the thermal properties of epoxy nanocomposites using all-atom molecular dynamics (MD) simulations. Specifically, the influence of GQDs on the glass transition temperature (Tg) and coefficient of linear thermal expansion (CTE) of the bisphenol F epoxy is evaluated. Further, the effects of surface functionalization and edge functionalization of GQDs are analyzed. Results demonstrate that the inclusion of functionalized GQDs leads to a 16% improvement in Tg, attributed to enhanced interfacial interactions and restricted molecular mobility in the epoxy network. MD simulations reveal that functional groups on GQDs form strong physical and chemical interactions with the polymer matrix, effectively altering its dynamics at the Tg. These results provide key molecular-level insights into the design of the next generation of thermally stable epoxy nanocomposites for high-performance applications in aerospace and defense.

Applied Nano doi: 10.3390/applnano6030014

Authors: Şuheda Bolat Zafer Sancak Abdurrahman Gümüş Idris Yazgan

Amino acids are not just monomers of proteins, but they can also carry biological functions. L-cysteine (Cys), L-proline (Pro), L-asparagine (Asn), and L-glutamic acid (Glu) were used to evaluate how different amino acid chemistries alter the morphology and size of the silver nanoparticles (AgNPs) synthesized in the presence of two carbohydrate ligands, which were lactose methoxyaniline (LMA) and galactose 5-aminosalicylic acid (G5AS). UV–vis, infrared (IR), High-Resolution Transmission Electron Microscopy (HR-TEM) and X-ray diffraction (XRD) characterizations revealed that the effect of amino acids on the characteristics of the AgNPs showed dependence on the carbohydrate ligand chemistry. In the case of LMA, AgNPs shifted from aggregates to anisotropic nanoparticles, larger aggregates, and a mixture of anisotropic and 1D nanoparticles in the presence of Cys, Glu, Asn and Pro amino acids, respectively. In contrast to this, the introduction of Cys and Asn caused the formation of cluster-like AgNPs and larger rounded nanoparticles, while G5AS-synthesized AgNPs were multigonal 0D particles. Moreover, Glu and Pro contributed the resistance of silver oxide formation on the particles. Antibacterial characterization showed that LMA_Glu_AgNPs were the most effective ones, while LMA_Cys_AgNPs and G5AS_Cys_AgNPs, which were the smallest AgNPs, did not show any significant antibacterial activity.

Applied Nano doi: 10.3390/applnano6030013

Authors: Aiden Jurcenko Olesia Gololobova Kenneth W. Witwer

Super-resolution microscopy (SRM) has revolutionized our understanding of subcellular structures, including cell organelles and viruses. For human immunodeficiency virus (HIV), SRM has significantly advanced knowledge of viral structural biology and assembly dynamics. This review analyzes how SRM techniques (particularly PALM, STORM, STED, and SIM) have been applied over the past decade to study HIV structural components and assembly. By categorizing and comparing studies based on SRM methods, HIV components, and labeling strategies, we assess the strengths and limitations of each approach. Our analysis shows that PALM is most commonly used for live-cell imaging of HIV Gag, while STED is primarily used to study the viral envelope (Env). STORM and SIM have been applied to visualize various components, including Env, capsid, and matrix. Antibody labeling is prevalent in PALM and STORM studies, targeting Env and capsid, whereas fluorescent protein labeling is mainly associated with PALM and focused on Gag. A recent emphasis on Gag and Env points to deeper investigation into HIV assembly and viral membrane dynamics. Insights from SRM studies of HIV not only enhance virological understanding but also inform future research in therapeutic strategies and delivery systems, including extracellular vesicles.

Applied Nano doi: 10.3390/applnano6030012

Authors: Nachiket S. Makh Ajit D. Kelkar

Carbon nanotubes (CNTs) are cylindrical nanostructures formed by rolling a graphene sheet—a hexagonal lattice of carbon atoms—into a tube. Based on the rolling direction, CNTs are categorized as armchair, zigzag, or chiral. The chiral vector, derived from the graphene lattice, defines the CNT’s structure, with chiral CNTs denoted by indices (n, m), where m > 0 and m ≠ n. The mechanical properties and structural stability of CNTs are highly sensitive to defects and impurities within their atomic framework. Among these, point defects such as single-atom vacancies are the most prevalent and can significantly degrade mechanical performance. These defects alter stress distribution, reduce stiffness, and impair strength, thereby limiting the functional reliability of CNTs in advanced applications such as nanocomposites, sensors, and electronic devices. This study examines the influence of vacancy defects on CNT mechanical behavior through a multiscale modeling framework. Molecular dynamics (MD) simulations are conducted using LAMMPS, with structural visualization via Visual Molecular Dynamics (VMD). Concurrently, a finite element (FE) model is developed in ANSYS, where the CNT is idealized as a space frame of elastic beam elements representing carbon–carbon bonds. The integration of atomistic and continuum approaches offers a comprehensive understanding of defect-induced mechanical degradation. The MD and FEM results are in strong agreement with findings in existing literature, validating the adopted methodology. These findings contribute valuable insights into the design and optimization of CNT-based materials for high-performance engineering applications.

Applied Nano doi: 10.3390/applnano6030011

Authors: Mohamed Hefny Rasha Gh. Orabi Medhat M. Kamel Haitham Kalil Mekki Bayachou Nasser Y. Mostafa

This study investigates the development and sensing profile of synthetic melanin nanoparticle-coated electrodes for the electrochemical detection of heavy metals, including lead (Pb), cadmium (Cd), cobalt (Co), zinc (Zn), nickel (Ni), and iron (Fe). Synthetic melanin films were prepared in situ by the deacetylation of diacetoxy indole (DAI) to dihydroxy indole (DHI), followed by the deposition of DHI monomers onto indium tin oxide (ITO) and glassy carbon electrodes (GCE) using cyclic voltammetry (CV), forming a thin layer of synthetic melanin film. The deposition process was characterized by electrochemical quartz crystal microbalance (EQCM) in combination with linear sweep voltammetry (LSV) and amperometry to determine the mass and thickness of the deposited film. Surface morphology and elemental composition were examined using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). In contrast, Fourier-transform infrared (FTIR) and UV–Vis spectroscopy confirmed the melanin’s chemical structure and its polyphenolic functional groups. Differential pulse voltammetry (DPV) and amperometry were employed to evaluate the melanin films’ electrochemical activity and sensitivity for detecting heavy metal ions. Reproducibility and repeatability were rigorously assessed, showing consistent electrochemical performance across multiple electrodes and trials. A comparative analysis of ITO, GCE, and graphite electrodes was conducted to identify the most suitable substrate for melanin film preparation, focusing on stability, electrochemical response, and metal ion sensing efficiency. Finally, the applicability of melanin-coated electrodes was tested on in-house heavy metal water samples, exploring their potential for practical environmental monitoring of toxic heavy metals. The findings highlight synthetic melanin-coated electrodes as a promising platform for sensitive and reliable detection of iron with a sensitivity of 106 nA/ppm and a limit of quantification as low as 1 ppm.

Applied Nano doi: 10.3390/applnano6020010

Authors: Fabricio N. Molinari Emanuel Bilbao Leandro N. Monsalve

Placing printed conductive patterns onto nonplanar substrates is a challenging task. In this work, we tested a simple method for depositing inkjet-printed conductive patterns onto 3D-printed pieces with cavities and sharp edges. First, a silver nanoparticle ink was used to print conductive patterns onto a flexible and porous substrate made of electrospun polycaprolactone (PCL). Then, the printed patterns were transferred to 3D-printed pieces made of polylactic acid (PLA) by temperature-promoted adhesion. Finally, the printed patterns were cured to render them conductive. The influence of the number of printed layers on their electrical and mechanical properties was evaluated. The printed patterns were also transferred to flexible substrates, such as thermoplastic polyurethane (TPU) and polyethylene terephthalate (PET) sheets, achieving conductivity after curing. Moreover, the printed patterns were effective for modular interconnection among successive transferred patterns, since it was possible to achieve electrical contact between them during the transfer process.

Applied Nano doi: 10.3390/applnano6020009

Authors: Eknath D. Ahire Namrata Savaliya Kalarav V. Makwana Sagar Salave Mandeep Kaur Banth Bhavesh Bhavsar Dignesh Khunt Bhupendra G. Prajapati

Protein-bound nano-injectable solutions represent a cutting-edge advancement in nanomedicine, offering a versatile platform for precise and controlled drug delivery. By leveraging the biocompatibility and functional versatility of proteins such as albumin, gelatin, and casein, these nano systems enhance drug solubility, prolong circulation time, and improve site-specific targeting, which are particularly beneficial in cancer and inflammatory diseases. This review provides a comprehensive overview of their formulation strategies, physicochemical characteristics, and biological behavior. Emphasis is placed on therapeutic applications, regulatory considerations, fabrication techniques, and the underlying mechanisms of drug–protein interactions. This review also highlights improved pharmacokinetics and reduced systemic toxicity, while also critically addressing challenges like immunogenicity, protein instability, and production scalability. Recent FDA-approved formulations and emerging innovations in precision medicine and theranostics underscore the transformative potential of protein-based nanosuspensions in next-generation drug delivery systems.

Applied Nano doi: 10.3390/applnano6020008

Authors: Md Nuruzzaman Yanju Liu Mohammad Mahmudur Rahman Saifullah Omar Nasif Ravi Naidu

The synthesis of calcium carbonate (CaCO3) nanoparticles has gained an increasing interest due to their improved properties and diverse industrial applications. Among various synthesis techniques, the mechanochemical synthesis process has emerged as a promising route for nano-CaCO3 synthesis. A high-energy ball mill is required for synthesizing nano-CaCO3, whereas post-milling heat treatment facilitates completing the reaction that remains incomplete during milling. Post-milling heat treatment may also influence the properties of synthesized CaCO3, which has not yet been thoroughly investigated. This study investigated the influence of post-milling heat treatment on the polymorphs, micromorphology, and particle size distribution of CaCO3. The results indicated that the heat treatment of the as-milled powder enhanced the homogeneity of crystal polymorphs while maintaining the particle sizes within the nano-range (<100 nm). X-ray diffraction (XRD) analysis identified two polymorphs (vaterite and calcite) in samples obtained from different milling intensities. However, after heat treatment, all vaterite transformed into calcite. A bimodal particle size distribution was observed in CaCO3 nanoparticles and was influenced by both the milling and heating intensities. It was observed that 60 min heat applied to 30 min as-milled powder was enough to produce nano-CaCO3 (<50 nm) where the percentage of larger particles (<250 nm) became negligible (~1%). Micromorphology images confirmed the transformation of crystal polymorphs and the reduction in particle size.

Applied Nano doi: 10.3390/applnano6020007

Authors: Giovanny Perez-Parra Nayely Torres-Gomez Vineetha Vinayakumar Diana F. Garcia-Gutierrez Selene Sepulveda-Guzman Domingo I. Garcia-Gutierrez

Nanostructured hybrid materials based on the combination of semiconductor QDs and GO are promising candidates for different optoelectronic and catalytic applications and being able to produce such hybrid materials in solution will expand their possible range of applications. In the current work, capping ligand-exchange procedures have been developed to replace the lead oleate normally found on the surface of PbS QDs synthesized by the popular hot-injection method. After the capping ligand-exchange process, the QDs are water soluble, which makes them soluble in most GO solutions. Solution-processed nanostructured hybrid materials based on GO flakes decorated with ligand-exchanged (EDT, TBAI and L-Cysteine) PbS QDs were synthesized by combining PbS QDs and GO solutions. Afterward, the resulting hybrid materials were thoroughly characterized by means of FTIR, XPS, Raman, UV-Vis-NIR and photoluminescence spectroscopy, as well as SEM and TEM techniques. The results indicate a clear surface chemistry variation in the capping ligand-exchanged PbS QDs, showing the presence of the exchanged ligand molecules. Thin films from the solution-processed nanostructured hybrid materials were deposited by the spin coating technique, and their optoelectronic properties were studied. Depending on the capping ligand molecule, the photoresponse and resistance of the thin films varied; the sample with the EDT ligand exchange showed the highest photoresponse and the lowest resistance. This surface chemistry had a direct effect on the charge carrier transfer and transport behavior of the nanostructured hybrid materials synthesized. These results show a novel and accessible route for synthesizing solution-processed and affordable nanostructured hybrid materials based on semiconductor QDs and GO. Additionally, the importance of the surface chemistry displayed by the PbS QDs and GO was clearly seen in determining the final optoelectronic properties displayed by their hybrid materials.

Applied Nano doi: 10.3390/applnano6020006

Authors: Md. Iftekhar Shams Md. Yamin Kabir Md. Yasin Ali Masum Billah Most. Jakiya Sultana Bristi Hironori Kaminaka Dagmawi Abebe Zewude Shinsuke Ifuku

Rice is a staple food for nearly half the world population. Rice cultivation relies heavily on urea fertilization. However, the use of urea is prone to significant losses and contributes to environmental pollution. This study was aimed at fabricating nitrogen-rich chitin nanomaterials and assessing their effects on the growth and yield of rice. Chitin nanofibers (ChNF), with widths ranging from 10 to 30 nm, were successfully isolated from shrimp shells by chemical pretreatment and mechanical fibrillation. Pot-grown rice plants were treated with various concentrations of ChNF and urea in a completely randomized design with five replicates. ChNF treatment resulted in plant height (97.33 ± 1.53 cm), tiller number (17.67 ± 1.15 hill−1), straw yield (30.40 ± 1.93 g hill−1), and harvest indexes comparable to those achieved with urea treatment at harvest (97.33 ± 1.53 cm, 17.00 ± 1.73 hill−1, 26.47 ± 2.39 g hill−1 and 44.12%, respectively). The grain yield using urea (22.70 g hill−1) was almost identical to that achieved with 0.01% ChNF (22.22 g hill−1), which may be attributable to the increased nitrate-nitrogen (N) and ammonium-N availability, reduced nitrogen loss, and enhanced microbial activity associated with 0.01% ChNF. The study findings indicate that shrimp-derived ChNF is a promising functional nanomaterial for rice cultivation, with potential as a partial or full replacement for urea in sustainable rice production.

Applied Nano doi: 10.3390/applnano6010005

Authors: Nkanyiso C. Nkosi Albertus K. Basson Zuzingcebo G. Ntombela Nkosinathi G. Dlamini Rajasekhar V. S. R. Pullabhotla

Nanotechnology offers effective solutions for removing contaminants and harmful bacteria from polluted water. This study synthesized copper nanoparticles using a carbohydrate-based bioflocculant derived from Proteus mirabilis AB 932526.1. The bioflocculant is a natural polymer that facilitates the aggregation of particles, enhancing the efficiency of the nanoparticle synthesis process. Characterization of the bioflocculant and copper nanoparticles was conducted using Fourier Transform Infrared Spectroscopy, Scanning Electron Microscopy, Energy-Dispersive X-ray Spectroscopy, Ultraviolet-Visible Spectroscopy, X-ray Diffraction, and Transmission Electron Microscopy techniques to assess their properties, flocculation efficiency, and antibacterial characteristics. The optimal flocculation efficiency of 80% was achieved at a copper nanoparticle concentration of 0.4 mg/mL, while a concentration of 1 mg/mL resulted in a lower efficiency of 60%. The effects of biosynthesized copper nanoparticles on human-derived embryonic renal cell cultures were also investigated, demonstrating that they are safe at lower concentrations. The copper nanoparticles effectively removed staining dyes such as safranin (90%), carbol fuchsine (88%), methylene blue (91%), methyl orange (93%), and Congo red (94%), compared to a blank showing only 39% removal. Furthermore, when compared to both chemical flocculants and bioflocculants, the biosynthesized copper nanoparticles exhibited significant nutrient removal efficiencies for nitrogen, sulfur, phosphate, and total nitrates in coal mine and Vulindlela domestic wastewater. Notably, these biosynthesized copper nanoparticles demonstrated exceptional antibacterial activity against both Gram-positive and Gram-negative bacteria.

Applied Nano doi: 10.3390/applnano6010004

Authors: Ana Carolina Carvalho Lopes Serrano Mateus Costa Viana Natalha Vicentina Pinto Eduardo Burgarelli Lages Guilherme Carneiro Gabriel Silva Marques Borges

Self-emulsifying drug delivery systems (SEDDS) consist of isotropic mixtures of oils, surfactants, and solvents that after dispersion emulsify in the aqueous media of the gastrointestinal tract (GIT). SEDDS can deliver hydrophobic drugs, which could enhance their oral bioavailability by protecting them from precipitation and degradation. However, it is important to find the appropriate ratio of their excipients to produce emulsions with the desirable physicochemical characteristics. In this sense, Design of Experiments (DoE) approaches such as central composite design (CCD) and Box–Behnken design (BBD) can reduce the number of experiments necessary to determine the best composition and preparation process of a SEDDS formulation. Therefore, this article aims to discuss drug delivery through SEDDS and how DoE approaches can aid researchers in achieving product quality specifications and optimizing the formulation preparation processes. For this, the most recent and relevant papers were analyzed. This review is expected to guide future research directions for more rational development of SEDDS.

Applied Nano doi: 10.3390/applnano6010003

Authors: José Queiroz Arthur Figueredo Bruno Silva Sá Daniel Carneiro Moreira João Bueno Nunes Peter Eaton José Roberto Souza de Almeida Leite Andreanne Gomes Vasconcelos

Baru nut oil (Dipteryx alata Vogel) is a lipidic extract from a species endemic to the Cerrado biome, renowned for its antioxidant potential. This study aimed to develop a nanoemulsion containing baru nut oil (BNON) using lecithin and polysorbate 80, and to evaluate its antioxidant activity and cytotoxicity. The physicochemical properties of BNON were characterized, and its cytotoxicity was assessed in human erythrocytes and keratinocytes. Antioxidant activity was evaluated using the DPPH method and inhibition of AAPH-induced hemolysis. BNON exhibited a droplet size of 530.1 ± 20.48 nm, a polydispersity index of 0.496 ± 0.057, and a zeta potential of −35.7 ± 2.19 mV. Free baru nut oil showed no cytotoxicity to keratinocytes or erythrocytes within the concentration ranges tested (1.0–0.031 mg/mL and 0.8–0.006 mg/mL, respectively). In contrast, BNON displayed cytotoxic effects on keratinocytes and erythrocytes only at the highest tested concentration. Atomic force microscopy analysis of erythrocytes from the hemolysis assay revealed normal morphology for cells treated with free oil at 0.8 mg/mL, whereas cells treated with BNON at the same concentration exhibited a slightly widened concave center. Free oil at 0.8 mg/mL significantly protected erythrocytes from AAPH-induced hemolysis, while BNON did not. However, BNON (5 mg/mL) demonstrated free radical scavenging activity, quantified at 0.0074 mg Trolox equivalents/mg via the DPPH assay. These findings suggest that baru nut oil has potential as an antioxidant product, although further optimization of the nanoformulation is required.

Applied Nano doi: 10.3390/applnano6010002

Authors: Johann Michael Köhler

DNA encoding the 16S rRNA of bacteria is a type of nanometer-sized information storage that can be used to characterize bacterial communities in soils. Reading this molecular ’nano-archive’ is not only of interest for characterizing recent local ecological conditions but can also provide valuable information about human impacts on soils in the past. This is of great interest for archaeology and for understanding the ecological consequences of past human activities on recent ecological conditions. Powerful sequencing methods such as the Illumina process allow many different DNA sequences to be determined in parallel and provide very efficient data sets that reflect the composition of soil bacterial communities in topsoil layers as well as in translocated and covered soils of archaeological sites such as settlements, burials or workplaces. Here, a brief overview of recent developments in the use of these molecular nano-archives for the study of archaeological soil samples is given using typical examples.

Applied Nano doi: 10.3390/applnano6010001

Authors: Carlos R. Michel

Pollution of freshwater by synthetic organic dyes is a major concern due to their high toxicity and mutagenicity. In this study, the degradation of Congo red (CR) and malachite green (MG) dyes was investigated using nanostructured Gd2O3. It was prepared using the coprecipitation method, using gadolinium nitrate and concentrated formic acid, with subsequent calcination at 600 °C. Its morphology corresponds to hollow porous microspheres with a size between 0.5 and 7.5 μm. The optical bandgap energy was determined by using the Tauc method, giving 4.8 eV. The degradation of the dyes was evaluated by UV-vis spectroscopy, which revealed that dissociative adsorption (in the dark) played a key role. It is explained by the cleavage and fragmentation of the organic molecules by hydroxyl radicals (•OH), superoxide radicals (•O2−) and other reactive oxygen species (ROS) produced on the surface of Gd2O3. For CR, the degradation percentage was ~56%, through dissociative adsorption, while UV light photocatalysis increased it to ~65%. For MG, these values were ~78% and ~91%, respectively. The difference in degradation percentages is explained in terms of the isoelectric point of solid (IEPS) of Gd2O3 and the electrical charge of the dyes. FTIR and XPS spectra provided evidence of the role of ROS in dye degradation.

Applied Nano doi: 10.3390/applnano5040019

Authors: Jack E. Bezdek Keith A. Strevett Tohren C. G. Kibbey

Interest in the use of nanoparticles in agriculture has grown in recent years due to their potential abilities across a range of applications that could increase agricultural production, improve the efficiency of nutrient delivery, or improve pest management. However, as with any application of nanomaterials, concern exists about potential risks to human health. Because many applications might result in the attachment of nanoparticles to produce surfaces, it is important to understand the conditions under which rinsing is likely to remove nanoparticles from surfaces and the degree to which they can be removed. This work explored the rinsing removal of two types of nanoparticles, titanium dioxide (TiO2) and zinc oxide (ZnO), from spinach leaf surfaces in the absence and presence of biofilms based on extracellular polymeric substances (EPS). A hypothesis driving the work was that the presence of biofilms might enhance the retention of nanoparticles. The work combined experiments to determine surface energy parameters for fresh and rotten spinach, for use in extended DLVO (xDLVO) calculations, as well as direct rinsing experiments to explore nanoparticle removal from spinach surfaces. Nanoparticles were quantified using backscattered scanning electron microscopy using techniques developed for the work. Results of xDLVO calculations suggest that the presence of biofilms may actually be likely to reduce the retention of nanoparticles by produce surfaces, although this effect was not apparent in rinsing experiments, which exhibited similar removal of high-concentration TiO2 from spinach leaves. Overall, nanoparticles deposited from high-concentration suspensions were found to be removed to a greater degree by rinsing, while those deposited from low-concentration suspensions exhibited no apparent release, even under conditions where release might be favored.

Applied Nano doi: 10.3390/applnano5040018

Authors: Norbert Konradt Laura Schneider Stefan Bianga Detlef Schroden Peter Janknecht Georg Krekel

While microparticles can be removed by a filtration step at a drinking water treatment plant (DWTP), engineered nanoparticles (ENPs), which are widely used in industry, commerce and households, pose a major problem due to their special properties, e.g., size, reactivity and polarity. In addition, many ENPs exhibit toxic potential, which makes their presence in drinking water undesirable. Therefore, this study investigated the removal of ENPs in the laboratory and at a pilot-scale DWTP. Eight ENPs were synthesized and tested for stability in different types of water. Only three of them were stable in natural water: cetyltrimethylammonium bromide-coated gold (CTAB/AuNPs), polyvinylpyrrolidone-stabilized gold and silver nanoparticles (PVP/AuNPs, PVP/AgNPs). Their retention on quartz sand, silica gel and fresh anthracite was low, but CTAB/AuNPs could be retained on fresh river sand and thus should not overcome riverbank filtration, while PVP/AuNPs and PVP/AgNPs showed no retention and may be present in raw water. During ozonation, PVP/AuNPs remained stable while PVP/AgNPs were partially degraded. The advanced oxidation process (AOP) was less effective than ozone. PVP/AgNPs were almost completely retained on the pilot plant anthracite sand filter coated with manganese(IV) oxide and ferrihydrite from raw water treatment. PVP/AuNPs passed the filter with no retention. In contrast to PVP/AuNPs, PVP/AgNPs and CTAB/AuNPs were also retained on activated carbon. The integration of a flocculation step with iron(III) salts can improve ENP removal, with PVP/AuNPs requiring higher flocculant doses than PVP/AgNPs. PVP/AuNPs, in particular, are well-suited for testing the effectiveness of water treatment. Further data on the occurrence of stable ENPs in raw water and their behavior during water treatment are needed to perform a risk assessment and derive the measures.

Applied Nano doi: 10.3390/applnano5040017

Authors: Md Ibrahim Khalil Tanim Anahita Emami

Flexible nanocomposite sensors hold significant promise in various applications, such as wearable electronics and medical devices. This research aims to tailor the flexibility and sensitivity of 3D-printed piezoresistive nanocomposite pressure sensors through geometric design, by exploring various simple cellular structures. The geometric designs were specifically selected to be 3D printable with a flexible material, allowing evaluation of the impact of different structures on sensor performance. In this study, we used both experimental and finite element (FE) methods to investigate the effect of geometric design on piezoresistive sensors. We fabricated the sensors using a flexible resin mixed with conductive nanoparticles via a Stereolithography (SLA) additive manufacturing technique. Electromechanical testing was carried out to evaluate the performance of four different sensor designs. Finite element (FE) models were developed, and their results were compared with experimental data to validate the simulations. The results demonstrated that auxetic structure exhibited the highest sensitivity and lowest stiffness both in experimental and FE analysis, highlighting its potential for applications requiring highly responsive materials. The validated FE model was further used for a parametric study of one of the promising simple designs, revealing that variations in geometric parameters significantly impact piezoresistive sensitivity. These findings provide valuable insights for advancing the development of pressure sensors with tailored sensitivity characteristics.

Applied Nano doi: 10.3390/applnano5040016

Authors: Islam Gomaa Haitham Kalil Ahmed I. Abdel-Salam Medhat A. Ibrahim Mekki Bayachou

Eco-friendly iron and manganese oxide nanoparticles (Fe2O3 and Mn2O3) were synthesized and integrated into graphene sheets to form uniform composites. These composites were then embedded in polyvinyl alcohol (PVA) fibers using electrospinning. Comprehensive characterization of the composites and the final composite fibers was conducted using XRD, FE-SEM, and FTIR to analyze their structural complexity and morphological differences. The antibacterial efficacy of the resulting PVA nanofibers was evaluated against Escherichia coli, which is a common pathogen in hospital environments. The results show a significant bactericidal effect against these bacteria, which highlights their potential in medical applications, such as functional bandages and wound dressings. This study paves the way for potential commercial applications of these nanofibers in healthcare settings.

Applied Nano doi: 10.3390/applnano5040015

Authors: Jayshree H. Ahire Qi Wang Yuewei Tao Yimin Chao Yongping Bao

Silver nanoparticles (AgNPs) demonstrate potential in treating aggressive cancers such as triple-negative breast cancer (TNBC) in preclinical models. To further the development of AgNP-based therapeutics for clinical use, it is essential to clearly define the specific physicochemical characteristics of the nanoparticles and connect these properties to biological outcomes. This study addresses this knowledge gap through detailed investigations into the structural and surface functional relationships, exploring the mechanisms, safety, and efficacy of AgNPs in targeting TNBC. The surface functionality of nanoparticles is crucial not only for their internalization into cancer cells but also for enhancing their toxicity toward tumor cells. Although the nanoparticles internalized into cancer cells, they failed to exhibit their full toxicity against the cancer. Herein we report a solvent-assisted synthesis amine, mercaptohexanol and bifunctional silver nanoparticles and performing comparative study to understand their selectivity and toxicity toward TNBC cells. The nanoparticles are fully characterized by UV–visible absorption spectroscopy, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and dynamic light scattering measurement (DLS). The synthesis method achieves an extremely high yield and surface coating ratio of synthesized colloidal AgNPs. Our findings reveal that the amine-capped AgNPs exhibit significant selective toxicity against TNBC cell lines MCF7 and MDA-MB-231 at a concentration of 40 µg/mL without affecting normal breast cell lines MCF10A. This study underscores the potential of functionalized AgNPs in developing safe and targeted therapeutic approaches for treating aggressive cancers like TNBC, laying the groundwork for future clinical advancements.

Applied Nano doi: 10.3390/applnano5040014

Authors: Anaís Bezerra de Gusmão Priscilla Barbosa Sales de Albuquerque Ana Carolina de Carvalho Correia

Wound healing is rarely seen as a problem in healthy individuals; however, under certain pathophysiological conditions, this process can be impaired, leading to the emergence of chronic wounds, which are themselves a serious public health problem. This work aimed to review the most important recent literature on the use of nanoparticles of Ag, Au, and Zn produced from plant extracts and their application as healing agents. To that end, we provide an insight into the pathophysiology of wound healing and the main routes to obtaining metallic nanoparticles. The methodology of synthesis, which is part of the so-called green synthesis, has been the focus of several studies on the use of medicinal plants as a substrate to produce silver, gold, and zinc nanoparticles. Their use as wound healing agents is closely related to their natural antimicrobial, anti-inflammatory, and cicatrizing properties. Finally, we address in vitro and in vivo studies on the efficiency of metallic nanoparticles (MNPs) synthesized from plant extracts and applied to wound healing in different pharmaceutical forms. For instance, the excellent wound contraction rates obtained from silver and gold NPs, respectively, were obtained from Euphorbia milii (92%) and Plectranthus aliciae (almost 97%) extracts in in vivo and in vitro analyses. Based on the satisfactory results, we find that MNPs are a potential therapeutic alternative compared to traditional synthetic healing agents and foresee the production of new pharmaceutical drugs.

Applied Nano doi: 10.3390/applnano5030013

Authors: Laury Kanku Kassim Olasunkanmi Badmus Fracois Wewers

Recent improvements in advanced technology for toxic chemical remediation have involved the application of titanium oxide nanoparticles as a photocatalyst. However, the large energy bandgap associated with titanium oxide nanoparticles (3.0–3.20 eV) is a limitation for their application as a photocatalyst within the solar spectrum. Various structural modification methods have led to significant reductions in the energy bandgap but not without their disadvantages, such as electron recombination. In the current investigation, biochar was made from the leaves of an invasive plant (Acacia saligna) and subsequently applied as a support in the synthesis of titanium oxide nanoparticles. The characterization of biochar-supported titanium oxide nanoparticles was performed using scanning electron microscopy, Fourier transformer infrared, X-ray diffraction, and Brunauer–Emmett–Teller analyses. The results showed that the titanium oxide was successfully immobilized on the biochar’s external surface. The synthesized biochar-supported titanium oxide nanoparticles exhibited the phenomenon of small hysteresis, which represents the typical type IV isotherm attributed to mesoporous materials with low porosity. Meanwhile, X-ray diffraction analysis revealed the presence of a mixture of rutile and anatase crystalline phase titanium oxide. The synthesis of biochar-supported titanium oxide nanoparticles was highly efficient in the degradation of Orange II Sodium dye under solar irradiation. Moreover, 83.5% degradation was achieved when the biochar-supported titanium oxide nanoparticles were used as photocatalysts in comparison with the reference titanium oxide, which only achieved 20% degradation.

Applied Nano doi: 10.3390/applnano5030012

Authors: Moeng Geluk Motitswe Kassim Olasunkanmi Badmus Lindiwe Khotseng

Toxic metal wastewater is a challenge for exposed terrestrial and aquatic environments, as well as the recyclability of the water, prompting inputs for the development of promising treatment methods. Consequently, the rGO/ZnONP nanocomposite was synthesized at room temperature for four hours and was tested for the adsorption of cadmium and lead in wastewater. The optimized nanocomposite had the lowest band gap energy (2.69 eV), and functional group interactions were at 516, 1220, 1732, 3009, and 3460 cm−1. The nanocomposite showed good ZnO nanoparticle size distribution and separation on rGO surfaces. The nanocomposite’s D and G band intensities were almost the same, constituting the ZnO presence on rGO from the Raman spectrum. The adsorption equilibrium time for cadmium and lead was reached within 10 and 90 min with efficiencies of ~100%. Sips and Freundlich best fitted the cadmium and lead adsorption data (R2 ~ 1); therefore, the adsorption was a multilayer coverage for lead and a mixture of heterogenous and homogenous coverage for cadmium adsorption. Both adsorptions were best fitted by the pseudo-first-order model, suggesting the multilayer coverage dominance. The adsorbent was reused for three and seven times for cadmium and lead. The nanocomposite showed selectivity towards lead (95%) and cadmium (100%) in the interfering wastewater matrix. Conclusively, the nanocomposite may be embedded within upcoming lab-scale treatment plants, which could lead to further upscaling and it serving as an industrial wastewater treatment material.

Applied Nano doi: 10.3390/applnano5030011

Authors: Linh Dinh Lanesa Mahon Bingfang Yan

Nano-encapsulation and conjugation are the main strategies employed for drug delivery. Nanoparticles help improve encapsulation and targeting efficiency, thus optimizing therapeutic efficacy. Through nanoparticle technology, replacement of a defective gene or delivery of a new gene into a patient’s genome has become possible. Lipid nanoparticles (LNPs) loaded with genetic materials are designed to be delivered to specific target sites to enable gene therapy. The lipid shells protect the fragile genetic materials from degradation, then successfully release the payload inside of the cells, where it can integrate into the patient’s genome and subsequently express the protein of interest. This review focuses on the development of LNPs and nano-pharmaceutical techniques for improving the potency of gene therapies, reducing toxicities, targeting specific cells, and releasing genetic materials to achieve therapeutic effects. In addition, we discuss preparation techniques, encapsulation efficiency, and the effects of conjugation on the efficacy of LNPs in delivering nucleic acid materials.

Applied Nano doi: 10.3390/applnano5030010

Authors: Amartya Chakrabarti Emily Alessandri

ZnS is a II-VI semiconductor with a wide bandgap. ZnS-based nanomaterials have been produced in a variety of morphologies with unique properties and characteristic features. An extensive collection of research activities is available on various synthetic methodologies to produce such a wide variety of ZnS-based nanomaterials. In this comprehensive review, we thoroughly covered all the different synthetic techniques employed by researchers across the globe to produce zero-dimensional, one-dimensional, two-dimensional, and three-dimensional ZnS-based nanomaterials. Depending on their morphologies and properties, ZnS-based nanomaterials have found many applications, including optoelectronics, sensors, catalysts, batteries, solar cells, and biomedical fields. The properties and applications of ZnS-based nanostructures are described, and the scope of the future direction is highlighted.

Applied Nano doi: 10.3390/applnano5030009

Authors: Amit Bhardwaj Arun K. Singh

The leaves of the Murraya koenigii aromatic plant contain various specific phytochemicals, including lutein, β-carotene, vitamin C, nicotinic acids, and other polyphenols, which act as reducing agents to produce metallic nanoparticles from their respective precursors. In this study, we report the green synthesis of iron–cobalt bimetallic nanoparticles (Fe–Co BMNPs) using natural resources of reducing and capping agents from aqueous extract of Murraya koenigii leaves. The synthesized Fe–Co BMNPs were characterized using SEM, EDS, BET surface area, TGA, XRD, TEM, and VSM techniques, revealing their crystalline structure with a surface area of 83.22 m2 g−1 and particle sizes <50 nm. Furthermore, the photocatalytic ability of the synthesized Fe–Co BMNPs was examined concerning methylene blue dye (MBD) aqueous solution. The synthesized Fe–Co BMNPs exhibited promising potential for dye removal from aqueous solution in acidic and basic medium (>97% of 10 mg L−1).

Applied Nano doi: 10.3390/applnano5020008

Authors: Roy Strandberg Dustin Ray Debendra K. Das

This paper presents the continuation of experimental investigations conducted by the present authors to measure and compare the thermal and fluid dynamic performance of a residential hydronic air coil using nanofluids. The prior experiments were limited to testing only one volumetric concentration (1%) of aluminum oxide (Al2O3) nanofluid. They compared it with the base fluid, a 60% ethylene glycol/40% water mixture by mass (60% EG). The original tests revealed some deficiencies in the experimental setup, which was subsequently revised and improved. This paper summarizes the results of experiments from the improved test bed using three concentrations of Al2O3 nanofluids: 1, 2, and 3% volumetric concentrations prepared with an average particle size of 45 nm in a 60% EG dispersion. The test bed in these experiments simulates a small air handling system typical of heating, ventilation, and air conditioning (HVAC) applications in cold regions. Entering conditions for the air and liquid were selected to emulate typical commercial air handling systems operating in cold climates. Contrary to previous findings, our test results revealed that nanofluids did not perform as well as expected. Prior predictions from many analytical and numerical studies had promised significant performance gain. The performance of the 1% nanofluid was generally equal to that of the base fluid under identical inlet conditions. However, the performance of the 2% and 3% nanofluids was considerably lower than that of the base fluid. The higher concentration nanofluids exhibited heat rates up to 14.6% lower than the 60% EG and up to 44.3% lower heat transfer coefficient. The 1% Al2O3/60% EG exhibited a 100% higher pressure drop across the coil than the base fluid, considering equal heat output. This performance degradation was attributed to the inability to maintain nanofluid dispersion stability, agglomeration, and subsequent decline in the thermophysical properties.

Applied Nano doi: 10.3390/applnano5020007

Authors: Mattia Allieta Mauro Coduri Alberto Naldoni

Understanding the role of oxygen vacancies in the phase transformation of metal oxide nanomaterials is fundamental to design more efficient opto-electronic devices for a variety of applications, including sensing, spintronics, photocatalysis, and photo-electrochemistry. However, the structural mechanisms behind the phase transformation in reducible oxides remain poorly described. Here, we compare P25 and black TiO2 during the thermal anatase-to-rutile transformation using in situ synchrotron powder diffraction. The precise measurement of the phase fractions, unit cell parameters, and Ti-O bond sheds light on the phase transformation dynamics. Notably, we observe distinct temperature-dependent shifts in the relative phase fractions of anatase and rutile in both materials highlighting the role of the oxygen vacancy in promoting the phase transformation. We employ bond valence concepts for structural modeling, revealing unique trends in temperature evolution of Ti-O distances of black rutile, confirming that this TiO2 phase is preferentially reduced over anatase. These findings not only enhance our understanding of phase transitions in TiO2 but also open new ways for the design of advanced photocatalytic materials through targeted phase control.

Applied Nano doi: 10.3390/applnano5020006

Authors: Gerardo Miguel Bravo de Luciano Blanca Susana Soto-Cruz Anabel Romero-López Yesmin Panecatl-Bernal José Alberto Luna-López Miguel Ángel Domínguez-Jiménez

This work presents the green synthesis of iron oxide nanoparticles (IONPs) using Baccharis salicifolia extract and their incorporation in mesoporous silica MCM-41, obtaining an MCM-41@IONP composite. The MCM-41@IONP composite was characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), nitrogen adsorption and desorption, scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS). The use of the natural reducing agent Baccharis salicifolia resulted in nanoparticles with an average size of 31 nm. Furthermore, we showcase the application of the MCM-41@IONP nanocomposite in a metal–insulator–semiconductor (MIS) diode, which was fabricated at room temperature. The current–voltage and capacitance–voltage curves of the MIS diode were carefully measured and subjected to detailed analysis. The results demonstrate the potential utility of MCM-41@IONP nanocomposite-based MIS diodes, suggesting their applicability in the design of biosensors or as discrete components in electronic devices.

Applied Nano doi: 10.3390/applnano5020005

Authors: Donald C. Boone

This computational research study will compare the specific charge capacity (SCC) between lithium ions inserted into crystallized silicon (c-Si) nanowires with that of sodium ions inserted into amorphous silicon (a-Si) nanowires. It will be demonstrated that the potential energy V(r) within a lithium–silicon nanowire supports a coherent energy state model with discrete electron particles, while the potential energy of a sodium–silicon nanowire will be discovered to be essentially zero, and, thus, the electron current that travels through a sodiated silicon nanowire will be modeled as a free electron with wave-like characteristics. This is due to the vast differences in the electric fields of lithiated and sodiated silicon nanowires, where the electric fields are of the order of 1010 V/m and 10−15 V/m, respectively. The main reason for the great disparity in electric fields is the presence of optical amplification within lithium ions and the absence of this process within sodium ions. It will be shown that optical amplification develops coherent optical interactions, which is the primary reason for the surge of specific charge capacity in the lithiated silicon nanowire. Conversely, the lack of optical amplification is the reason for the incoherent optical interactions within sodium ions, which is the reason for the low presence of SCC in sodiated silicon nanowires.

Applied Nano doi: 10.3390/applnano5020004

Authors: Maria Paola Demichelis Agustina Mariana Portu Mario Alberto Gadan Agostina Vitali Valentina Forlingieri Silva Bortolussi Ian Postuma Andrea Falqui Elena Vezzoli Chiara Milanese Patrizia Sommi Umberto Anselmi-Tamburini

Nanoparticles composed of inorganic boron-containing compounds represent a promising candidate as 10B carriers for BNCT. This study focuses on the synthesis, characterization, and assessment of the biological activity of composite nanomaterials based on boron carbide (B4C). Boron carbide is a compelling alternative to borated molecules due to its high volumetric B content, prolonged retention in biological systems, and low toxicity. These attributes lead to a substantial accumulation of B in tissues, eliminating the need for isotopically enriched compounds. In our approach, B4C nanoparticles were included in composite nanostructures with ultrasmall superparamagnetic nanoparticles (SPIONs), coated with poly (acrylic acid), and further functionalized with the fluorophore DiI. The successful internalization of these nanoparticles in HeLa cells was confirmed, and a significant uptake of 10B was observed. Micro-distribution studies were conducted using intracellular neutron autoradiography, providing valuable insights into the spatial distribution of the nanoparticles within cells. These findings strongly indicate that the developed nanomaterials hold significant promise as effective carriers for 10B in BNCT, showcasing their potential for advancing cancer treatment methodologies.

Applied Nano doi: 10.3390/applnano5010003

Authors: Lei Li Shubin Yan Yang Cui Chuanhui Zhu Taiquan Wu Qizhi Zhang Guowang Gao

Based on the unique properties of optical Fano resonance and plasmonic-waveguide coupling systems, this paper explores a novel refractive index concentration sensor structure. The sensor structure is composed of a metal–insulator–metal (MIM) waveguide and two identically shaped and sized double-tooth ring couplers (DTR). The performance structure of the nanoscale refractive index sensor with DTR cavity was comprehensively assessed using the finite element method (FEM). Due to the impact of various geometric parameters on the sensing characteristics, including the rotation angles, the widths between the double-tooth rings, and the gaps between the cavity and the waveguide, we identified an optimal novel refractive index sensor structure that boasts the best performance indices. Finally, the DTR cavity sensor achieved a sensitivity of 4137 nm/RIU and Figure of merit (FOM) of 59.1. Given the high complexity and sensitivity of the overall structure, this nanoscale refractive index sensor can be applied to the detection of oil concentration in industrial oil–water mixtures, yielding highly precise results.

Applied Nano doi: 10.3390/applnano5010002

Authors: Sara Cerra Ilaria Fratoddi

Environmental pollution has become a pervasive and pressing issue in the modern world, mainly arising from human activities that release harmful substances into the air, water, and soil [...]

Applied Nano doi: 10.3390/applnano5010001

Authors: Beo Deul Ryu Hyeon-Sik Jang Kang Bok Ko Min Han Tran Viet Cuong Chel-Jong Choi Chang-Hee Hong

We synthesized a boron-doped reduced graphene oxide (BrGO) material characterized by various electrical properties, through simultaneous thermal reduction and doping procedures, using a metal–organic chemical vapor deposition technique. X-ray photoelectron spectroscopy (XPS) was used to study the impact of the doping level on the B bonding in the reduced graphene oxide (rGO) layer that is influenced by the annealing temperature. The synthesized BrGO layer demonstrated a high B concentration with a considerable number of O-B bonds, that were altered by annealing temperatures. This resulted in a decreased work function and the formation of a Schottky contact between the BrGO and n-type Si substrate. Due to the higher proportion of B-C and B-C3 bonding in the BrGO/Si device than that in the rGO/Si, the decreased Schottky barrier height of the BrGO/n-Si vertical junction photodetector resulted in a higher responsivity. This study showcases a promise of a simple B-doping method in use to alter the electrical characteristics of graphene materials.

Applied Nano doi: 10.3390/applnano4040017

Authors: Valerie Dürr Sabrina Wohlfart Tom Eisenzapf Walter Mier Gert Fricker Philipp Uhl

Lipid nanoparticles, including liposomes, have emerged as promising vehicles for the delivery of a variety of therapeutics. Several formulations have been approved and are used in medical practice—the COVID-19 mRNA vaccines represent the most recent milestone. Achieving effective oral delivery would elevate the potential of these formulations. Therefore, this study investigates the oral application of mRNA using liposomes as a nanocarrier system. A cyclic cell-penetrating peptide was coupled to the liposomal surface to allow uptake into the intestinal mucosal cells. The liposomes were loaded with mRNA (up to 112 µg/mL) and characterized in terms of their size (Z-average; 135.4 nm ± 1.1 nm), size distribution (polydispersity index (PDI); 0.213 ± 0.007 nm), surface charge (2.89 ± 0.27 mV), structure, lamellarity (multilamellar liposomes), and cargo capacity (>90%). The impact of freeze-drying and long-term storage of liposomal formulations was examined, and in vitro experiments on Caco-2 cells were conducted to evaluate the cytotoxicity of the liposomal formulations and demonstrate the uptake of the liposomes into cells. The efficiency of the formulations could be proven in vitro. When compared to control liposomes and 1,2-dioleoyl-3-trimethylammonium propane (DOTAP)-liposomes, the new formulations exhibited significantly enhanced uptake in Caco-2 cells, an immortalized epithelial cell line. Moreover, the cytocompatibility of the formulations could be proven by the absence of cytotoxic effects on the viability of Caco-2 cells. Hence, this liposomal drug delivery system holds significant promise for the oral delivery of mRNA.

Applied Nano doi: 10.3390/applnano4040016

Authors: Manohar Chirumamilla Tobias Krekeler Deyong Wang Peter K. Kristensen Martin Ritter Vladimir N. Popok Kjeld Pedersen

Aluminum nitride (AlN) is a material of growing interest for power electronics, fabrication of sensors, micro-electromechanical systems, and piezoelectric generators. For the latter, the formation of nanowire arrays or nanostructured films is one of the emerging research directions. In the current work, nanostructured AlN films manufactured with normal and glancing angle magnetron sputter depositions have been investigated with scanning and transmission electron microscopy, X-ray diffraction, atomic force microscopy, and optical spectroscopy. Growth of the nanostructures was realized utilizing metal seed particles (Ag, Au, and Al), allowing the control of the nucleation and following growth of AlN. It was demonstrated how variations of seed particle material and size can be used to tune the parameters of nanostructures and morphology of the AlN films. Using normal angle deposition allowed the growth of bud-shaped structures, which consisted of pillars/lamellae with wurtzite-like crystalline structures. Deposition at a glancing angle of 85° led to a film of individual nanostructures located near each other and tilted at an angle of 33° relative to the surface normal. Such films maintained a high degree of wurtzite-like crystallinity but had a more open structure and higher roughness than the nanostructured films grown at normal incidence deposition. The developed production strategies and recipes for controlling parameters of nanostructured films pave the way for the formation of matrices to be used in piezoelectric applications.

Applied Nano doi: 10.3390/applnano4030015

Authors: Sorour Darvishi Hubert H. Girault

This paper evaluated the use of soft-probe scanning electrochemical microscopy complementarily with confocal laser scanning microscopy to study the effects of different antimicrobial agents and treatments on E. coli DH5α biofilm. The antimicrobial agents were sodium azide, silver nanoparticles, and a flashlight. The effects of these agents were monitored by measuring the change in biofilm properties, such as biofilm biomass, live/dead studies, and surface activity. The results showed that sodium azide, silver nanoparticles, and the flashlight effectively killed E. coli biofilms and explained the mode of action for each treatment. Sodium azide was more effective in killing the biofilm after a short treatment time by blocking the ATPase, while silver nanoparticles were more effective at killing the biofilm after longer treatment times through several antibiofilm actions. This work showed that scanning electrochemical microscopy (SECM) is a very valuable tool for studying the effects of antimicrobial agents on biofilms. SECM is a sensitive technique that can be used to monitor the changes in biofilm properties in real-time. Additionally, SECM does not require any sample preparation, which makes it a convenient and efficient technique. Overall, the results of this study could be used to develop new strategies for treating E. coli biofilm infections and provide valuable insights into the use of SECM to study the effects of antimicrobial agents on E. coli biofilms.

Applied Nano doi: 10.3390/applnano4030014

Authors: Maria Paula Cardeal Volpi Gustavo Mockaitis Bruna de Souza Moraes

The present work proposes the optimization of the co-digestion of vinasse, filter cake, and deacetylation liquor in a continuous reactor by adding iron(III) oxide (Fe3O4) nanoparticles (NPs), comparing the results with a previous reactor operation without NPs. Initially, tests were carried out in batches with different NP concentrations, resulting in 5 mg L−1 as the best concentration to be added in the continuous reactor along the increments of the applied organic load rate (OLR). Methane (CH4) production reached a maximum value of 2.8 ± 0.1 NLCH4 gVS−1 (normal liter methane per gram of volatile solids), and the organic matter removal reached 71 ± 0.9% in phase VI (OLR of 5.5 gVS L−1 day−1). This production was 90% higher than the reactor co-digestion operation without NPs. The anaerobic digestion (AD) development was stable with stable organic acid (OA) concentrations, indicating the predominance of the propionic acid route to produce CH4. The main methanogenic Archaea identified was Methanoculleus, indicating that the predominant metabolic route was that of acetate (SAO) coupled with hydrogenotrophic methanogenesis. The use of Fe3O4 NPs managed to improve the AD from the first-generation and second-generation (1G2G) ethanol production residues and stimulated microbial community growth, without modifying the preferable metabolic pathways.

Applied Nano doi: 10.3390/applnano4030013

Authors: Phakamani H. Tsilo Albertus K. Basson Zuzingcebo G. Ntombela Nkosinathi G. Dlamini Rajasekhar V. S. R. Pullabhotla

Over recent years, the ‘green’ chemistry approach to synthesizing nanoparticles has made significant developments. Because of their unique features, nanoparticles have received a lot of attention. The use of a bioflocculant to promote the environmentally friendly synthesis of copper nanoparticles is described in this paper. Copper nanoparticles were biosynthesized using bioflocculant which was produced from a yeast, Pichia kudriavzevii. The chemical reduction approach was used to synthesize copper nanoparticles (CuNPs) using a bioflocculant as a capping agent. Characterization of the as-synthesized copper nanoparticles was conducted using Fourier transform infrared (FT-IR) spectroscopy, UV-visible spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and energy dispersive X-ray (EDX). The FT-IR spectra revealed characteristic peaks at 3267, 2956, 1656, 1059, and 511 cm−1 for the bioflocculant, while for the bioflocculant passivated CuNPs, the characteristic peaks were at 3482 (-OH), 3261, 1640, 1059, 580, and 519 cm−1 (Cu-O). These peaks revealed that functional groups such as hydroxyls, amines, and copper oxide bonds were present. The UV-Vis analysis showed surface plasmon resonance (SPR) at an absorbance range of 500–600 nm, with peak maxima at 555 and 575 nm for the as-synthesized CuNPs. The XRD pattern revealed planes such as (200) and (220) at 2θ = 43 and 52°, and the particle size (30 nm) was determined by the Debye–Scherrer equation. The transmission electron microscopy analysis revealed a spherical-shaped particle with an average size of 20 nm. The EDX analysis of the as-synthesized CuNPs revealed the presence of the element Cu, which was not present in the EDX image of the bioflocculant used in the synthesis of the CuNPs; this indicated the success of biosynthesis.

Applied Nano doi: 10.3390/applnano4030012

Authors: Nivaldo F. Andrade Neto Marisa C. Oliveira José Heriberto O. Nascimento Elson Longo Renan A. P. Ribeiro Mauricio R. D. Bomio Fabiana V. Motta

In this work, α-Ag2WO4 particles with different cross-sections were obtained using the co-precipitation method at different synthesis temperatures. The samples were characterized by X-ray diffraction (XRD), field-scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). The antimicrobial activity was analyzed using the Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) methods against the Escherichia coli and Salmonella spp. gram-negative bacteria. The antimicrobial tests against Escherichia coli and Salmonella spp. indicated that concentrations of 2.5–5 mg/mL and 5 mg/mL completely inhibit its growth, respectively. The antimicrobial activity was analyzed employing band-edge positions for ROS generations and the superficial distribution of Ag+ species that contribute to antimicrobial activity. Quantum-chemical calculations were used at the DFT level to investigate the surface-dependent reactivity of α-Ag2WO4, and we demonstrated how the antimicrobial properties could be tailored by the geometry and electronic structure of the exposed surfaces, providing guidelines for the morphology design.

Applied Nano doi: 10.3390/applnano4030011

Authors: Antonio Valadão Cardoso Clara Carvalho Souza Maria Sylvia Dantas Camila Schults Machado Erico Tadeu Freitas Alisson Krohling Veronica Martins Rosario Giancarlo Ubaldo Nappi Luiz Dias Heneine

Magnetite (Fe3O4) nanoparticles were extracted from the shells of freshwater Limnoperna fortunei (Dunker 1857) and marine Perna perna (Linnaeus 1758) mussels, followed by full physical and chemical characterization using ICP-OES, UV–Vis, EDX, Raman, and XRD spectroscopy, VSM magnetometry, and SEM and TEM techniques. Considering their spatial distribution, the ferrimagnetic particles in the shells had low concentration and presented superparamagnetic behavior characteristics of materials of nanometric size. Transmission electron microscopy (TEM, especially HRTEM) indicated round magnetic particles around 100 nm in size, which were found to be aggregates of nanoparticles about 5 nm in size. The TEM data indicated no iron oxide particles at the periostracum layer. Nevertheless, roughly round iron (hydr)oxide nanoparticle aggregates were found in the nacre, namely, the aragonite layer. As the aragonite layer is responsible for more than 97% of the shell of L. fortunei and considering the estimated size of the magnetic nanoparticles, we infer that these particles may be distributed homogeneously throughout the shell.

Applied Nano doi: 10.3390/applnano4020010

Authors: Ilya M. Gavrilin Yulia O. Kudryashova Maksim M. Murtazin Ilia I. Tsiniaikin Alexander V. Pavlikov Tatiana L. Kulova Alexander M. Skundin

This work demonstrates the possibility of electrochemical formation of Ge-Sn-O nanostructures from aqueous solutions containing germanium dioxide and tin (II) chloride at room temperature without prior deposition of fusible metal particles. This method does not require complex technological equipment, expensive and toxic germanium precursors, or binding additives. These advantages will make it possible to obtain such structures on an industrial scale (e.g., using roll-to-roll technology). The structural properties and composition of Ge-Sn-O nanostructures were studied by means of scanning electron microscopy and X-ray photoelectron spectroscopy. The samples obtained represent a filamentary structure with a diameter of about 10 nm. Electrochemical studies of Ge-Sn-O nanostructures were studied by cyclic voltammetry and galvanostatic cycling. Studies of the processes of lithium-ion insertion/extraction showed that the obtained structures have a practical discharge capacity at the first cycle ~625 mAh/g (specific capacity ca. 625 mAh/g). However, the discharge capacity by cycle 30 was no more than 40% of the initial capacity. The obtained results would benefit the further design of Ge-Sn-O nanostructures formed by simple electrochemical deposition.

Applied Nano doi: 10.3390/applnano4020009

Authors: Priscilla Barbosa Sales de Albuquerque Marthyna Pessoa de Souza Ana Isabel Bourbon Miguel A. Cerqueira Lorenzo Pastrana Paula Jauregi José A. Teixeira Maria das Graças Carneiro-da-Cunha

The objective of this work was to prepare different concentrations of liposomes based on lecithin containing quercetin, and evaluate their effect on the properties of galactomannan films obtained from Cassia grandis seeds. Quercetin-loaded lecithin liposomes (QT-LL) were obtained by the ethanol injection method by incorporating quercetin in different concentrations in a previously prepared suspension of lecithin liposomes in water. Following characterization of QT-LLs by zeta potential and dynamic light scattering, QT-LL with 75 µg quercetin/mL suspension was incorporated at different concentrations in galactomannan films. The films obtained were characterized for color, solubility, moisture content (MC), water vapor permeability (WVP), scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier-transform infrared (FTIR) spectroscopy. The size of lecithin liposomes with no quercetin was statistically than those containing quercetin above 50 µg/mL. All the QT-LLs presented a low polydispersity index, even considering their significant differences and similar values for zeta potential. The films displayed a rough surface and the galactomannan structure was confirmed by FTIR. Additionally, the amorphous nature of the polysaccharide was observed by XRD. The films were luminous, with a predominant yellow tendency and low opacity. The incorporation of QT-LL in galactomannan films did not lead to statistical differences for solubility and MC, while significant differences were observed for WVP. Galactomannan films were shown to be a promising structure for the incorporation of lecithin liposomes loaded with quercetin, pointing at promising applications for different applications.

Applied Nano doi: 10.3390/applnano4020008

Authors: Ayesha Kausar Ishaq Ahmad Tingkai Zhao

The design and necessity of corrosion-resisting nanocarbon nanocomposites have been investigated for cutting-edge aerospace applications. In this regard, nanocarbon nanofillers, especially carbon nanotubes, graphene, nanodiamond, etc. have been used to fill in various polymeric matrices (thermosets, thermoplastics, and conducting polymers) to develop anti-rusting space-related nanocomposites. This review fundamentally emphases the design, anti-corrosion properties, and application of polymer/nanocarbon nanocomposites for the space sector. An electron-conducting network is created in the polymers with nanocarbon dispersion to assist in charge transportation, and thus in the polymers’ corrosion resistance features. The corrosion resistance mechanism depends upon the formation of tortuous diffusion pathways due to nanofiller arrangement in the matrices. Moreover, matrix–nanofiller interactions and interface formation play an important role in enhancing the corrosion protection properties. The anticorrosion nanocomposites were tested for their adhesion, contact angle, and impedance properties, and NaCl tests and scratch tests were carried out. Among the polymers, epoxy was found to be superior corrosion-resisting polymer, relative to the thermoplastic polymers in these nanocomposites. Among the carbon nanotubes, graphene, and nanodiamond, the carbon nanotube with a loading of up to 7 wt.% in the epoxy matrix was desirable for corrosion resistance. On the other hand, graphene contents of up to 1 wt.% and nanodiamond contents of 0.2–0.4 wt.% were desirable to enhance the corrosion resistance of the epoxy matrix. The impedance, anticorrosion, and adhesion properties of epoxy nanocomposites were found to be better than those of the thermoplastic materials. Despite the success of nanocarbon nanocomposites in aerospace applications, thorough research efforts are still needed to design high-performance anti-rusting materials to completely replace the use of metal components in the aerospace industry.

Applied Nano doi: 10.3390/applnano4020007

Authors: Rasmiah Saad A. Almufarij Alaa El-Deen Ali Mohamed Elsayed Elba Howida Eid Okab Ollaa Moftah Mailoud Hamida Abdel-Hamid Howida Abouel Fetouh Elsayed

The purpose of this study is to modify all physicochemical properties of glycine–copper sulphate single crystals, such as crystal habits, molar mass, thermal stability, optical activity, and electrical properties. The novelty of this study is growth of glycine–copper sulphate single crystals doped by a low concentration of silver nanoparticles (SNPs) that improved both crystal habits and physicochemical properties. The originality of this work is that trace amounts of SNPs largely increased the crystal size. Crystals have molar stoichiometric formula [glycine]0.95, [CuSO4·5H2O]0.05 in the absence and presence of silver nanoparticles (SNPs) in different concentrations: 10 ppm, 20 ppm, and 30 ppm. The crystals’ names and abbreviations are: glycine–copper sulphate (GCS), glycine–copper sulphate doped by 10 ppm SNPs (GCSN1), glycine–copper sulphate doped by 20 ppm SNPs (GCSN2), and glycine–copper sulphate doped by 30 ppm SNPs (GCSN3). Dopant silver nanoparticles increased: crystallinity reflecting purity, transparency to UV-Vis. electromagnetic radiation, thermal stability, and melting point of glycine–copper sulphate single crystal. GCSN3 is a super conductor. High thermal conductivity of crystals ranging from 1.1 W·min−1·K−1 to 1.6 W·min−1·K−1 enabled attenuation of electromagnetic radiation and rapid heat dissipation due to good dielectric and polar properties. On rising temperature, AC electrical conductivity and dielectric properties of perfect crystal GCSN3 increased confirmed attenuation of thermal infrared radiation.

Applied Nano doi: 10.3390/applnano4020006

Authors: Ghasan Fahim Huseien

The demand of high performance and environmentally sustainable construction materials is ever-increasing in the construction industry worldwide. The rapid growth of nanotechnology and diverse nanomaterials’ accessibility has provided an impulse for the uses of smart construction components like nano-alumina, nano-silica, nano-kaolin, nano-titanium, and so forth Amongst various nanostructures, the core-shell nanoparticles (NPs) have received much interests for wide applications in the field of phase change materials, energy storage, high performance pigments, coating agents, self-cleaning and self-healing systems, etc., due to their distinct properties. Through the fine-tuning of the shells and cores of NPS, various types of functional materials with tailored properties can be achieved, indicating their great potential for the construction applications. In this perception, this paper overviewed the past, present and future of core-shell NPs-based materials that are viable for the construction sectors. In addition, several other applications of the core-shell NPs in the construction industries are emphasized and discussed. Considerable benefits of the core-shell NPs for pigments, phase change components, polymer composites, and self-cleaning glasses with enhanced properties are also underlined. Effect of high performance core-shell NPs type, size and content on the construction materials sustainability are highlighted.

Applied Nano doi: 10.3390/applnano4020005

Authors: Li Gao Bin Li

The present work reports the preparation of gardenia yellow pigment containing paraffin oil nanoemulsions stabilized by Span80 and Tween80. The preparation of the required nanoemulsions was optimized by testing different conditions, such as varying the hydrophilic–lipophilic balance (HLB), the emulsifier concentration (EC), the oil–water ratio (OWR), and the temperature (T), as determined by the average droplet diameter (ADD) and polydispersity index (PDI). Our results indicated that a minimum ADD of 65.9 nm and PDI of 0.116 were obtained at an optimum HLB value of 6.0, EC of 10% (w/w), OWR of 2:1, and T of 40 °C. Both the steady-state and dynamic rheological parameters were further investigated, revealing that the emulsions exhibited pseudoplastic behaviors. The long-term stabilities of the nanoemulsions after the addition of inorganic salts were monitored by observing their visual appearances. It was found that the emulsions containing pure water or 0.1 M CaCl2 and AlCl3 became slightly separated, while the emulsions containing 0.1 M KCl and NaCl showed no separation after 30 days of storage at room T. This difference among different salts could be related to the number of valence electrons of their cations. The spatial electrostatic effects of the monovalent cationic (KCl and NaCl) and the nonionic surfactants were greater than the delamination/sedimentation forces of the system, which was better than the salt based on the cations with valences greater than one (CaCl2 and AlCl3). In conclusion, the present work illustrated the formation, rheological properties, and stability of water containing gardenia yellow pigment in paraffin oil nanoemulsions, which can be of great significance for the application of gardenia-yellow-pigment-based formulations.

Applied Nano doi: 10.3390/applnano4010004

Authors: Carolina Sbarigia Simone Dinarelli Francesco Mura Luca Buccini Francesco Vari Daniele Passeri Marco Rossi Stefano Tacconi Luciana Dini

Extracellular vesicles (EVs) are important mediators of intercellular communication in several physiopathological conditions. Oxidative stress alters EVs release and cargo composition depending on the cell type and stimulus. Recently, most of the EVs studies have focused on the characterization of their cargo, rather than on the morphological features (i.e., size distribution, shape, and localization on the cell surface). Due to their high heterogeneity, to fully characterize EVs both the functional and morphological characterization are required. Atomic force microscopy (AFM), introduced for cell morphological studies at the nanoscale, represents a promising method to characterize in detail EVs morphology, dynamics along the cell surface, and its variations reflecting the cell physiological status. In the present study, untreated or H2O2-treated wild-type and SOD1-G93A SH-SY5Y cells have been compared performing a transmission electron microscopy (TEM) and AFM morpho-quantitative analysis of budding and released vesicles. Intriguingly, our analysis revealed a differential EVs profiling, with an opposite behavior and implying different cell areas between WT and SOD1-G93A cells, on both physiological conditions and after H2O2 exposure. Our results empower the relationship between the morphological features and functional role, further proving the efficacy of EM/AFM in giving an overview of the cell physiology related to EVs trafficking.

Applied Nano doi: 10.3390/applnano4010003

Authors: Robert Browning Paul Plachinda Raj Solanki

MoP is a topological semimetal which has drawn attention due to its unique electrical and optical properties resulting from massless electrons. In order to utilize these properties for practical applications, it is necessary to develop a technique to produce high-quality, large-scale thin films of this 2D material. We report below our initial results of growth of MoP thin films using atomic layer deposition (ALD), where the film grows layer-by-layer. These films were grown on 5 cm × 5 cm silicon oxide coated Si wafers. Resistivity versus temperature measurements show that these films are metallic and includes a partial superconducting phase. The magnetoresistances of both the longitudinal and Hall currents measured at 1.8 K show a strong effect of the magnetic field on the resistivity. Density functional theory was employed to determine the lattice constants of the MoP crystal. These parameters were in good agreement with those obtained from the Rietveld fit to the XRD spectrum of the films.

Applied Nano doi: 10.3390/applnano4010002

Authors: Eugene E. Nazarov Oleg A. Tyablikov Victoria A. Nikitina Evgeny V. Antipov Stanislav S. Fedotov

Carbon-coating proved an efficient and reliable strategy to increase the power capabilities and lifetime of phosphate-based positive electrode materials for Li-ion batteries. In this work, we provide a systematic study on the influence of polyacrylonitrile-(PAN)-derived carbon coating on electrochemical properties of the nanosized Li-rich Li1+δ(Fe0.5Mn0.5)1−δPO4 (Li-rich LFMP) cathode material, as well as the characterization of carbon-coated composites by means of Raman spectroscopy for the determination of carbon graphitization degree, DF-STEM and STEM-EELS for the estimation of carbon layer thickness, uniformity and compositional homogeneity of the conductive layer respectively, and impedance spectroscopy for the determination of charge transfer resistances of the resulted composite electrodes in Li-based cells. Using PAN as a carbon coating precursor enables significantly enhancing the cycling stability of Li-rich LFMP/C compared to those conventionally obtained with the glucose precursor: up to 40% at high current loads of 5–10C retaining about 78 ± 2% of capacity after 1000 cycles. Varying the PAN-derived carbon content in the composites allows controlling the electrochemical response of the material triggering either a high-capacity or a high-power performance.

Applied Nano doi: 10.3390/applnano4010001

Authors: Nkosinathi Goodman Dlamini Albertus Kotze Basson Viswanadha Srirama Rajasekhar Pullabhotla

Bimetallic nanoparticles are a complex nanoscale combination of two metal constituents. The superior properties of bimetallic nanoparticles (BNPs) compared with monometallic nanoparticles have attracted much attention from both scientific and technological perspectives. In recent years, many fabrication techniques have been proposed, and the detailed characterization of bimetallic nanoparticles has been made possible by the rapid advancement of nanomaterial analysis techniques. Metallic nanoparticles can be classified according to their origin, size, and structure, and their synthesis process can be physical, chemical, or biological. Bimetallic nanoparticles are more attractive than metal nanoparticles due to their unique mixing patterns and synergistic effects of two metal nanoparticles forming the bimetal. In this review, the different bimetallic synthesis methods and various characterization techniques are discussed. The paper will also discuss various applications for bimetallic nanoparticles. Different characterization techniques for bimetallic nanoparticles include X-ray diffraction (XRD) to investigate crystallinity and phase composition; the morphology and composition analysis of nanoparticles are studied using a scanning electron microscope fitted with an energy-dispersive X-ray analyzer (EDX); transmission electron microscopy (TEM), UV–vis spectrum, FTIR, and TGA analysis are also among the characterization tools used. Finally, we report on the various applications of BNPs, which include antimicrobial activity, pollutant removal, and wastewater application.

Applied Nano doi: 10.3390/applnano3040016

Authors: Kyle Culhane Viktoriia Savchuk Anatoliy O. Pinchuk Kelly McNear

Due to their biocompatibility, ease of surface modification, and heating capabilities, gold nanomaterials are considered excellent candidates for the advancement of photothermal therapy techniques and related applications in cancer treatment. Various morphologies of gold nanomaterials have been shown to heat when exposed to high-powered laser irradiation, especially that which is from the near-infrared (NIR) region. While these lasers work well and are effective, light-emitting diodes (LEDs) may offer a safe and low-powered alternative to these high energy lasers. We investigated the heating capability of NIR-dye conjugated gold nanorods when exposed to an 808 nm LED light source using polyethylene glycol (PEG)-coated gold nanorods as the control. In this way, since the rods exhibited a surface plasmon resonance peak between 795 and 825 nm for both the PEG-coated rods and the dye-conjugated rods, which are fairly close to the frequency of the 530 mW, 850 nm LED light source, we were able to reveal the heating effect of the dye modification. While both morphologies heat when irradiated with the LED light, we demonstrated that the addition of an NIR dye increases the rate of heating and cooling, compared to the PEGylated counterpart. To our knowledge, the complementary effect given by the conjugated NIR-dye has not been previously reported in the literature. The targeting abilities of the NIR-dye combined with the increased heating rate of the modified particles used in this proof-of-concept work suggests that these particles may be exceptional candidates for theranostic applications.

Applied Nano doi: 10.3390/applnano3040015

Authors: Ganesan Padmini Tamilarasi Manikandan Krishnan Govindaraj Sabarees Siddan Gouthaman Veerachamy Alagarsamy Viswas Raja Solomon

Chronic wounds impose a significant burden on individuals and healthcare systems all over the world. Through clinical and preclinical investigations, inflammation and oxidative damage have been established as the primary causes of chronic wounds. These skin sores are easily exposed to microorganisms, which in turn cause inflammation and hinder the healing process. Additionally, microorganisms may cause an infection that prevents collagen production and reepithelialization. Curcumin’s antioxidant, anti-inflammatory, and anti-infectious characteristics, among others, have been identified as useful for diabetic wound healing management. However, curcumin has a few disadvantages, such as limited bioavailability, pH-dependent instability, water insolubility, slow cell absorption, and fast intracellular metabolism. These constraints necessitates the development of a suitable transporter to improve curcumin’s stability, bioavailability, therapeutic efficacy, and solubility. In recent years, Electrospun nanofiber mats have been an excellent choice for drug delivery because of their numerous advantages and inherent properties. Electrospun nanofibers have shown considerable promise as wound dressing materials. This review highlights the potential properties and recent advancements in using curcumin-loaded nanofibers for diabetic wound healing.

Applied Nano doi: 10.3390/applnano3040014

Authors: Terrence Ravine Qunying Yuan Makenna Howell

Biogenic silver nanoparticles (b-AgNPs) were produced extracellularly using a cell lysate of genetically modified Escherichia coli and subdivided into three groups. Each group received a different treatment to determine which one best removed residual cell lysate material. The first group was treated twice using only water (water ×2), the second using 8M urea once (8M urea ×1), and the third using 8M urea twice (8M urea ×2). Subsequently, each group was assessed for its ability to inhibit the growth of six bacterial and two fungal pathogens. Testing was accomplished using the minimum inhibitory concentration (MIC) method. Commercially produced c-AgNPs were included for comparison. In all cases, the b-AgNPs (8M urea ×2) demonstrated the greatest inhibition of microbe growth. Conversely, the commercial AgNPs failed to show any growth inhibition at 10 µg/mL the highest concentration tested. The greater antibacterial activity of the b-AgNPs (8M urea ×2) over both b-AgNPs (8M urea ×1) and b-AgNPs (water ×2) is thought to be due to a larger degree of biofunctionalization (coating) occurring during the two sequential 8M urea treatments.

Applied Nano doi: 10.3390/applnano3030013

Authors: Vinayak Sharma Bilal Javed Hugh Byrne James Curtin Furong Tian

The world is facing immense challenges in terms of food security, due to the combined impacts of the ever-increasing population and the adversity of climate change. In an attempt to counteract these factors, smart nutrient delivery systems, including nano-fertilizers, additives, and material coatings, have been introduced to increase food productivity to meet the growing food demand. Use of nanocarriers in agro-practices for sustainable farming contributes to achieving up to 75% nutrient delivery for a prolonged period to maintain nutrient availability in soil for plants in adverse soil conditions. In this context, sieve-like zeolites and the diversity in their structural morphologies have attracted increasing interest over recent years. Engineered nano-porous zeolites, also called aluminosilicates, are defined based on the presence of micro- (<2 nm), meso- (2–50 nm), and macropores (>50 nm), which can be employed as carriers of fertilizers due to their enhanced ion-exchange properties and adsorption capabilities. In this study, we provide a detailed overview of the production and optimization of hierarchical zeolite structures within the size range from micro- to nanometers, as well as the various top-down and bottom-up approaches which have been used to synthesize zeolites with a large surface area, tunable pore size, and high thermal stability, which make them an excellent candidate to be used in agronomy. The delivery of pesticides, insecticides, and fertilizers by loading them into nano-zeolites to manage the crop production without disrupting the soil health is discussed, as well as future perspectives of zeolites in the perpetual maintenance of soil productivity.

Applied Nano doi: 10.3390/applnano3030012

Authors: Dimitrios N. Bikiaris

Polymer nanocomposites are an emerging technological field offering high-performance materials with unique and innovative properties, ideal for numerous advanced applications [...]

Applied Nano doi: 10.3390/applnano3030011

Authors: Noelia Losada-Garcia Alba Rodriguez-Otero Clara Ortega-Nieto Ariane Azarmi Jose M. Palomo

In this work, an efficient synthesis of bionanohybrids as artificial metalloenzymes (Cu, Pd, Ag, Mn) based on the application of an enzyme as a scaffold was described. Here we evaluated the effect of changing the metal, pH of the medium, and the amount of enzyme in the synthesis of these artificial metalloenzymes, where changes in the metal species and the size of the nanoparticles occur. These nanozymes were applied in the degradation of hydrogen peroxide for their evaluation as mimetics of catalase activity, the best being the Mn@CALB-H2O, which presented MnO2 nanostructures, with three-fold improved activity compared to Cu2O species, CuNPs@CALB-P, and free catalase.

Applied Nano doi: 10.3390/applnano3030010

Authors: Anjul Khadria Subhankar Paul

Gold nanoparticles have been increasingly used in several electronic, material fabrication, and biomedical applications. Several methods have been reported to prepare gold nanoparticles of various shapes and sizes with different photophysical properties. Although useful to prepare gold nanoparticles, most of the methods are not stable enough, which leads to the degradation of the nanoparticles, if they are stored at room temperatures (up to 30 °C) for a few days. In this paper, we report a novel and environmentally friendly method to synthesize self-assembled gold nanoparticles in cruciform shapes by using leaf extract of Cannabis indica as a reducing agent without the aid of any polymers or additional chemicals. The nanoparticles are found to be stable for more than a month (45 days) when stored at room temperature (up to 30 °C). They were able to form stable conjugates with bovine α-lactalbumin protein that may possess anti-cancerous properties.

Applied Nano doi: 10.3390/applnano3030009

Authors: Paulo R. Oliveira-Pinto Nuno Mariz-Ponte Renato L. Gil Edite Cunha Célia G. Amorim Maria C. B. S. M. Montenegro Manuel Fernandes-Ferreira Rose M. O. F. Sousa Conceição Santos

Bacterial spot (BS) of tomato (S. lycopersicum), caused by Xanthomonas spp., namely X. euvesicatoria (Xeu), is one of the major threats for the production of this crop worldwide. Developing new biocontrol solutions against this disease will allow disease management strategies to be less based on Cu compounds. Nanoclays, such as montmorillonite (NMT), have been under investigation for their antimicrobial activity, or as delivery tools/stabilizers for organic compounds, such as essential oils (EOs), that also possess antimicrobial activity against plant pathogens. This work aims to assess how the application of NMT alone or incorporating S. montana EO on Xeu-infected hosts (var. Oxheart) affects the shoots’ redox status and antioxidant defense mechanisms. In vitro shoots, grown on Murashige and Skoog medium, were divided in two groups, Xeu-infected and uninfected (control) shoots. Shoots of each group were then treated with NMT, S. montana EO, EO-NMT. Results show that the NMT was able to reduce Xeu bacterial amount, while reducing ROS production and keeping the transcript levels of the defense-related genes close to those of the control. When applied to uninfected shoots, the treatments triggered the production of ROS and upregulated the phenylpropanoid and hormone pathway, which suggest that they act as defense elicitors. Globally, the results indicate that NMT has the potential to integrate BS management strategies, due to its antimicrobial activity, and that EO and/or nanoclays could be successfully employed as new disease preventive strategies, since they enhance the healthy shoots’ defense, thus potentially limiting the pathogen establishment.

Applied Nano doi: 10.3390/applnano3020008

Authors: Rohini Atluri Daniel Korir Tae-Youl Choi Denise Perry Simmons

Glioblastoma multiforme is an aggressive, invasive, fatal primary heterogenic brain tumor. New treatments have not significantly improved the dismal survival rate. Low-level laser therapy reports indicate different tumor cells respond distinctly to low-level laser therapy based on laser dose (J/cm2) or with nanotherapeutics. We investigated the effects of pairing two optical property-driven treatment agents—a low-level laser on glioblastoma multiforme (U251) using an He-Ne laser (632.8 nm) with 18.8 nm spherical Ag-PMMA-PAA nanoparticles, with an absorbance peak at 400 nm with a broad shoulder to 700 nm. The He-Ne treatment parameters were power (14.87 ± 0.3 mW), beam diameter (0.68 cm), and exposure time 5 min leading to a 12.28 J/cm2 dose. A dose of 12.28 J/cm2 was applied to Ag-PMMA-PAA nanoparticle concentrations (110–225 μM). An amount of 110 μM Ag-PMMA-PAA nanoparticles combined with an He-Ne dose at 18 h yielded 23% U251 death compared to He-Ne alone which yielded 8% U251 death. A 225 μM Ag-PMMA-PAA nanoparticle He-Ne combination resulted in an earlier, more significant, U251 death of 38% at 6 h compared to 30% with 225 μM alone at 18 h. Both treatment agents possess inherent physical and functional properties capable of redesign to enhance the observed cell death effects. Our results provide evidence supporting next-step studies to test “the redesign hypothesis” that these paired optical-driven agents provide a tunable platform that can generate significant U251 cell death increase.

Applied Nano doi: 10.3390/applnano3020007

Authors: Francesco Zamboni Arūnė Makarevičiūtė Vladimir N. Popok

Coinage metal nanoparticles (NPs) are well-known for the phenomenon of localized surface plasmon resonance (LSPR), which is widely utilized for enhanced sensing and detection. LSPR stability over time is an important issue for the practical application of nanoparticle matrices. Some metals, and copper among those, are chemically reactive in ambient atmospheric conditions that leads to degradation of plasmonic functionality. This work reports on the formation of Cu NP matrices utilizing magnetron-sputtering gas-phase aggregation, size-selection and soft-landing on a substrate. This method provides monocrystalline NPs with high purity, thus, improving chemical inertness towards ambient gases, for example, oxygen. Additionally, a simple approach of UV-ozone treatment is shown to form an oxide shell protecting the metallic core against reactions with environmental species and stabilizing the plasmonic properties for a period of over 150 days. The suggested methodology is promising to improve the competitiveness of Cu nano-matrices with those of Au and Ag in plasmonic sensing and detection.

Applied Nano doi: 10.3390/applnano3020006

Authors: Xinyi Zhao Hugh J. Byrne Christine M. O’Connor James Curtin Furong Tian

Mycotoxins are secondary metabolic products of fungi. They are poisonous, carcinogenic, and mutagenic in nature and pose a serious health threat to both humans and animals, causing severe illnesses and even death. Rapid, simple and low-cost methods of detection of mycotoxins are of immense importance and in great demand in the food and beverage industry, as well as in agriculture and environmental monitoring, and, for this purpose, lateral flow immunochromatographic strips (ICSTs) have been widely used in food safety and environmental monitoring. The literature to date describing the development of ICSTs for the detection of different types of mycotoxins using different nanomaterials, nanoparticle size, and replicates was reviewed in an attempt to identify the most important determinants of the limit of detection (LOD). It is found that the particle size and type of materials contribute significantly to determining the LOD. The nanoparticle sizes used in most studies have been in the range 15–45 nm and gold nanoparticle-based ICSTs have been shown to exhibit the lowest LOD. Perspectives for potential future development to reduce the LODs of ICSTs are also discussed.

Applied Nano doi: 10.3390/applnano3010005

Authors: Ramona Kuhn Isaac Mbir Bryant Robert Jensch Jörg Böllmann

Today, nanotechnologies (NTs) are well established in both private households and commercial markets. NTs are fully accepted in several sectors, such as medicine and pharmacy, and in industries, such as chemistry, electricity, food production, military, and other commercial branches, due to their unique properties. With regard to the growing demands for environmental resources caused by the still-growing global population, the application of NTs is an extremely important new branch in the environmental sector, delivering several advantages. Our review provides a comprehensive overview of the current developments in environmental remediation, wastewater treatment, drinking water treatment, and agriculture. More specifically, in the section on environmental remediation, we review the application of NTs towards enhanced reductive dechlorination, removal of heavy metals and remediation of oil spills. In the section on wastewater treatment, we highlight developments in the adsorption of heavy metals and persistent substances, advanced photocatalytic degradation of common wastewater pollutants, and improvements in membrane filtration processes. In the section on drinking water treatment, we discuss applications for the enhanced disinfection of pathogens, removal of heavy metals, point-of-use treatments, and the removal of organic matter. In the final section, on agriculture, we provide an overview of precision farming and the current state of the art concerning nanofertilisers, nanopesticides, nanoherbicides, and nano(bio)sensors.

Applied Nano doi: 10.3390/applnano3010004

Authors: Arnith Eechampati Chamaree de Silva

Optical tweezers have been a fixture of microscopic cell manipulation since the 1990s. Arthur Ashkin’s seminal work has led to the advancement of optical tweezers as an effective tool for assay development in the fields of physics and nanotechnology. As an advanced application of cell manipulation, optical tweezers have facilitated the study of a multitude of cellular and molecular interactions within the greater field of nanotechnology. In the three decades since the optical tweezers’ rise to prominence, different and versatile assays have emerged that further explore the biochemical pathways integral for cell proliferation and communication. The most critical organelle implicated in the communication and protection of single cells includes the plasma membrane. In the past three decades, novel assays have emerged which examine the plasma membrane’s role in cell-to-cell interaction and the specific protein components that serve integral membrane functions for the cell as a whole. To further understand the extent to which optical tweezers have evolved as a critical tool for cellular membrane assessment within the field of nanotechnology, the various novel assays, including pulling, indentation, and stretching assays, will be reviewed in the current research sector.

Applied Nano doi: 10.3390/applnano3010003

Authors: Applied Nano Editorial Office Applied Nano Editorial Office

Rigorous peer-reviews are the basis of high-quality academic publishing [...]

Applied Nano doi: 10.3390/applnano3010002

Authors: Aurimas Kopūstas Mindaugas Zaremba Marijonas Tutkus

Protein-DNA interactions are the core of the cell’s molecular machinery. For a long time, conventional biochemical methods served as a powerful investigatory basis of protein-DNA interactions and target search mechanisms. Currently single-molecule (SM) techniques have emerged as a complementary tool for studying these interactions and have revealed plenty of previously obscured mechanistic details. In comparison to the traditional ones, SM methods allow direct monitoring of individual biomolecules. Therefore, SM methods reveal reactions that are otherwise hidden by the ensemble averaging observed in conventional bulk-type methods. SM biophysical techniques employing various nanobiotechnology methods for immobilization of studied molecules grant the possibility to monitor individual reaction trajectories of biomolecules. Next-generation in vitro SM biophysics approaches enabling high-throughput studies are characterized by much greater complexity than the ones developed previously. Currently, several high-throughput DNA flow-stretch assays have been published and have shown many benefits for mechanistic target search studies of various DNA-binding proteins, such as CRISPR-Cas, Argonaute, various ATP-fueled helicases and translocases, and others. This review focuses on SM techniques employing surface-immobilized and relatively long DNA molecules for studying protein-DNA interaction mechanisms.

Applied Nano doi: 10.3390/applnano3010001

Authors: Nikolaos D. Bikiaris Ioanna Koumentakou Smaro Lykidou Nikolaos Nikolaidis

In the present study, oil-in-water (O/W) sunscreen emulsions were prepared containing different portions of lignin (LGN), multiwall carbon nanotubes (MWCNTs) and graphene oxide (GO) nanoadditives. The stability in terms of pH and viscosity of emulsions was thoroughly studied for up to 90 days, exhibiting high stability for all produced O/W emulsions. The antioxidant activity of emulsions was also analyzed, presenting excellent antioxidant properties for the emulsion that contains LGN due to its phenolic compounds. Moreover, the emulsions were evaluated for their ultraviolet (UV) radiation protection ability in terms of sun protection factor (SPF) and UV stability. SPF values varied between 6.48 and 21.24 while the emulsion containing 2% w/v MWCNTs showed the highest SPF index and all samples demonstrated great UV stability. This work hopefully aims to contributing to the research of more organic additives for cosmetic application with various purposes.

Applied Nano doi: 10.3390/applnano2040026

Authors: Victor G. Zavodinsky Olga A. Gorkusha

In the context of a full-potential orbital-free approach for the modeling of multi-atomic systems we investigated the dependence of the cohesive energies and bulk elastic modules of the large nanosystems Cn (n is up to 4096 atoms), Aln (n is up to 23,328 atoms) and tin (n is up to 2160 atoms). It was shown that the cohesive energies and elastic modules tend towards bulk crystal values at n ≈ 3000 for Cn systems, at n ≈ 1500 for Tin and at n ≈ 20,000 for Aln. The execution time for one energy iteration for Ti23328 was only 23 min.

Applied Nano doi: 10.3390/applnano2040025

Authors: Daiana A. Bravo Fuchineco Angélica C. Heredia Sandra M. Mendoza Enrique Rodríguez-Castellón Mónica E. Crivello

The massive use of petroleum and its possible exhaustion are driving the current research trend to study alternative raw materials from biomass for organic reactions. In this context, the present article presents a study of the catalytic esterification of levulinic acid, a platform molecule, with ethanol. Metal-organic framework (MOF) type compounds UiO-66-NH2 have been synthesized. Zirconium was incorporated, using zirconium chloride as a metal precursor, together with 2-aminoterephthalic acid as an organic binding agent. An alternative route of synthesis was proposed using more favorable conditions from an economic and environmental point of view, replacing dimethylformamide by 50 and 75% acetone as substitute solvent. The physicochemical properties of the materials were evaluated by X-ray diffraction (XRD), Infrared Spectrometry with Fourier Transform (FTIR), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), microwave plasma atomic emission spectroscopy (MP-AES) and N2 adsorption to understand their morphology, crystalline, chemical and pore structure. The progress of the reaction was followed by gas chromatography and mass spectroscopy. The catalytic activity result of MOF25% in autoclave reactor, showed 100% of selectivity to ethyl levulinate and a turnover number (TON) of 66.18 moles of product/moles of Zr. This good catalytic performance obtained by partial solvent replacement in the synthetic material provides a more economical and eco-friendly process for ethyl levulinate generation.

Applied Nano doi: 10.3390/applnano2040024

Authors: Céline Henoumont Gauthier Hallot Estelle Lipani Catherine Gomez Robert N. Muller Luce Vander Elst Marc Port Sophie Laurent

NMR is a powerful characterization tool and we propose to study the surface of silica or bismuth nanoparticles dedicated to medical applications in order to evidence the covalent grafting of organic molecules on their surface. For that aim, DOSY experiments are particularly useful and allow for the discrimination of molecules interacting strongly with the nanoparticle surface from molecules simply weakly adsorbed at the surface. We were able to characterize thoroughly the surface of different silica and bismuth nanoparticles.

Applied Nano doi: 10.3390/applnano2040023

Authors: Laurent Gravier Yves Salvadé Damien Pidoux Julien Maritz Marco Laratta

We report here the feasibility study of anti-counterfeiting low-cost nanostructured flexible security tags for the tracking of large-scale fabrication products, such as pharmaceuticals or original equipment manufacturers. The fabrication process makes use of the mature nanotechnology called Template Synthesis to shape thin track-etched polymer film into covert laser readable tags, combining random self-organized structures with organized patterns. Techniques are developed to drastically limit the number of fabrication steps and keep fabrication costs low, while opening to numerous adjustment parameters. A dedicated, simple optical setup is presented, to capture speckle images of such tags lightened up by light emitting diodes or laser beams. Speckle images are analyzed in terms of encoding parameters, found here quite numerous to ensure a large coding range of large-scale production batches. We particularly highlight ultra-dark areas in speckle images, where nanowire structures completely inhibit speckle patterns. This unique, high-contrast optical feature addresses these low-cost nanostructured thin films to provide a very promising solution for large-scale security tags.

Applied Nano doi: 10.3390/applnano2040022

Authors: Ayyappan Elangovan Jiayi Xu Archana Sekar Sabari Rajendran Bin Liu Jun Li

Nitrogen doping in carbon materials can modify the employed carbon material’s electronic and structural properties, which helps in creating a stronger metal-support interaction. In this study, the role of nitrogen doping in improving the durability of Pt catalysts supported on a three-dimensional vertically aligned carbon nanofiber (VACNF) array towards oxygen reduction reaction (ORR) was explored. The nitrogen moieties present in the N-VACNF enhanced the metal-support interaction and contributed to a reduction in the Pt particle size from 3.1 nm to 2.3 nm. The Pt/N-VACNF catalyst showed better durability when compared to Pt/VACNF and Pt/C catalysts with similar Pt loading. DFT calculations validated the increase in the durability of the Pt NPs with an increase in pyridinic N and corroborated the molecular ORR pathway for Pt/N-VACNF. Moreover, the Pt/N-VACNF catalyst was found to have excellent tolerance towards methanol crossover.

Applied Nano doi: 10.3390/applnano2040021

Authors: Adrianna Glinkowska Mares Natalia Feiner-Gracia Yolanda Muela Gema Martínez Lidia Delgado Lorenzo Albertazzi Silvia Pujals

Organ-on-a-chip technology is a 3D cell culture breakthrough of the last decade. This rapidly developing field of bioengineering intertwined with microfluidics provides new insights into disease development and preclinical drug screening. So far, optical and fluorescence microscopy are the most widely used methods to monitor and extract information from these models. Meanwhile transmission electron microscopy (TEM), despite its wide use for the characterization of nanomaterials and biological samples, remains unexplored in this area. In our work we propose a TEM sample preparation method, that allows to process a microfluidic chip without its prior deconstruction, into TEM-compatible specimens. We demonstrated preparation of tumor blood vessel-on-a-chip model and consecutive steps to preserve the endothelial cells lining microfluidic channel, for the chip’s further transformation into ultrathin sections. This approach allowed us to obtain cross-sections of the microchannel with cells cultured inside, and to observe cell adaptation to the channel geometry, as well as the characteristic for endothelial cells tight junctions. The proposed sample preparation method facilitates the electron microscopy ultrastructural characterization of biological samples cultured in organ-on-a-chip device.

Applied Nano doi: 10.3390/applnano2030020

Authors: Nancy Brodie-Linder Johnny Deschamps Marianne Bombled Nicolas Pasternak Fabrice Audonnet Patricia Beaunier Christiane Alba-Simionesco

A new and simple method for preparing confined copper and nickel nanoparticles by thermal treatment of their respective cations inside Mobil Composition of Matter 41 (MCM–41) hydrophobic nanopores is presented here. Surface modified MCM–41 hydrophobic materials were impregnated by using high-pressure treatment with copper II (Cu II) or nickel II (Ni II) aqueous solutions. After pressure release and washing, the remaining metal cations, confined exclusively within the nanopores, were heated, forming metallic nanoparticles. Reduction of the cations by a redox reaction between the hydrophobic organic surface and the confined metal cations is proposed. Transmission electronic microscopy (TEM), selected area electron diffraction (SAED), nitrogen (N2) adsorption at −196 °C (77 K), Fourier transform infrared (FTIR) and thermogravimetric (TGA) analyses evidenced the identification of copper and nickel nanoparticles (NPs).

Applied Nano doi: 10.3390/applnano2030019

Authors: Jin Hee Kim Jong Hun Han Jae-Hyung Wee Go Bong Choi Seungki Hong Yoong Ahm Kim

Multiple heteroatom-doped graphene is of great interest for developing an efficient electrocatalyst for oxygen reduction reaction (ORR). To maximize the electrocatalytic performance of doped graphene, the competitive doping mechanism caused by the different atomic sizes of dopants should be developed. Herein, three different heteroatoms (e.g., N, P and B) are competitively introduced into reduced graphene oxide (RGO) using both single- and two-step processes. The total quantity of heteroatoms for ternary RGO synthesized using the two-step process is lower than that when using the single-step process. Higher ORR electrocatalytic activity for the two-step-synthesized RGO compared to the single-step-synthesized RGO can be explained by: (a) a high amount of P atoms; (b) the fact that B doping itself decreases the less electrocatalytic N moieties such as pyrrole and pyridine and increases the high electrocatalytic moieties such as quaternary N; (c) a high amount of B atoms itself within the RGO act as an electrocatalytic active center for O2 adsorption; and (d) a small amount of substitutional B might increase the electrical conductivity of RGO. Our findings provide new insights into the design of heteroatom-doped carbon materials with excellent electrocatalytic performance.