Maslinic acid (MA), a triterpene widely found in natural sources, is a compound which is gaining interest due to its multiple therapeutic activities and its lack of harmful effects. However, MA is practically insoluble in water, which limits its clinical application. Here, we present a solvent displacement method to produce MA Solid Lipid Nanoparticles (SLNs) as a nanoplatform to carry hydrophobic drugs. A systematic study of the experimental parameters that may have some influence on the colloidal characteristics of MA SLNs was carried out. The effect of the aqueous/organic phase volume ratio and the organic phase composition on the size of SLNs evidence the role of the solvent diffusivity on the colloidal characteristic of the SLNs. On the other hand, the effect of surfactant/MA ratio proved the relevance of the surfactant on stabilizing the SLNs interface, owing to the changes on the interfacial tension that it promotes. MA SLNs have proved to be highly stable over time and in a wide range of pH and salinity conditions, as well as having a high curcumin encapsulation efficiency. The MA SLNs prepared in this work provide a starting point to develop functionalized active nanocarriers which allow establishing a synergistic relation with the loaded drug. Full article

Two-dimensional materials allow for extreme light confinement, thus becoming important candidates for all optical application platforms. Monolayers of transition metal dichalcogenides are direct band gap semiconducting 2D materials featuring bandgaps in the visible and near-IR range, strong excitonic resonances, and high oscillator strengths, among other properties, as well as supporting exciton polaritons. The optical properties of quantum emitters, such as molecules or quantum dots, near single or multilayer transition metal dichalcogenides have been investigated, where the relaxation rate of the quantum emitter increases or decreases. The studies on the coupled quantum emitter—transition metal dichalcogenides remain so far in the weak light–matter coupling regime. In this work, we study the spontaneous emission spectrum of a two-level quantum emitter near a WS₂ layer, in which case the Purcell factor of the QE can take values up to 10⁴. We further study the Rabi splitting in the spontaneous emission spectrum at room temperature for a quantum emitter with free-space decay times in the 10 ps to 500 ps range. We observe that at close distance of the quantum emitter to the WS₂ layer, combined with short decay times, the spectrum can feature several peaks. In such cases, the Rabi splitting lies between 0.25 eV and 0.05 eV for increasing free-space decay times, indicating strong coupling conditions for the light–matter interaction between the quantum emitter and the WS₂ layer. Moreover, no simple relation between the inverse free-space decay time and the corresponding Rabi splitting value has been found. As the distance between the quantum emitter and the layer increases farther, the light–matter interaction coupling enters the weak coupling regime, which leads to vanishing Rabi splitting in the spontaneous emission spectrum for free-space decay times larger than a few tenths of ps. Full article

Cardiovascular disease (CVD) is a general term that includes diseases that affect the circulatory system and/or the heart. Their underlying pathology is atherosclerosis, an inflammatory disease characterized by the accumulation of lipids, inflammatory cells and fibrous tissue in the arteries' internal wall, provoking to some extent their obstruction. Atherosclerosis is still addressed as a simple disease instead of the complex interplay of different types of cells and cascade signaling pathways, so the use of any single imaging or therapeutic agent alone is unlikely to provide a satisfactory outcome. Hence, other treatment strategies need to be implemented, in particular, those using new nanomaterials able to target the plaque and to efficiently treat it, and that can be easily released by the body without provoking adverse effects. With this background, we have designed a biocompatible drug delivery vehicle that efficiently loads and protects the drug Atorvastatin (ATO reduces the LDL levels) while a folate receptor in the external shell targets inflamed areas. To avoid the common toxic effects of folic acid (FA) or ATO in the body at certain concentrations, the vehicle will provide covalent attachment for the FA on the surface and cage structure for ATO protection. To complement the treatment, genetic material will be included in a separate compartment to actively influence the regulation of immune responses and inflammatory disorders. Full article

Organic–inorganic hybrid perovskite solar cells have resulted in tremendous interest in developing future generation solar cells, due to their high efficiency exceeding 25%. For inverted type perovskite solar cells, the hole transporting layer plays a crucial role in improving the efficiency and stability of the perovskite solar cells by modifying band alignment, electric conductivity, and interfacial recombination losses. Here, vanadium doped NiO is selected as a hole transporting layer to study the impact of V dopant on the optoelectronic properties of NiO and photovoltaic performance. The prepared materials are characterized using XRD, SEM, TEM, and XPS. A TEM micrograph confirms that p-type materials have a small spherical dot structure. The V-doped NiO, used as a hole-extraction layer, can be prepared by a simple solvothermal decomposition method. The presence of V in the NiO layer has an influence on the conductivity of the NiO layer. Besides, synthesized p-type material can be used to fabricate a relatively low processing temperature, and has the advantage of a wide choice of transparent conductive oxide substrate. As a result, an inverted type planar perovskite solar cell incorporating of vanadium in NiO hole-transport layer improves the power conversion efficiency. The photovoltaic property of the prepared solar cell is measured under AM 1.5 G simulated light. The photocurrent density is 21.09 mA/cm², open-circuit voltage is 1.04 V, and the fill factor is 0.63. As a result, the overall power conversion efficiency reaches 13.82%. Full article

Carbogenic nanoparticles (also known as C-dots) constitute a new class of carbon-based materials, which are easily synthesized via thermal treatments of carbon-rich precursors. These spherical nano-emitters are composed of an amorphous core with an approximate size of below 10 nm and exhibit exquisite biocompatibility, simplicity of surface modification, excellent chemical stability and broad excitation spectra. Their exceptional photoluminescent properties are related to the dual emissive mode with the excitation-wavelength independent or dependent emission, attributed to the presence of organic fluorophores or carbogenic cores, respectively. To date, several nanomaterials have been developed to measure the intercellular pH, including fluorescent proteins, organic dyes and quantum dots. Among them, C-dots are characterized by resistance to photobleaching, good permeability and lack of toxic metal components in their structure. Moreover, these nanoemitters demonstrate excellent analytical performance in detecting heavy metals, drugs, biological molecules, poisonous reactants or explosives and thus can be applied as highly selective optical nanoprobes. In summary, our results demonstrate the potential to utilize biocompatible carbogenic nanotracers for an early-stage disease diagnosis as well as highlight their remarkable antimicrobial activity against Escherichia coli and Staphylococcus aureus. Full article

Triple negative breast cancer has a phenotype characterized by the absence of progesterone and estrogen receptors and the lack of HER2 overexpression. In order to find new strategies for treatment, single-walled carbon nanotubes (SWCNT) in combination with chemotherapeutics were studied and tested as new therapeutic tools. The objective of this study was to evaluate the efficiency of SWCNT in the transport of cisplatin (CDDP) for improving its cytotoxic effects on MDA-MB-231 cells. The nanoconjugates SWCNT-COOH-CDDP were obtained by the functionalization of SWCNT with carboxyl groups (SWCNT-COOH) and conjugation with CDDP. MDA-MB-231 cells were exposed to different doses of SWCNT-COOH, SWCNT-COOH-CDDP (0.01–2 µg/mL), and CDDP (0.00632–1.26 µg/mL) for 24 and 48 h. Cellular viability was monitored through an MTT test. The level of reactive oxygen species (ROS) and reduced glutathione (GSH) were evaluated using fluorescence and spectrophotometric methods, respectively. The expressions of Nrf2, caspase-3, caspase-8, and Bid proteins were assessed by immunoblotting in the presence of 0.5 and 1 µg/mL nanoconjugates. Additionally, the effects of SWCNT-COOH-CDDP on cell migration were monitored using a wound healing assay. The cellular viability decreased and ROS level increased in a time and dose-dependent manner in the presence of nanoconjugates relative to the control. Moreover, the level of GSH rose after 24 and 48 h of exposure to 0.5 µg/mL SWCNT-COOH-CDDP, while a decrease to 78.31% was recorded after 48 h in the presence of 1 µg/mL nanoconjugates. The expression of Nrf2 decreased to 33% after 24 h of treatment with 1 µg/mL SWCNT-COOH-CDDP and increased to 80% compared to the control (100%) after 48 h. Upregulation of caspase-3 and caspase-8 and downregulation of Bid post-exposure to 1 µg/mL SWCNT-COOH-CDDP was noticed. The inhibition of cell migration was observed after 24 and 48 h of exposure to 1 µg/mL SWCNT-COOH-CDDP. In conclusion, these nanoconjugates induced apoptosis in MDA-MB-231 cells, probably by both intrinsic and extrinsic pathways, by triggering the oxidative stress mechanisms, and inhibited their migration potential. Full article

The self-assembly of nanometric structures from molecular building blocks is an effective way to make new functional materials for biological and technological applications. In this work, we syn-thesized new dimeric bolaamphiphilic dehydrodipeptides, containing phenylalanine connected to a dehydroamino acid residue at the C-terminus. The N-terminus of the dipeptide was connected to both ends of a bifunctional central aromatic moiety, namely 1,4-benzenedicarboxylic acid and 1,3-benzenedicarboxylic acid. The potential use of these new compounds as hydrogelators was evaluated. The results showed that these synthesised compounds behave as efficient molecular hydrogelators, forming hydrogels with minimum gelation concentrations of 0.3–0.8 wt%. The self-assembly of these hydrogelators was investigated by the STEM microscopy technique, revealing different shapes depending on the N-aromatic moiety. STEM microscopy revealed that the hydro-gels are composed by fibers, ribbons and even spheres. Circular dichroism spectroscopy was also performed in order to evaluate the aggregation of the peptides into characteristic secondary struc-tures. Full article

The modification of the optical properties of semiconductor quantum dots near plasmonic nanostructures has attracted significant attention in recent years due to the several potential applications of the coupled nanostructures in optoelectronics, biophotonics and quantum technologies, including sensors, light harvesting, quantum information processing and quantum communication, imaging, photocatalysis, solar cells and others. One of the methods for modifying the nonlinear optical susceptibilities in quantum dots near plasmonic nanostructures uses the change of the spontaneous decay rates of quantum emitters due to the Purcell effect in a tailored nanophotonic environment. In this work, using this idea, we study the modification of the third-order nonlinear optical susceptibilities and specifically the phenomena of degenerate four-wave mixing and third-harmonic generation in a quantum dot that is coupled to a spherical metallic nanoparticle. We find that the strong alteration of the quantum dot’s spontaneous decay rate near the metallic nanoparticle gives strong variation, either enhancement or suppression, of the phenomena of degenerate four-wave mixing and third-harmonic generation for different distances of the quantum dot from the surface of the metallic nanoparticle, depending on the electric dipole direction of the quantum dot. We also show that the degree of enhancement or suppression of the nonlinear optical susceptibilities differs for the studied phenomena and it is stronger for degenerate four-wave mixing than for third-harmonic generation. This work may have important potential applications in the creation of nanoscale photonic devices for various technological applications. Full article

ZnO is an attractive semiconductor material due to its potential application in various fields such as solar cells, antibiotics, gas sensors, organic pollutant degradation, etc. For this purpose, researchers are trying to synthesize ZnO by using different methods such as sol–gel techniques, electrodeposition, mechanochemical and sonochemical methods, and chemical vapor deposition. However, it is still necessary to improve an economical method for synthesizing ZnO. In the present study, we synthesized ZnO nanoparticles (ZnO-NPs) by a thermal method. The process is environmentally safer than other methods because it does not involve more chemicals or a catalyst, acid, or base source. We used methylene blue for photocatalytic activity tests and Escherichia coli for antibacterial activity tests. The results found an outstanding degradation percentage (~99%) for the photocatalytic experiment. Moreover, the antibacterial activity was tested at different concentrations, and the minimum inhibitory concentration (MIC) of the ZnO-NPs was 30~50 μg/mL. Our synthesized ZnO-NPs were found to be more effective than previously described ZnO-NPs prepared via other methods. Full article

The beginnings of metal-organic frameworks (MOF) chemistry were established by Yaghi et al., in the 1990s. They started a new promising field for which, depending on the nature of the organic functionality and metal−ligand coordination chemistry, diversity of MOFs in terms of their structures and chemical properties is virtually endless. Since the 1990s it has been reported different synthetic routes (e.g., hydro-solvothermal synthesis, microwave and ultrasound-assisted synthesis, mechanochemistry, microemulsion synthesis, and continuous flow production). Nevertheless, no control on the shape and size of the crystal was achieved in a proper way. The results obtained during this work demonstrates that the surfactant plays an important role in the MOF´s synthesis protocol, in particular, in those with zeolitic imidazolate framework (ZIF-8) structure, by changing the former physico-chemical properties without altering their crystalline structure. That is, variations on surfactant´s properties lead to changes both in shape and size of MOFs without altering their intrinsic properties. Thus, this work is focused on the effect of two surfactants: sodium dodecyl sulfate (SDS) and hexadecyltrimethylammonium bromide (CTAB). In this sense, for each family of surfactant the influence of the surfactant tail chain length and the nature of their head group were investigated. For these studies, dynamic laser-light scattering (DLS), scanning electron microscopy (SEM) and powder X-ray diffraction (PXRD) were performed in order to characterize the physicochemical properties and the morphology of the obtained MOFs. Full article

Nanomedicines’ inability to penetrate throughout the entire volume of a tumor due to heterogeneous distribution within the tumor mass remains a crucial limiting factor for a vast range of theranostic applications, including image-guided radiation therapy. Despite many studies conducted on the topic having shown the efficacy and biocompatibility of colloidal gold nanoparticles (GNPs), the biological effects of GNPs in the tumor microenvironment, including the particle–protein interaction and the consequent impact on cellular pathways and contrast enhancement remain unclear. In this regard, further investigations on how GNP surface passivation affects X-ray attenuation as well as in vivo biodistribution will clarify several aspects still under discussion in the scientific community, which so far have limited the clinical translation of their cancer-related applications. We aim to evaluate the influence of protein surface adsorption on the GNP biodistribution in Lewis lung carcinoma (LLC) tumor-bearing mice using high-resolution computed tomography (CT) pre-clinical imaging. We hypothesize that, by controlling the adsorption of proteins on the GNP surface, we can influence the intratumoral distribution and retention of the particles. GNPs approximately 34 nm in diameter were synthesized with a surface plasmon peak at ~530 nm, surface passivated with bovine serum albumin (BSA) to reduce opsonization and improve colloidal stability, and characterized with standard methods. Modulation of BSA adsorption on the GNPs was observed by tuning the pH of the immobilization medium from acidic to alkaline, which we quantified using Langmuir isotherms. CT phantom imaging was used to determine X-ray attenuation as a function of GNP concentration and surface functionalization. The in vitro study for evaluating the uptake of GNPs by LLC cells highlighted a difference in the internalization depending on the surface functionalization. In both cases, macropinocytosis was the trafficking mechanism, but while endosomes with citrate-GNPs can be found in different stages of maturation, cells treated with BSA-GNPs presented larger vesicles up to 1 μm in diameter. The in vivo study was performed by injecting intratumorally, concentrating GNPs into LLC solid tumors grown on the right flank of 6-week-old female C57BL/6 mice. Ten days post-injection, follow-up assessments with CT imaging showed the distribution and retention of the particles in the tumor. CT attenuation quantification based on bioimaging analysis for each time point was conducted. In vivo results showed significant heterogeneity in the intratumoral biodistribution of GNPs dependent on surface passivation. BSA-GNPs perfused predominately along the tumor periphery with few depositions throughout the entire tumor volume. This response can be explained by the abnormal and heterogeneous vascular structure of the LLC tumor, suggesting perfusion rather than permeability as the limiting factor for tumor accumulation of the GNPs. Despite the perivascular cluster accumulation, the BSA-GNP distribution diverged from that obtained after unpassivated, citrate-GNP intratumoral injections. In conclusion, our investigations have shown that surface passivation of GNPs is able to influence the mechanism of cellular uptake in vitro and their in vivo intratumoral diffusion, highlighting the spatial heterogeneity of the solid tumor. Full article

Alterations in neurogenesis result in the inevitable loss of brain nervous tissue and cause neurodegenerative diseases, such as Parkinson’s disease (PD), Alzheimer’s disease (AD), and Huntington’s disease (HD). In this regard, hydrogels based on natural biopolymers have attractive properties, such as excellent biocompatibility, a low immune response, and a significant similarity to the extracellular matrix (ECM) of tissues, thus supporting cell proliferation and migration. Human ECM is composed by relatively small amounts of fibrous, proteins, and polysaccharides. For example, scaffolds composed of gelatin and hyaluronic acid are highly abundant components in human ECM. The methacrylation of hyaluronic acid (HAMA) and gelatin (GelMA) through carboxyl and hydroxyl groups under UV light radiation at 365 nm produce polymeric scaffolds with elastic moduli similar to tissues, and, therefore, potential candidates to adhere, host, and facilitate cell proliferation and differentiation, which are dependent on their mechanical properties. In this work, the mechanical, thermal, and morphological properties of HAMA and GelMA hydrogel mixtures were studied and characterized via linear rheological measurements, thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). Full article

Gene delivery is a promising therapeutic approach for a variety of diseases. However, the exact physical mechanisms of transfection agent-mediated gene delivery are yet to be fully understood. The endosomal membrane is a major barrier for efficient transfection, and endosome escape has become known as a crucial step in the delivery of nucleic acids. Previous research revealed distinct reagent-mediated membrane disruption mechanisms: the formation of small pores allowing protons to pass biological membranes and the permeabilization of large molecules such as LDH through amphiphilic translocation. Here, we measure the membrane permeation of protons in cultured cells after exposition to commercial transfection agents at endosomal pH conditions (pH 5.5) using a proton-sensing transistor (ISFET). In addition, we characterize the effect of transfection agents on cytosolic LDH leakage from cultured cells. Comparing the results from both assays at endosomal pH indicates that both types of transfection reagents have pore-forming activity at endosomal pH, while there is no such activity at pH 7.4. The pores formed by polymer-based reagents result in LDH leakage, whereas lipid-based reagents do not. This suggests a mechanistical difference in terms of the size of the pores formed. The effect of this difference on the endosomal escape profile is also investigated with a CLSM-based assay. These data indicate that the ISFET may be used to more accurately assess the endosome escape capabilities of different gene carriers. Full article

Obesity and glioblastoma multiforme (GB) are two unmet medical needs where effective therapies are lacking. Carnitine palmitoyl transferase 1 (CPT1), an enzyme catalyzing the rate-limiting step in fatty acid oxidation (FAO), is a viable target for both diseases. C75, a fatty acid synthase (FAS) inhibitor, forms an adduct with coenzyme A (CoA) to form C75-CoA, which is a strong competitive inhibitor to CPT1 that is selective in its target. However, it is polar and charged, having low cell membrane permeability, and therefore needing a delivery system for intracellular transport. (±)-C75-CoA and its enantio-separated forms (+)- and (−)-C75-CoA were used to form poly-ion complex (PIC) micelles with the cationic block co-polymer PEG-PAsp(DET). The drug and polymer were mixed in a 1:1 anion/cation ratio to give 50–70 nm micelles with a unimodal size profile and narrow polydispersity. Size was maintained upon introduction of physiological saline. Micellar (±)-, (+)-, and (−)-C75-CoA were all significantly more cytotoxic compared to the respective free drugs in U87MG. We examined whether C75-CoA inhibits FAO by measuring ATP concentrations in U87MG and GT1-7. ATP generation was found to be hampered after adding C75-CoA in both cell types, with micelle-treated cells producing significantly lower ATP than those treated with free drug, suggesting that the effective intracellular delivery of C75-CoA leads to a more pronounced FAO inhibition. A fluorescent CoA derivative, Fluor-CoA, also yielded monodisperse micelles similar to C75-CoA. Micellar internalization was significantly greater than that of the free dye. Uptake of both increased with time, with this effect is more pronounced in U87MG than GT1-7. The %Fluor-CoA+ cells were also expressively higher for the micelle across cell lines. From this data, it can be convincingly concluded that neuronal and glioma cellular uptake of micelles is superior to that of the free dye, validating the need for cellular delivery systems for anionic, CoA-type molecules. The micellar form neutralized the negative charge of the cargo, promoting transport into the cell. These outcomes strongly support the effectiveness of using a PIC micelle-type system to deliver anionic small molecules into glioma cells and neurons meant to inhibit enzymes such as CPT1, for future applications in diseases like obesity and cancer. Full article

Combining soft and hard magnetic materials is not only of technological importance in diverse spintronics elements, but also of high interest in basic research. Here, we report on different arrays combining iron and nickel, e.g., by embedding circular nanodots of one material in a matrix of the other. Micromagnetic simulations were performed using OOMMF. Our results show that magnetization reversal processes are strongly influenced by neighboring nanodots and the magnetic matrix in which the nanodots are embedded, respectively, which becomes macroscopically visible by several steps along the slopes of the hysteresis loops. Such material combinations allow for preparing quaternary memories and are thus highly relevant for applications in data storage and processing. Full article

Structural evolutions in liquid tellurium (Te) are observed by employing molecular dynamics simulations at various temperatures ranging from 1500 K to 300 K. Local structural variations are noticed in radial correlation functions, structure factors, bond angle distribution functions, Honeycutt–Anderson index, Voronoi tessellation, and coordination numbers. Upon quenching, we found that icosahedral short-range motifs dominated in a stable and supercooled liquid state. The first peak of the radial distribution function at 970 K and 722 K is in excellent agreement with the findings of neutron diffraction. The transformation to a supercooled liquid state with distorted icosahedral patterns is observed at 600 K and to a body-centered cubic cluster after 600 K. Finally, we also show that near the melting point diffusion coefficient of liquid tellurium is fairly consistent with the tight-binding and experimental models. We assume that our findings not only replicate all the remarkable characteristics but also predict useful transition mechanisms through the use of the well-known Stillinger–Weber potential. Full article

In recent decades, unprecedented progress has been made in the field of oncology. Yet, cancer continues to affect millions of people globally despite major breakthroughs. The advances in cancer therapy for all types of cancers have not been uniform, and certain types of cancer remain intractable. There is no doubt a need for innovative and multidimensional efforts to solve this persistent problem. In our laboratory, we use polymeric micelle-based nanomedicines [1] that offer a unique ability for realizing coordinated functionality, such as active targeting [2] and spa-tiotemporally controlled drug action [3], which can efficiently transport and selectively activate the drug in the tumor microenvironment (TME). With useful biocompatible and biodegradable features, block copolymer micelles offer significant clinical translation potential [1]. As a step forward, we have developed next-generation nanomedicines that can better synchronize with in-trinsic TME features, such as dysregulated pH or metabolic alteration. Furthermore, the use of a clinically relevant nanomedicine, incorporating an ICD-inducing drug, has been expanded by reversing cold GBM into hot tumors to synergize the efficacy of anti-PD1 therapy [4]. Full article

In the field of Transition Metal Dichalcogenides (TMDCs), molybdenum disulfide (MoS₂) has attracted an outstanding interest due to it having several applications. MoS₂ has potentialities not yet fully realized in solution-based applications. However, the lack of knowledge of the optical properties of MoS₂, especially in the infrared range, has significantly limited its use in many exciting photonic fields. In this work, the broadband optical properties of MoS₂ films deposited by spin-coating onto Si/SiO₂ substrates were studied by means of Variable Angle Spectroscopic Ellipsometry (VASE). The morphological and the structural properties of the samples were investigated by Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM) and Micro-Raman Spectroscopy. Micro-Raman spectroscopy measurements reveal the presence of 2H-MoS₂ and 1T-MoS₂ phases. The optical properties of the films show a mid-gap state at 0.6 eV, not reported in an ellipsometry work before, induced by defects in the MoS₂ samples. Full article

The manipulation of exciton and biexciton transitions in semiconductor quantum dots using laser pulses is an active research area, embodying various theoretical and experimental investigations. Within this context, a problem which has attracted significant attention is the coherent preparation of the biexciton state, when the quantum dot is initially in its ground state. A basic approach employs a linearly-polarized single laser pulse that drives the exciton-biexciton cascade with a two-photon transition between ground and biexciton states. The two frequently used laser pulse shapes are the constant and hyperbolic secant profiles. In this work, we show that a simple on-off-on pulse-sequence, with pulse durations obtained from the solution of a transcendental equation, can achieve complete preparation of the biexciton state faster than the commonly used constant and hyperbolic secant pulses. Moreover, using numerical optimal control, we demonstrate that for a wide range of values of the maximum pulse amplitude, the proposed pulse-sequence prepares the biexciton state in the minimum possible time, thus provides the quantum speed limit of the system (for fixed maximum control amplitude). We finally show with numerical simulations that, even in the presence of realistic dissipation and dephasing, high levels of biexciton state fidelity can be generated in short times. Full article

A promising method for the synthesis of ultrafine carbide particles is the sol–gel method using dispersions of molybdenum–tungsten nanoparticles. For further use, the main properties of molybdenum-blue nanoparticles, including the size, structure, and stability, under different conditions must be determined. The synthesis of dispersions of molybdenum–tungsten blue was carried out as a result of the reduction of molybdate and tungstate ions in the presence of hydrochloric acid. Ascorbic acid was chosen as a reducing agent and further acted as a carbon source. Dispersions and nanoparticles were investigated by transmission electronic microscopy (TEM), UV/vis and infrared (FTIR) spectroscopy, and dynamic light scattering (DLS). Full article

Molybdenum blue dispersions were synthesized by reducing an acidic molybdate solution with glucose, hydroquinone and ascorbic acid. The role of the H/Mo molar ratio in the process of formation for molybdenum particles was established. For each reducing agent, the conditions for the formation of aggregative stable dispersion of nanoclusters with the maximum concentration of particles were determined. The dispersed phase was represented by toroidal molybdenum oxide nanoclusters, which was confirmed by the results of UV–Vis, FTIR, XPS spectroscopy, DLS and TEM. Full article

Among emerging Transition Metal Dichalcogenides (TMDCs), molybdenum disulfide (MoS₂) has attracted a remarkable interest due to its many possible applications. In particular, MoS₂ has potentialities not yet fully realized in solution-based applications. The morphological and the structural properties of MoS₂ films deposited by spin-coating onto Si/SiO₂ substrates were investigated by Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM) and Micro-Raman Spectroscopy. High resolution AFM imaging highlights the presence of a layered structure. The thickness of each layer is estimated to be around 13 nm. Micro-Raman measurements reveal that there is a coexistence between 2H-MoS₂ and 1T-MoS₂ phases, which could be useful for electrical applications. Moreover, the band at 290 cm⁻¹ is assigned to the amorphous phase of MoS₂. The detectability of the mode E_1g in back scattering geometry is ascribed to the disorder of the amorphous phase. Full article

Nanosized coatings of ZrO₂ were deposited on silicon substrates using sol-gel and spin coating techniques. The precursor solutions were prepared from ZrOCl₂.8H₂O with the addition of different percentage (0.5–5%) of rare earth Gd³⁺ ions as dopant. The thin films were homogeneous, with average thickness of 115 nm and refractive index (n) of 1.83. The X-ray diffraction analysis (XRD) revealed the presence of a varying mixture of monoclinic and tetragonal ZrO₂ polycrystalline phases, depending on the dopant, all of which with nanosized crystallites. Scanning electron microscopy (SEM) as well as atomic force microscopy (AFM) methods were deployed to investigate the surface morphology and roughness of the thin films, respectively. They revealed a smooth, well uniform and crack-free surface with average roughness of 0.8 nm. It was established that the dopant concentration affects the photoluminescence (PL) properties of the samples. The undoped films exhibited broad violet-blue PL emission, while the addition of Gd³⁺ ions resulted in new narrow bands in both UV-B and visible light regions, characteristic of the rare earth metal. The intensive emission located at 313 nm can find useful application in medical lamps for treatment of different skin conditions. Full article

mRNA is a promising therapeutic nucleic acid, although effective delivery systems are required for its broad application. Polyion complex (PIC) micelles loading mRNA via polyion complexation with block catiomers are emerging as promising carriers for mRNA delivery, but the PIC stability has been limited so far. Controlling the binding of polycations to mRNA could affect the micelle stability. Nevertheless, the impact of binding affinity between polycations and mRNA on the function of mRNA-loaded PIC micelles (mRNA/m) remains unknown. Herein, we review our recent orthogonal approaches controlling the stiffness and the valency of polycations to improve the performance of mRNA/m toward enhancing stability and delivery efficiency. Thus, block catiomers with contrasting flexibility were developed to prepare mRNA/m. The flexible catiomer stabilized mRNA/m against enzymatic attack and polyanion exchange compared to the rigid catiomer, promoting protein translation in vitro and in vivo, and prolonged mRNA bioavailability in blood after systemic injection. Based on these observations, we also developed flexible catiomers with different valencies. The guanidinated catiomer stabilized mRNA/m compared to the aminated catiomers, facilitating intracellular delivery and eventual gene expression. Our findings indicate the importance of controlling the polymer binding to mRNA for developing flexible polycation-based systems directed to in vivo applications. Full article

In this work, we present numerical results on the influence of a spherical metallic nanoparticle to the population transfer in a $\Lambda$-type quantum system under conditions of Stimulated Raman Adiabatic Passage (STIRAP). For the study of the system’s dynamics, we use the density matrix approach for the quantum system, where the parameters for the electric field amplitudes and the spontaneous decay rates have been calculated using ab initio electromagnetic calculations for the plasmonic nanoparticle. We present results for the evolution of the populations of the different levels of the quantum system as a function of different parameters, in the presence and the absence of the plasmonic nanoparticle. We find that the presence of the plasmonic nanoparticle and the polarization of the pump and Stokes fields with respect to the surface of the nanoparticle, affect the efficiency of the population transfer inside the three-level quantum system. For the right combination of the values of the modified spontaneous decay rates and the fields intensities, high efficiency population transfer is obtained in the quantum system near a plasmonic nanoparticle using STIRAP process. Full article

We theoretically study the nonlinear optical rectification of a Zinc-phthalocyanine molecular complex, modelled as a polar two-level quantum system, interacting with an optical field near a gold nanoparticle. We use the steady-state solution of the density matrix equations for determining the nonlinear optical rectification coefficient in this case. We further use first-principle electronic structure calculations for determining the energies of the molecular states involved and the corresponding transition and permanent electric dipole moments, as well as first-principle classical electromagnetic calculations for calculating the influence of the metallic nanoparticle on the decay rates of the molecular states due to the Purcell effect and on the external electric fields applied on the molecule. We investigate the nonlinear optical rectification coefficient in the absence and the presence of the plasmonic nanoparticle for various parameters, such as the field polarization and the distance between the molecular complex and the plasmonic nanoparticle. We find that the nonlinear coefficient can be significantly enhanced for specific field polarization and at suitable distance between the molecule and the plasmonic nanoparticle. We also find that this process is highly efficient at weak field intensity, zero pure dephasing rate and for small values of the transition dipole moment. Full article

Due to their intrinsic viscosity and hydrophilicity, nanohydrogel systems are used to significantly increase the efficiency of commercial contrast agents for MRI and thus effectively improve the sensitivity of the MRI technique. Since chitosan (CS) is a biocompatible polysaccharide frequently used in biomedical applications, we aimed to prepare chitosan nanohydrogels (NGs) by ionic gelation, the polysaccharide being further grafted with rhodamine (RBITC) and fluorescein isothiocyanate (FITC). In this way, the cytotoxic effect of different concentrations (5, 15, 30, 60, and 120 µg/mL) of the fluorescent CS-FITC and CS-RBITC NGs was investigated by assessing the plasma membrane integrity and the metabolic activity of RAW 264.7 murine macrophages and A20 mouse lymphoma B cells following exposure for 6 and 24 h. The cell viability (MTT assay) and lactate dehydrogenase activity were analyzed by spectrophotometric methods, while cellular uptake was observed by fluorescence microscopy. Our results showed that the exposure to CS-FITC and CS-RBITC NGs for 6 and 24 h did not induce significant changes to RAW 264.7 and A20 cells compared to control, proving a good nanogel biocompatibility for both cell lines. In addition, the fluorescence microscopy showed that cellular uptake was quite rapid and efficient for the NGs tested. Taking all of these into consideration, we can conclude that all types of nanohydrogels were biocompatible, being internalized in both cell types with predominantly cytoplasmic localization. Full article

Conducting films comprising conducting polymers and carbon nanomaterials have gained a lot of interest for applications in several fields, including transparent electrodes, supercapacitors, light-emitting diodes (LEDs), polymer solar cells (PSCs), etc. One of the main motivations is the replacement of costly oxides and degradable materials, like indium tin oxide (ITO). On the other hand, graphene oxide (GO) has emerged as an ideal filler to reinforce polymeric matrices owing to its large specific surface area, transparency, flexibility, and very high mechanical strength. Nonetheless, functionalization is required to improve its solubility in common solvents and expand its practical uses. In this work, the potential of polymer nanocomposites based on hexamethylene diisocyanate (HDI)-functionalized GO (HDI-GO)/poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)(PEDOT:PSS) for use as active layers (ALs) or interfacial layers (IFLs) in PSCs has been assessed. Conventional deposition techniques applied to thin films were tested for the developed nanocomposites. Deposition methods included drop and spin casting, where different type of substrates, as clean glass and glass/ITO were tested. The results of deposition essays were analyzed by atomic force microscopy (AFM) and UV-Vis spectroscopy. In addition, thermal evaporation was tried with the aim of obtaining homogeneous layers. The layers obtained by drop casting showed poor film quality, with large aggregates. On the other hand, spin coating lead to layers not fully wetting the substrate. New synthesis procedures for the nanocomposites and/or alternative treatments of the substrate surface will be investigated in the future to optimize their composition and properties (i.e., transparency) and improve their suitability for use in PSCs. Full article

Nanogels are a novel class of three-dimensional cross-linked polymers able to retain high amounts of water in their network structure, with large potential applications in nanomedicine. In our study, the polymer matrix selected was chitosan, as this polysaccharide biopolymer composed of N-acetylglucosamine and glucosamine residues exhibits great biocompatibility and low toxicity. The preparation was performed by ionic gelation in the presence of hyaluronic acid and sodium tripolyphosphate, with rhodamine or fluorescein isothiocyanate molecules grafted on a chitosan backbone. In order to validate the possible usage of these chitosan-fluorophores conjugates for fluorescence imaging purposes in cancer diagnostics and therapy, their biological effect was assessed on SVEC4-10 cells (a simian virus 40-transformed mouse microvascular endothelial cell line). Cell viability, membrane integrity and nanogels uptake were examined following exposure for 6 and 24 h at concentrations up to 120 µg/mL. A good biocompatibility was obtained after both time intervals of incubation with nanogels, with no increase in cell death or membrane damage being noticed as compared to control. By examination on confocal laser scanning microscopy, both types of fluorescent nanogels agglomerated on the surface of the cell membrane, their cellular internalization being observed only for few cells, preferentially at the cell periphery. In conclusion, based on the biocompatibility of the nanogels, these can further incorporate gadolinium for an improved magnetic resonance imaging effect in nanomedicine. Full article

Horizontally shifted and asymmetric hysteresis loops are often associated with exchange-biased samples, consisting of a ferromagnet exchange-coupled with an antiferromagnet. In purely ferromagnetic samples, such effects can occur due to undetected minor loops or thermal effects. Simulations of ferromagnetic nanostructures at zero temperature with sufficiently large saturation fields should not lead to such asymmetries. Here we report on micromagnetic simulations at zero temperature, performed on sputtered nanoparticles with different shapes. The small deviations of the systems due to random anisotropy orientations in the different grains can not only result in strong deviations of magnetization reversal processes and hysteresis loops, but also to distinctly asymmetric, horizontally shifted hysteresis loops in purely ferromagnetic nanoparticles. Full article

Chemical vapor deposition synthesis of graphene on copper foil from methane is the most promising technology for industrial production. However, an important problem of the formation of the second and subsequent graphene layers during synthesis arises due to the strong roughness of the initial copper foil. Here we demonstrate the various approaches to prepare a smooth copper surface before graphene synthesis to reduce the formation of multi-layer graphene islands. Six methods of surface processing of copper foils are studied, and the decrease of the roughness from 250 to as low as 80 nm is achieved. The correlation between roughness and the formation of multi-layer graphene is demonstrated. Under optimized conditions of surface treatment, the content of the multi-layer graphene islands drops from 9% to 2.1%. The quality and the number of layers of synthesized graphene are analyzed by Raman spectroscopy, scanning electron microscopy, and measurements of charge mobility. Full article

Several biological barriers are generally responsible for the limited delivery of cargoes at the cellular level. Fullerenols have unique structural features and possess suitable properties for interaction with the cells. This study aimed to synthesize and characterize a fullerenol derivative with desirable characteristics (size, charge, functionality) to develop cell penetration vehicles. Fullerenol was synthesized from fullerene (C₆₀) solubilized in toluene, followed by hydroxylation with hydrogen peroxide and tetra-n-butylammonium hydroxide (TBAH) as a phase transfer catalyst. The obtained product was purified by a Florisil chromatography column (water as the eluent), followed by dialysis (cellulose membrane dialysis tubing) and freeze-drying (yield 66%). Subsequently, a silane coupling agent was conjugated on the fullerenol surface to render free amine functional groups for further covalent functionalization with other molecules. Characterization via UV–VIS, FTIR-ATR, Raman, DLS, and SEM techniques was conducted to evaluate the composition, size, morphology, surface functionality, and structural properties. We are currently working on the conjugation of the potent cell-penetrating agents Buforin II (BUFII) and the Outer Membrane Protein A (OmpA) on the surface of the fullerenol to estimate whether cell penetration and endosome escape are improved concerning conventional polymeric vehicles and our previous developments with iron oxide nanoparticles. Full article

We present a simple and fast methodology to realize metal contacts on two-dimensional nanosheets. In particular, we perform a complete characterization of the transport properties of MoS₂ monolayer flakes on SiO₂/Si substrates by using nano-manipulated metallic tips as metallic electrodes directly approached on the flake surface. We report detailed experimental investigation of transport properties and contact resistance in back-gated field effect transistor in which the Si substrate is used as the gate electrode. Moreover, profiting of the n-type conduction, as well as the high aspect ratio at the edge of the MoS₂ flakes, we also explored the possibility of exploiting the material as a field emitter. Indeed, by retracting one of the metallic probes (the anode) from the sample surface, it has been possible to switch on a field-emitted current by applying a relatively low external electric field of few-tens of Volts for a cathode-anode separation distance below 1 µm. Experimental data are then analyzed in the framework of Fowler-Nordheim theory and its extension to the two-dimensional limit. Full article

We elaborate the synthesis and remarkable photocatalytic efficiency of a series of heterojunction nanocomposites with a cauliflower-like architecture composed of copper oxide (CuO) and single-walled carbon nanotubes (SWCNTs). The photocatalysts with such a peculiar design were constructed via facile recrystallization followed by calcination and were symbolized as CuO-SWCNT-1, CuO-SWCNT-2, and CuO-SWCNT-3, representing the components and calcination time in hours. The photocatalytic efficiency of the synthesized nanocomposite samples were investigated by evaluating the decomposition of methylene blue (MB) solution under natural sunlight exposure. All of the as-synthesized photocatalysts were substantially effectual for the photo-deterioration of MB solution. Moreover, CuO-SWCNT-3 revealed the top photocatalytic capability with 96% decomposition of MB solution in 2 h while being exposed to visible light. Pristine CuO nanocrystals and the SWCNTs were employed as controls, whereas the photocatalytic performance of the hetero-composites was significantly better than that of pure CuO as well as SWCNTs. The recyclability of the photocatalysts was also explored, and the results asserted that the samples could be reused for five cycles without being altered notably in photocatalytic performance or morphology. Full article

The voltage-gated proton channel (Hv1) plays the important role in proton extrusion, pH homeostasis, sperm motility, and cancer progression. The closed-state structure of Hv1 was recently revealed by X-ray crystallography. However, the opened-state structure has not been captured yet. To investigate the mechanism of proton transfer in Hv1, molecular dynamics (MD) simulations were performed with the closed-state structure of Hv1 under electric field and pH conditions. The residues arrangement on the closed-state structure revealed that the selectivity filter (Asp108) which is located in the hydrophobic layer (consists of two Phe residues 146 and 179) might prevent water penetration. In molecular dynamics simulations, we observed that the channel opened by moving 3 Arg up on the S4 helix and a continuous hydrogen-bonded chain of water molecules (a “water wire”) went through the channel when it opened. During simulations, the open channel allowed water molecules to pass through the channel but excluded other ions. This indicates the Hv1 channel is highly selective for protons. Our results clearly showed the Hv1 channel is voltage-and pH-gradient sensing. Full article

Polyaniline (PANI) is a cheap and widely used conducting polymer due to its exceptional electrical and optoelectronic properties. However, it is insoluble in conventional organic solvents and degrades at high temperatures. To improve the performance of PANI, carbon-based nanomaterials, such as graphene, graphene oxide (GO), and their derivatives, can be incorporated into a PANI matrix. In this work, hexamethylene diisocyanate-modified GO was used as a reinforcement to prepare PANI/HDI−GO nanocomposites by means of the in situ polymerization of aniline in the presence of HDI−GO followed by ultrasonication and solution casting. The effect of the HDI−GO functionalization degree and concentration on the final properties of the nanocomposites was explored by scanning electron microscopy (SEM), Raman spectroscopy, X-ray diffraction (XRD), thermogravimetric analysis (TGA), tensile tests, and four-point probe measurements. A homogenous dispersion of the HDI−GO nanosheets was found as well as very strong PANI-HDI−GO interactions via pi-pi stacking, H-bonding, and hydrophobic and electrostatic charge-transfer complexes. A continuous improvement in thermal stability and electrical conductivity was found with increasing nanomaterial concentration, the increments being larger with the increasing HDI−GO degree of functionalization. The nanocomposites showed a very good combination of rigidity, strength, ductility, and toughness. The approach developed herein opens up a versatile route to prepare multifunctional graphene-based nanocomposites with conductive polymers for a broad range of applications, including photovoltaic organic solar cells. Full article

Gene therapy has been considered a promising strategy for treating several inherited diseases and acquired complex disorders. One crucial challenge yet to be solved to ensure the nanomaterials’ success in delivering gene therapies is their ability to escape from endosomes. To address this issue, we previously developed magnetite nanoparticles conjugated with the antimicrobial peptide Buforin II, which showed potent translocating and endosomal escape abilities in several cell lines. In this work, we propose developing new cell-penetrating nanoplatforms by interfacing graphene oxide (GO) with powerful translocating peptides to take advantage of already tested and unique peptides as well as the distinctive interactions of GO with the phospholipids of membranes and endosomes. GO was prepared by the modified Hummers’ method through the oxidation of graphite sheets. Next, the functionalization of GO was carried out by rendering pendant amine groups to the GO surface. Thermogravimetric analysis (TGA) and Fourier-transform infrared spectroscopy (FTIR) were used to corroborate the successful functionalization of the nanoplatform. FTIR analysis exhibited the peaks related to the distinct carboxyl groups of GO and the Si–O bonds after silanization. TGA allowed us to estimate a silanization efficiency of 38%. Future work will be focused on conjugating Buforin II and assessing translocation efficiency by conducting uptake assays in liposomes and various cell lines. Additionally, endosomal escape will be determined via confocal microscopy by labeling the peptide with fluorescent molecules and examining colocalization with the fluorescent marker of endosomes, LysoTracker. By taking advantage of the exceptional qualities in terms of the physicochemical, electrical, and optical properties of GO, this study might provide novel strategies to overcome limitations commonly faced, such as low stability of the translocating biomolecules and endosomal entrapment. Full article

The nanosized clusters of molybdenum blues and their monodispersity make them possible to consider as promising precursors for molybdenum carbide preparation. For the synthesis of supported catalysts using sols (dispersions of nanoparticles), it is necessary to know their main colloidal-chemical properties (electro-surface characteristics, rheological properties and the conditions of aggregative stability). This paper presents the results of a study of the colloidal-chemical properties of molybdenum blue, the dispersed phase of which is represented by toroidal particles of the Mo154-x family. It was found that aggregate stable sols exist in the range of 0.8 ˂ pH ˂ 2.0. In this range, molybdenum blue particles are negatively charged, and the electrokinetic potential does not exceed 30 mV. Molybdenum blues have high aggregate stability and can be concentrated to a high concentration of the dispersed phase (20–30 wt%); at a concentration more than 30 wt.%, a transition of the sol into a gel is observed. In a wide range of concentrations, molybdenum blues are Newtonian liquids, and the viscosity mainly depends on the concentration of the dispersed phase. The results obtained can be used as a basis for the development of a sol–gel method of supported catalysts based on molybdenum blue. Full article

In this work, monolayer molybdenum disulfide (MoS₂) nanosheets, obtained via chemical vapor deposition onto SiO₂/Si substrates, are exploited to fabricate field-effect transistors with n-type conduction, high on/off ratio, steep subthreshold slope and good mobility. We study their electric characteristics from 10⁻⁶ Torr to atmospheric air pressure. We show that the threshold voltage of the transistor increases with the growing pressure. Moreover, Schottky metal contacts in monolayer molybdenum disulfide (MoS₂) field-effect transistors (FETs) are investigated under electron beam irradiation conditions. It is shown that the exposure of Ti/Au source/drain electrodes to an electron beam reduces the contact resistance and improves the transistor performance. It is shown that e-beam irradiation lowers the Schottky barrier at the contacts due to thermally induced atom diffusion and interfacial reactions. The study demonstrates that electron beam irradiation can be effectively used for contact improvement though local annealing. It is also demonstrated that the application of an external field by a metallic nanotip induces a field emission current, which can be modulated by the voltage applied to the Si substrate back-gate. Such a finding, that we attribute to gate-bias lowering of the MoS₂ electron affinity, enables a new field-effect transistor based on field emission. Full article

In this work, we report the fabrication of germanium arsenide () field-effect transistors with ultrathin channel and their electrical characterizations in a wide temperature range, from to . We show that at lower temperatures, the electrical conduction of the channel is dominated by the 3D variable range hopping but becomes band-type at higher temperatures, after the formation of a highly conducting two-dimensional (2D) channel. The presence of this 2D channel, limited to a few interfacial layers, is confirmed by the observation of an unexpected peak in the temperature dependence of the carrier density per area at . Such a feature is explained considering a model based on a temperature-dependent channel thickness, corroborated by numerical simulations, that show excellent agreement with the experimental data. Full article

Graphene quantum dots (GQDs) represent nanoscale structures with strong quantum and exceptional photoluminescence properties. These particles have promising applications in nanomedicine, specifically for diagnostics, cargo delivery, photothermal therapy and bioimaging. In this context, we aimed to characterize GQDs available on the market for further utilization for in vivo purposes. Transmission and scanning electron microscopy (TEM and SEM), and energy dispersive X-ray spectroscopy (EDX), were used to characterize the morphology and elemental composition of GQDs. In addition, the hydrodynamic size and the zeta potential were measured for these nanoparticles. Their biocompatibility was investigated on human fibroblast lung cells (MRC-5 cell line) after 24 and 72 h of incubation with concentrations up to 200 μg/mL of GQDs. TEM images showed graphene sheets with few wrinkle structures, the dots having uniform diameters in the range between 1.0 and 5.0 nm. SEM examination revealed the three-dimensional structure with a sponge-like aspect and pores of various sizes. Their tendency to aggregate provided the formation of aggregates with sizes of hundreds of nanometers, as revealed by the hydrodynamic diameter of about 270 nm. A negative zeta potential of −16 mV confirmed the anionic character of GQDs. Concentrations up to 50 μg/mL exhibited a low toxicity in lung cells, as revealed by MTT assay and fluorescent microscopy of actin cytoskeleton after both time intervals, confirming potential further testing on animals for clinical purposes. However, the high doses of GQDs induced cell death and must be avoided in future. Given the new experimental evidence obtained on GQDs, more knowledge has been achieved, which is very useful for prospective research to revolutionize the future of nanomedicine and biotechnology. Full article

We report the characterization of back-gated field-effect transistors fabricated using platinum diselenide (PtSe2) ultrathin films as a channel. We perform a detailed study of the electrical conduction as well as of the photoconductivity. From the gate modulation of the channel current, we obtain the signature of p-type semiconducting conduction with carrier mobility of about 30 cm² V⁻¹ s⁻¹. More interestingly, PtSe2 devices exposed to light, either in air and in vacuum, exhibit negative photoconductivity, which we explain by a photogating effect due to charge trapping in the gate dielectric and light-induced desorption of adsorbates. Full article

Dye removal from manufacturing and textile industry wastewater is one of the biggest challenges in plants. The improper disposal of water with residual dyes can contaminate effluents and fresh water sources. In this work, filtration membranes based on reduced graphene oxide (rGO) were fabricated by the spray coating method, and its capability to remove dyes from water was evaluated. Graphene oxide was prepared by a modified Hummers method and posteriorly reduced with ascorbic acid; a simple and fast spray coating fabrication method was employed to produce stable membranes, which were analyzed in a home-made permeation cell. Raman spectroscopy and scanning electron microscopy (SEM) were able to prove that rGO dispersion was formed by graphene flakes with about 45.9 μm of lateral dimension; X-ray diffraction, SEM and Raman analyses indicate that the spray method was efficient in producing stable and uniform filtration membranes; and UV-vis absorption spectra of feed and permeation solution indicate that rGO membranes were capable in removing dye from water. By the main results, it is possible to affirm that rGO filtration membranes are an efficient, low-cost, scalable and fast way to remove dyes from wastewater. Full article

Nowadays, nanoparticles (NPs) are used to make safe and more effective biomedical technologies for applications in highly targeted therapeutics and drug-delivery vehicles. This helps avoid low cellular penetration and accumulation of the drug in intracellular endosomal compartments that are not of interest to a particular therapy. A way to enhance therapeutic efficiency is through nanoparticle loading systems. This study aims to develop low molecular weight (LMW) and high molecular weight (HMW) chitosan and type B gelatin NPs. To enhance cell penetration, the NPs were interfaced with the translocating peptide Buforin II. The obtained nanobioconjugates were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), confocal microscopy, and transmission electron microscopy (TEM). Their size and surface zeta potential were estimated via DLS (Zetasizer Nano). Furthermore, to visualize their endosomal escape, the NPs were marked with the fluorophore Rhodamine B and imaged with the aid of confocal microscopy. The FTIR results showed bands corresponding to the polymers and Buforin II after conjugation. The average NPs diameters were about 250 nm. The zeta potential of the chitosan NPs approached neutrality, which may be problematic due to low colloidal stability. The gelatin zeta potential of −7 mV was closer to the value required for colloidal stability, i.e., ±10 mV. SEM microscopy of LMW and HMW chitosan NPs showed a round-shape and oval morphology, respectively, while the gelatin NPs had a filamentous morphology. SEM also shows agglomerates of the NPs. TEM microscopy results confirmed the LMW chitosan NPs morphology and showed that their nominal size was 5–10 nm. Full article

Reduced graphene oxide (r-GO) has physical–chemical properties like graphene and therefore it can be used for most graphene-based technological applications. r-GO is produced by chemical or thermal reduction of graphene oxide (GO). GO is a highly water-soluble organic compound that can be easily processed in the form of aqueous/alcoholic ink to produce thick self-standing films (i.e., GO paper) or thin coatings supported on a variety of substrates (e.g., polymers, cellulose, glass, silicon, etc.). The best GO reduction technique depends on the substrate chemical/thermal stability, and in the case of thermally unstable substrates (e.g., cellulose), the chemical approach is mandatory. However, traditional reductants, like hydrazine and phenyl-hydrazine, are highly active and therefore detrimental for the substrate. Among the mild reducing agents, L-ascorbic acid (L-aa), a green chemical reductant, has been widely investigated for GO reduction in aqueous solutions. Here, L-aa has been used to convert a GO gel-phase to r-GO by (i) swelling the GO phase with hot water, in order to allow L-aa permeation inside its lamellar structures by diffusion; and (ii) periodically restoring the reductant on the GO layer surface. According to the morphological–structural characterization (SEM, FT-IR, etc.), the proposed approach allowed GO conversion to r-GO, preserving a thin GO interfacial layer essential for a good adhesion. Full article

Resonant modes are important characteristics of the optical properties of photonic crystals since they are responsible for the features in the transmission and reflection spectra as well as the emissivity of quantum emitters inside such structures. We present a resonant modes expansion method applied to a problem of radiating dipoles inside a photonic crystal. In stacked photonic crystal slabs, there is a coupling between the resonances of distinct subsystems and Fabry–Perot resonances. We propose a technique to calculate the coefficients of resonant mode expansion based on the scattering matrix formalism of the Fourier modal method (FMM). The method appears to be convenient since it does not require rigorous normalization of resonant fields or application of perfectly matched layers. Then, we demonstrate the agreement between the resonant modes expansion results and exact FMM solutions. Full article

One of the main challenges in gene therapy is the transport of genetic material into target cells. This is mainly due to the need for overcoming several obstacles like rapid genetic material degradation by the physiological environment, low endosomal escape, and limited cell uptake. A meaningful way to increase the efficacy of genetic material delivery is to incorporate magnetite nanoparticles to transport biomolecules with high biocompatibility and relative ease of handling. Moreover, magnetite offers the possibility of controlled fate by magnetic fields and excretion as ferritin. This study aims to develop a nanostructured platform for the immobilization and intracellular release of nucleic acids for gene therapy applications. The system also co-immobilized the potent cell-penetrating protein OmpA (outer membrane protein A). The delivery of the conjugated material was first transiently tested in vitro in the presence of reducing agents via spectrofluorimetry. This was achieved by the presence of a reducible linker in the nanoplatform where the fluorophore rhodamine B was conjugated for proof-of-concept purposes. Based on the in vitro results, we decided to deliver this to neuroblastoma and Vero cells to confirm an endosomal escape of about 85% as calculated by colocalization. Future experiments will be focused on the hybridization of a gene sequence for the expression of the fluorescent protein mCherry. The obtained nanobioconjugate will also be delivered to cells to evaluate transfection efficiencies. Full article

In this work, catalysts based on TiO₂ modified by fluorination and platinum addition were prepared and evaluated in glycerol oxidation. The materials were characterized by TEM, N₂ physisorption, XRD, UV–Vis DRS, XRF and XPS. It was found that fluorination led to an increase in the surface area of TiO₂, and by platinization treatment, it was possible to obtain a high absorption in the visible region of the electromagnetic spectrum. From these improved properties, 0.5 wt.% Pt-F-TiO₂ was prepared as the best catalyst for the obtention of the highest yield and selectivity towards glyceraldehyde (GAL). It was also observed that the increase in Pt content had a detrimental effect on the effectiveness of fluorinated titania in the glycerol conversion. The fluorination and platinum addition modify some physicochemical properties of TiO₂, thus also modifying the reaction mechanism and selectivity during glycerol oxidation. Full article

Uniform conductive films composed of graphite platelets (GPs) were obtained by spraying a commercial graphite lacquer on low-density polyethylene (LDPE) substrates. According to the scanning electron microscopy investigation and X-ray diffraction analysis, the deposited films are composed of crystalline graphite platelets with an average size of 13.6 nm. The thermoresistive behavior of the GP film on LDPE samples was investigated from 20 to 120 °C. The resistance of the samples increases considerably in the 20–100 °C range and decreases sharply for temperatures above 100 °C. This behavior could be ascribed to the thermal properties of the polymer substrate. Results show that promising materials for thermoresistive applications in flexible electronics can be obtained by combining dielectric polymeric substrates with coatings based on graphite platelets. Full article

This work is devoted to the study of the modes of synthesis of films of nanocrystalline vanadium oxide for the manufacture of resistive memory elements (ReRAM) of neuromorphic systems. The regularities of the influence of pulsed laser deposition modes on the morphology and electrophysical properties of vanadium oxide films were experimentally established considering the technological parameters of the substrate temperature and temperature of postgrowth annealing. Fabrication modes of nanocrystalline vanadium oxide films were determined with the high-resistance state R_HRS = (123.42 ± 21.77) × 10³ Ω, the low-resistance state R_LRS = (5.12 ± 1.36) × 10² Ω, and the ratio R_HRS/R_LRS = 253, for the creation of elements of resistive memory with low power consumption and a wide range of accepted possible resistance values. The results obtained can be used in the development of technological processes for the formation of nanocrystalline films of vanadium oxides for resistive memory elements in neuromorphic systems. Full article

The use of metal immunoprobes, defined as recognition molecules (e.g., antibodies) labeled with metal tags, constitutes an interesting strategy for the analysis of proteins in biological samples. Fluorescent and biocompatible metal nanoclusters (MNC) have been recently established as powerful tags for detection by spectrofluorimetry, but also by elemental mass spectrometry (MS). Detection of such immunoprobes by elemental MS allows not only the qualitative analysis of the proteins but also their absolute quantification. However, the deviation associated with the MNCs polydispersity will limit the analytical precision, particularly in those samples where the concentrations of the sought protein are very low (e.g., single cell analysis). In this work the synthesis of size monodisperse gold nanoclusters (AuNCs) is investigated by using different experimental conditions such as reaction time and temperature, solvent, reducing agent, and pH, among others. Characterization of AuNCs was performed by spectrofluorimetry, dynamic light scattering (DLS) and high resolution transmission electron microscopy (HR-TEM) measurements. Full article

In this work, the titanium oxide nanodots arrays formation was carried out. A current-voltage characteristics study of nanodots showed that the resulting structure switches between high resistance and low resistance states. Additionally, we performed a numerical simulation of the formation of oxide nanodots obtained by the local anodic oxidation method, the results of which showed that the TiO₂ phase dominates on the formed oxide surface. As the oxide goes deeper into the bulk, the Ti₂O₃ and TiO phases appear and the TiO phase prevails near the metal/oxide interface. To confirm the simulation results, the titanium oxide nanodots phase composition was studied by the XPS method, which confirmed the theoretical results. Full article

The proficient functions of diacerein and anti-inflammatory polymers have been utilized to develop sustained release transdermal diacerein nanoemulgel for long-term osteoarthritis treatment by overcoming the deleterious outcomes of drugs associated with the oral route. Natural anti-inflammatory and biodegradable polymers like Chitosan (CHS) and chondroitin sulfate (CS) were used to formulate diacerein nanoparticles (DCR-NPs) through the ionic gelation method. Design Expert software was used for preparation of optimized preparation by investigating the impact of polymers and surfactant concentrations on particle size, PDI and entrapment efficiency employing Response Surface Methodology (RSM). DCR-NPs formulated using CHS, CS and Tween 80 in optimized concentrations depicted spherical nanoparticles with particle size of 320.0 ± 3 nm having PDI, zeta potential and entrapment efficiency of 0.3 ± 0.07, 40 ± 0.3 mV and 82 ± 4.16%, respectively. DCR-NPs were further analyzed for confirmation of electrostatic interactions between polymers and drug through Fourier transform-infrared spectroscopy (FTIR). In vitro studies show 95% release of DCR in 72 h exhibiting the Korsmeyer–Peppas model. For transdermal delivery, the nanoemulgel of optimized DCR-NPs was formulated utilizing argan oil as a permeation enhancer with intrinsic anti-inflammatory properties, providing a synergistic effect to the formulation. Nanoemulgel was characterized in terms of visual appearance, spreadability, drug content and rheological behavior providing sustained release of drug up to 4 days following Higuchi model with improved ex vivo permeation, confirmed by fluorescent microscopy. Concisely, DCR-nanoemulgel sustained the release of drug with good penetration and enhanced therapeutic properties owing to the presence of CHS, CS and argan oil possessing anti-inflammatory attributes. Full article

Semiconductor sol–gel films containing plasmonic nanoparticles are being increasingly used in wet analytics (µ-TAS systems) as functional substrates for surface enhanced Raman spectroscopy (SERS), as optical elements, and as photovoltaic and photocatalytic devices. A local change in the structure of such materials with predictable properties of the modified region opens up new possibilities for the creation of integrated circuits and multifunctional systems. Here, we considered the mechanism of local modification of TiO₂ thin films structure containing plasmon nanoparticles as a result of laser annealing. The material processing was carried out by scanning with a continuous wave (CW) semiconductor laser at a wavelength of 405 nm and at radiation intensity from 35 to 85 kW/cm². The modification region differed in optical characteristics and structural features from the original film. As a result of the laser processing, a heat source was formed that ensured the crystal nucleation and growth of brookite up to an intensity of 55.4 kW/cm². A subsequent increase in intensity led to the transformation of brookite into anatase. The crystal phase formation in the obtained track was accompanied by a change in the relief in its cross section and a decrease in the plasmon resonance peak. The density of the film in the modified region increased, which was accompanied by a decrease in its thickness by 20% from the original film thickness. The disappearance of plasmon resonance in the modified region contributed to a decrease in the absorption capacity and, as a consequence, to a sharp decrease in temperature at the central part of the heat source. Full article

Perovskite solar cells, in which decaphenylcyclopentasilane (DPPS) layers were formed on the surface of a CH₃NH₃PbI₃-based perovskite layer, were developed. The photovoltaic properties were improved by controlling the annealing temperature of the perovskite layer. For perovskite layers annealed at high temperatures in the range of 180–220 °C, the perovskite crystals were densely formed and the surface coverage of the perovskite layer was improved. The DPPS-laminated devices suppressed the formation of PbI₂ crystals, and the stability was improved by the DPPS layer. Furthermore, the conversion efficiencies were improved over extended periods of time. Full article

Effects of co-addition of CuBr₂ and NaCl to CH₃NH₃PbI₃(Cl) perovskite solar cells were investigated on the photovoltaic properties and microstructures. Short-circuit current densities and conversion efficiencies were improved by the simultaneous addition of CuBr₂ and NaCl. In addition, the efficiencies of the devices were maintained after 10 weeks. The perovskite structure changed from a tetragonal to a cubic system by the addition of Na, which resulted in the improvement of the perovskite crystal’s stabilization. Full article

Additive effects of guanidinium [C(NH₂)₃, GA] iodide, formamidinium [CH(NH₂)₂, FA] iodide, and guanidinium chloride to CH₃NH₃PbI₃-based photovoltaic devices were investigated. Short-circuit current densities, open-circuit voltages, series resistances and shunt resistances were improved by the GA addition. The short-circuit current densities were increased by FA addition with GA, and the external quantum efficiencies increased, which resulted in suppression of pinholes in perovskite layers by the GA addition. X-ray diffraction showed that the lattice constants of the perovskite crystals increased by the GA and FA addition, and that the GA substituted partially at the CH₃NH₃-site. Full article

The interaction of quantum emitters with photonic antennas created by nanoscale structures may lead to several interesting phenomena with many important potential applications in current and future technology. There are two distinct regimes of light–matter interaction between a quantum emitter and its modified photonic environment, the weak coupling regime and the strong coupling regime, where the quantum emitter has a completely different spontaneous emission response. In the weak coupling regime, an initially excited quantum emitter shows an exponential spontaneous emission dynamic (Markovian response), but the spontaneous decay rate can be markedly different from the free-space vacuum, and can be either enhanced or suppressed due to the Purcell effect. In the strong coupling regime, there is a coherent exchange of energy between the quantum emitter and its modified nanophotonic environment, which manifests itself in non-exponential spontaneous emission dynamics (non-Markovian response). We investigate the spontaneous emission dynamics of a two-level quantum emitter in proximity to an atomically thin tungsten diselenide (WSe₂) layer at various distances of the emitter from the layer and various free-space decay rates of the emitter. Depending on the distance and the decay rate value, our studies cover the range of the weak to strong coupling regime of the light–matter interaction between the quantum emitter and the electromagnetic continuum modified by the WSe₂ layer. We find that the decay dynamics is Markovian under weak coupling conditions, and it becomes strongly non-Markovian, characterized by oscillatory population emitter dynamics, on the top of the overall population decay, as well as population trapping in the emitter. Besides population evolution, we also discuss the non-Markovian spontaneous emission dynamics using a widely used non-Markovianity measure. Full article

Palladium nanoparticles (PdNPs) are one of the most attractive metal nanomaterials because of their excellent physicochemical properties. PdNPs have been studied for many different applications such as Suzuki cross-coupling reactions, hydrogen purification/storage/sensing, CO oxidation, fuel cells, prodrug activation, and antimicrobial therapy. Recently, PdNPs have been explored as photoabsorbers for photothermal therapy and photoacoustic imaging in the treatment of cancer. Herein, we reported a scalable, efficient, green, and one-step method to synthesize PdNPs. The chitosan polymer was used as a stabilizer and vitamin C was used as a reducing agent. Interestingly, the reaction temperature can be adjusted to the size of PdNPs. When the reaction temperature was increased from 25 °C to 95 °C, the morphology of resulted PdNPs changed from a flower shape to a spherical shape and their nanoparticles’ sizes decreased from 64 nm to 29 nm. The characterization revealed that the obtained PdNPs were relatively uniform in size, shape, and stability in an aqueous solution. Full article

In this study, we exploit films of multiwalled carbon nanotubes (MWCNTs) as the sensing element of new and low-cost sensors for temperature, pressure and humidity. Aqueous solutions of functionalized MWCNTs are vacuum filtered to produce freestanding films of randomly oriented MWCNTs, known as buckypaper, with thickness in the range 200–500 µm. The electric resistance of the buckypaper, patterned in strips with widths of a few mm and lengths of up to a few cm, is investigated as a function of temperature, pressure and humidity. The electric resistance of the buckypaper shows a monotonic decrease for increasing temperature over the 80–380 K range. Owing to the high porosity, the buckypaper structure can be changed by the application of a force. A compressive force applied over the buckypaper surface improves the electric contact between the MWCNTs and results in a decrease in the electric resistance. The exposure of the buckypaper to liquid or vapour water increases its electric resistivity. The experimental data presented in this work confirm that the electrical conduction of a buckypaper is highly sensitive to environmental conditions and that the buckypaper is an interesting material with promising applications in a variety of low-cost sensors with high sensitivity and fast response. Full article

In this work devices based on a MWCNTs-Si heterojunction were realized growing MWCNTs, by chemical vapor deposition, on an n-type Si substrate with the top and bottom surfaces covered by 140 nm thick Si₃N₄ layers. Two metal contacts, realized on the top and back of the Si surface, were used to perform I-V measurements of the vertical heterostructure. The photocurrent behavior, obtained by light illumination, was studied as a function of the thickness of the MWCNTs layer. A planar quantum efficiency map of the device was obtained by I-V measure when the active area of the device was rastered by a 1 mm diameter light spot. The thickness reduction of the MWCNTs was realized by adhesive tape. We found that the photocurrent intensity increased when the density of the MWCNTs layer was decreased. To check the substrate coverage by the MWCNTs, scanning electron microscope images were taken. Full article

Lead (Pb) is one of the highly persistent and major toxic health hazards listed by various health organizations. A stable, specific, and simple sensor which can rapidly detect Pb in drinking water is required urgently. To this end, we have prepared stable and uniformly sized colloidal silver nanoparticles (AgNPs) using citric acid for the color-based sensing of Pb in water samples. The synthesized AgNPs are characterized by UV-vis spectroscopy, DLS-Zeta, and TEM to access their optical and morphological properties. The cit-AgNPs have shown a great affinity/selectivity towards Pb over Cd, Mn, Cr, Fe, Co, Pb, Hg, Zn, and Ti ions. Thus, based on the interaction of cit-AgNPs and Pb, a colorimetric sensor for selective, specific, and expeditious detection of Pb ions has been developed. Full article

Phosphate triesters are cleaved by gold nanoparticles functionalized with metal complexes (Zn(II), Cu(II), Co(II), Co(III), Eu(III), Yt(III), Zr(IV)) of triazacyclonononane and cyclen ligands with a mononuclear mechanism with impressive rate accelerations with respect to the uncatalyzed processes, constituting a remarkable example of nerve agents hydrolyzing nanoazymes. Full article

Calcium carbonate nanoparticles have salient properties, such as biocompatibility, pH responsiveness, and the ability to alkalinize a tumor, thereby reducing metastasis. A combination therapy regimen is normative for breast cancer, and besides its side effects, toxic vehicles are required for certain drugs. This study is aimed to transform the readily available Blood cockle shells (Anadara granosa) to calcium carbonate nanoparticles (CSCaCO₃NP), loading them with Gefitinib (GEF) and Paclitaxel (PTXL). Facile top-down synthesis of CSCaCO₃NP is comprised of grinding, sieving, and stirring with Tween 80, followed by filtration and finally dry milling for 120 h. A ratio of 1 + 0.5:25 of GEF+PTXL: CSCaCO₃NP in an equal admixture of DMSO and 0.05% Tween 80 buffer was used for drug loading. Loading content (%) and encapsulation efficiency (%) for GEF and PTXL in dual drug-loaded NP (GEF-PTXL-CSCaCO₃NP) was 1.98 ± 0.11, 50.01 ± 2.18 and 0.92 ± 0.01, 45.60 ± 0.32. Field emission scanning electron micrographs revealed that the nanoparticles were almost spherical with the average diameter (nm) measuring 63.96 ± 22.3 and 87.20 ± 26.66 for CSCaCO₃NP, and GEF-PTXL-CSCaCO₃NP, respectively. The Dynamic Light Scattering data gives the average diameter of CSCaCO₃NP and GEF-PTXL-CSCaCO₃NP as 179 ± 10.9 (nm), and 274 ± 23.22 (nm), and Zeta potential was −17 ± 1.15 (mV) and −10.30 ± 1.7 (mV), respectively. Fourier-transform Infrared spectroscopy proves that CSCaCO₃NP have been loaded with the drugs. X-Ray Diffraction data indicate that the aragonite phase is unaltered. N₂ adsorption-desorption isotherms reveals that CSCaCO₃NP are mesoporous and that the surface area was reduced from 10.68 ± 0.22 to 9.88 ± 0.24 m²/g after drug loading. For the first time, this work will describe the process that enabled to synthesize CSCaCO₃NP, which was used as a carrier to load GEF and PTXL and its salient characteristics. Full article

The encapsulation of biomolecules and microorganisms into liposomes is useful for several biological and biomedical applications. For instance, it is possible to encapsulate pharmacological compounds to increase properties such as therapeutic effectiveness, circulation times, and biocompatibility. Here, we are interested in encapsulating yeast cells expressing translocating peptide molecules on their surfaces. This is with the final intention of separating yeasts with translocating activity from those with other types of membrane activities. To accomplish this, we designed a microfluidic system for the synthesis of giant liposomes (100–150 µm in diameter) based on the droplet generation of double emulsions (water-in-oil-in-water) as templates. Giant liposomes were selected here due to their size, lipid structure (unilamellar), and the ability to control the internal content, which closely mimics, albeit in a more simplified manner, the structural organization of living cells. The microfluidic device comprises a W/O/W junction equipped with three sets of inlets, the main channel, and an output channel at an angle of 30°. The system’s performance was evaluated in silico by implementing a Two-Phase Flow, Level Set model where the flow rate ratios of the continuous and dispersed phases were altered until the droplet was formed. Next, interaction with yeasts was achieved by a Y-junction geometry with two 0.5-mm-length inlets at 45°. The interaction was simulated with the aid of a Mixture Model. Maximum velocity was obtained at the center of the channel and complete mixing at the outlet, indicating high interaction levels. Finally, we implemented an inertial geometry using a Particle Tracing Flow Focusing Model to study the molecules’ separation. Full article

Graphene has attracted considerable interest as a prospective material for future electronics and opto-electronics. Here, the synthesis process of large area few layers graphene by Atmospheric Pressure Chemical Vapor Deposition (APCVD) technique is demonstrated. Quality assessments of graphene are performed and confirmed by Raman analysis and optical spectroscopy. Next, graphene was transferred on Polyethylene Terephthalate (PET) substrates and implemented as transparent conductive electrode in flexible Polymer Dispersed Liquid Crystal (PDLC) devices. Their electro-optical properties, such as voltage-dependent transmittance and flexibility behavior are measured and discussed. The stability of the sheet resistance after 1200 bending tests of graphene/PET structure is demonstrated. The obtained results open a great potential of graphene integration into the next generation Indium Tin Oxide (ITO) free flexible and stretchable optoelectronics. Full article

In the presented work, we would like to introduce a new concept of a 2D solid solvent. This is a material, capable of selective ion or molecules capturing thanks to its developed surface, which is treated as deposited on a substrate (usually spherical nano-silica or mesoporous silica) 2D bi- or multi-component layer. The last one consists of two main components—active anchoring units and passive spacers that are surface analogues of solute and solvent in an ordinary solution. Whereas silica substrate, anchoring units, and spacers are connected and act cooperatively for one final goal, we consider to describe them as one part. In our work, we will clarify a definition of solid solvents as well as show some examples of them and their usage. Full article

The endohedral chemical functionalization of single-walled carbon nanotubes (SWCNTs) allows for tuning their electronic properties toward applications. It was demonstrated that SWCNTs can be filled with elementary substances, chemical compounds and molecules. In this work, we performed the filling of SWCNTs with metal halogenide (cobalt iodide, CoI₂) and metal carbide (nickel carbide, Ni₃C). The filling of SWCNTs with CoI₂ was conducted by the melt method. The filling of SWCNTs with Ni₃C was performed by the thermal treatment of nickelocene-filled nanotubes. The filled SWCNTs were investigated by the high-resolution transmission electron microscopy (HRTEM), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). The HRTEM data prove the encapsulation of compounds inside the SWCNTs. By combining the Raman spectroscopy and XPS data, it was shown that the encapsulated CoI₂ causes p-doping of nanotubes accompanied by the downshift of the Fermi level of nanotubes. The embedded Ni₃C leads to n-doping of SWCNTs with upshifting of the Fermi level of nanotubes. The obtained results allow for applying filled SWCNTs in arange of fields such as nanoelectronics, energy storage, sensors, catalysis and biomedicine. Full article

Manganese is the biggest concern in Bangladesh after Arsenic, as almost 50% area contains groundwater with Mn concentrations greater than the WHO drinking water guidelines. The previous studies suggested that γ-FeOOH could remove Mn effectively from water. However, those studies were conducted at higher pH levels and not in natural conditions. Additionally, the practical applicability of the Mn removal methods was not discussed. Moreover, additional separation processes required to separate the adsorbents and precipitations are not environmentally friendly. Therefore, to improve the Mn removal efficiency at natural pH levels and other natural water conditions, we examined Mn removal by adsorption technology using polymer gel composites. The gel composites were a cationic gel composite, N,N’-dimethylamino propylacrylamide, methyl chloride quaternary (DMAPAAQ), loaded with iron hydroxide (DMAPAAQ + FeOOH), and a non-ionic gel composite, N,N’-Dimethylacrylamide (DMAA), loaded with iron hydroxide (DMAA + FeOOH). DMAPAAQ + FeOOH gel contains 62.01 wt% of γ-FeOOH in its polymer structures because of the unique preparation method and this gel showed better As removal efficiency than the other adsorbents at natural conditions ensuring its environmental friendliness. Our results suggest that the cationic gel composite, DMAPAAQ + FeOOH, removed Mn more than that of DMAA + FeOOH because the content of γ-FeOOH particles was higher in the gel structure of DMAPAAQ + FeOOH. Besides the polymer component of DMAPAAQ + FeOOH contributing to the adsorption of Mn, it carried the higher amount of γ-FeOOH components, which helped to further increase Mn removal. Our results also suggested that the presence of As did not have any effect on the adsorption of Mn with DMAPAAQ + FeOOH gel composite because the polymeric component (DMAPAAQ) adsorbed As and the γ-FeOOH particles adsorbed Mn, which provides the basis for simultaneous adsorption of As and Mn. This research is a base for the simultaneous removal of harmful components such as As, Mn, Cr, Cd, and more. Full article

Breast cancer is the most common type of cancer that affects and kills women annually in the world. It impacts more than two million women and is responsible for the death of approximately 25% of them. Almost 70% of breast cancer diagnoses are positive for hormone receptor and have a good prognosis. However, resistance to drugs used in hormone therapy, such as tamoxifen, is usual and about 40% of recurrences do not respond to it. In some cases, the overexpression of the HOXB7 gene is related to this mechanism and its silencing can reverse the response to tamoxifen. Here, we used copolymer-coated calcium phosphate nanoparticles to deliver HOXB7 siRNA and restore the sensitization of MCF7 cells to tamoxifen. Nanoparticle synthesis and characterization were performed, and cell viability and gene expression were evaluated. Hybrid nanoparticle presented a Z-average diameter of 83 nm and polydispersity index (PdI) of 0.07, while showing good entrapment of siRNA molecules. We also observed a decrease in HOXB7 gene expression (~65%) promoted by the siRNA molecule delivered by the nanoparticles. The gene silencing has good correlation to the cell viability assay: a reduction in breast cancer viability was observed in 48 (31%) and 72 (38%) hours. As for the co-treatment with tamoxifen, cell viability started dropping after 15 h, which did not occur in the treatment only with Tamoxifen at the same concentration. This result indicates that the biological effect was possibly related to RNAi effect and suggests that HOXB7 may be promoting cell sensitization to tamoxifen without reducing cell viability. Overall, these results suggest that the nanostructured system was effective in promoting gene silencing and that the co-therapy can be a promising tool for the treatment of hormone receptor-positive breast cancers. Full article

The delivery of bioactive compounds is often improved by their encapsulation within systems based on different materials, such as polymers and phospholipids. In this regard, one of the most attractive vehicles are liposomes, which can be produced by the self-assembly of phospholipids in aqueous buffered systems. Encapsulation of therapeutic magnetite nanoparticles (MNPs) within liposomes can be accomplished by direct translocation of their lipid bilayer by surface conjugation of potent translocating peptides (and proteins) such as Buforin-II and OmpA. Here, we put forward the notion that to achieve reproducibility and optimize this process, it is possible to develop microfluidic systems that use flow-focusing methods to manipulate the interaction of suspended MNPs (ferrofluids) with the liposomes. With that in mind, we have developed an in silico approach to predict the performance of microfluidic devices specifically designed for the encapsulation process. This was done by running multiphysics simulations in COMSOL to evaluate the macroscopic flow of liposomes and suspended MNPs via a multiphase mixture model. Moreover, we estimated the corresponding interaction using a chemical reaction model based on embedding the Michaelis–Menten equation within the diluted species module’s transport. In this case, the enzymes-substrate interaction was considered similar to that of the MNPs-liposome. As a result, we were able to approach saturation kinetics that resemble that obtained experimentally for the uptake of functionalized MNPs. Future work will be directed towards refining the model by considering more details on the possible stages during the interaction of the involved intermediates. Full article

In this study, eletrolitical copper powder (Cu) was initially mixed with the aqueous solution of graphene oxide (GO); later, the mixture underwent mechanical stirring for 1 h, vacuum filtration, and drying for 42 h. The final concentration of GO in the composite was 0.3%wt. Through scanning electron microscopy (SEM), it was possible to observe the homogeneous dispersion of graphene sheets between copper particles, without the presence of agglomerates. In addition, X-ray diffraction (XRD) of the pure samples and after mixing revealed that there was no oxidation of the copper and the absence of peaks related to other elements, confirming the high purity of the copper used. Still, by XRD, it was possible to analyze that the graphene oxide produced was formed by stacking layers of graphene owing to the appearance of a diffraction peak referring to the plane (002), which was confirmed by Raman spectroscopy performed in GO from the appearance of the 2D bands. Fourier transform infrared spectroscopy (FTIR) allowed the identification of the vibrational spectra referring to the hydroxyl, carbonyl, and epoxy functional groups in GO, confirming that the oxidation process was effective in inserting functional groups in the basal graphical plane. Through the GO thermogravimetric analysis (TGA), it was possible to identify a significant loss of mass of approximately 30% at temperatures below 100 °C; referring to the elimination of water molecules, the most stable functional groups were eliminated at temperatures between 600 °C and 800 °C. Full article

Magnetite nanoparticles (MNPs) have been considered for several applications in drug delivery. However, the main challenge is to assure high cell-penetration levels, especially when dealing with cargoes that show limited membrane passing. A strategy is to encapsulate the MNPs into liposomes to form magnetoliposomes (MLs) capable of fusing with membranes to achieve high delivery rates. MLs have therefore been used as carriers in the biomedical field due to their ability to release active molecules that can be used in treatments of diverse diseases. There are several techniques to produce such encapsulates, however, the main challenge is that the process often leads to an important fraction of non-encapsulated MNPs. Purification of such a fraction is challenging because of the small size difference between the particles and the MLs and the reduced magnetic responsiveness. Seeking to obtain pure MLs with potential use in the medical field, the following study presents finite element simulations using COMSOL Multiphysics of two purification methods. Accordingly, we implemented the magnetic and asymmetric pinched flow fractionation (AsPFF) separation systems to evaluate their purification efficiencies considering operation parameters such as the Flow Rate Ratio (FRR) and Total Velocity Ratio (TVR). Additionally, a mixture interaction approach was used to model the MNPs as a dispersed ferrofluid phase. This was compared with a particle tracing approach where MNPs are considered individual entities subjected to hydrodynamic forces. The results show efficiencies between 60% and 90% for both separation methods, which confirms their feasibility to improve and optimize the purification of MLs in a high throughput manner. Full article

Endothelialization is required to maintain patency in tissue-engineered vascular grafts (TEVGs). Ligand surface functionalization is intended to induce the adhesion and spreading of Endothelial Cells (ECs). ECs surface adhesion occurs through the integrin-ligand interaction. Here, we propose a chemo-mechanical model, using COMSOL Multiphysics 5.5, to study the optimal ligand distribution in order to improve interaction under laminar blood flow. The proposed model elucidates the role of binding forces and flow velocities over cell spreading as a function of the relevant ligand concentration. This model can contribute to optimizing the surface functionalization of TEVGs for promoting successful endothelialization. Full article

Improved corrosion protection of low-carbon steel was achieved by barrier non-toxic sol–gel multilayered structures composed of a ZrO₂ top coating and TiO₂ underlayers. The zirconium precursor solution was maintained as constant, whereas the TiO₂ solution composition was modified with two different types of polymers, which were added separately to the starting titanium solution. The phase composition, morphology and corrosion protective properties were analyzed by X-ray diffraction spectroscopy (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and atomic force microscopy (AFM). Hydrophobicity properties were evaluated by measuring the contact angle with a Ramé-Hart automated goniometer. The potentiodynamic polarization technique was used to determine the corrosion resistance and protective ability of the coatings in a 5% NaCl solution. Both polymeric modifications, as compared to the non-modified titania layer, demonstrated positive effects on the corrosion properties of the structures at conditions of external polarization. Due to the amorphous structure of the zirconia layer and its relatively dense, hydrophobic surface, all of the samples extended the service life of low-carbon steel in a model corrosion medium. The feasibility of the sol–gel deposition method makes it possible to prepare oxide coatings with appropriate surface properties, which ensures high corrosion resistance. Full article

Their low density and high specific stiffness and impact energy/vibration absorption ability make Al-based metal foams promising materials in applications for which a light weight and energy/vibration absorption abilities are crucial. In view of these properties, Al-based foams can be extremely interesting as cores in cast components in order to improve their performances and simplify their whole technological process. However, both in the scientific literature and in technological application, this topic is still poorly explored. In the present work, Al-based metal foams (Cymat foams and Havel metal foams in the form of rectangular bars) are used in a gravity casting experiment of an Al-Si-Cu-Mg alloy (EN AB-46400). The foams were fully characterized before and after insertion in casting. Porosity, cell wall and external skin thickness, microstructure, infiltration degree, and the quality of the interface between the foam core and the dense cast shell, have been investigated by means of optical microscopy and scanning electron microscopy equipped with energy dispersive spectroscopy (SEM-EDS). The analyses evidenced that a continuous and thick external skin protect the foam from infiltration by molten metal, preserving the initial porosity and insert shape. A detailed analysis of the foam’s external skin highlights that the composition of this external skin is crucial for the obtaining of a good joining between the molten metal and the Al foam core. In fact, the presence of Mg oxides on the foam surface prevents bonding, and maintains a gap between the core and the shell. This point opens up the opportunity to design innovative surface modifications for this external skin as promising strategies for the optimization of cast components with a foam core. Full article

In the present work we have investigated the oxysulfate fraction of spent lead–acid battery pastes in search of an optimal method for its recycling. For this purpose, desulfurization and leaching were performed in one step by simultaneously adding aqueous solutions of sodium citrate and citric acid at varying temperatures (25–100 °С) and heat treatment times (1–2 h) in order to obtain a lead citrate precursor for direct application in the production of lead oxide powder. Two types of lead citrate were obtained: Pb(C₆H₆O₇).H₂O and Pb₃(C₆H₅O₇)₂.3H₂O. After calcination at low temperature (300 °C), these precursors formed a nanosized lead oxide powder. X-ray diffraction analysis (XRD) was performed at each stage of the study to monitor the changes in phase composition and crystallite size of the synthesized powder. Morphological features were investigated by scanning electron microscopy (SEM). An additional differential thermal analysis (DTA) was performed to determine the type of the obtained lead citrate. Finely dispersed lead oxide powders were formed. The measured crystallite sizes of the two main phases were 30–50 nm for β-PbO₍₁₁₁₎ and 40–60 nm for Pb₍₁₁₁₎. Full article

The influence of alkali metals (Na, K) or transition metals (Co, Cr, Cu, and Y) incorporated into perovskite crystal on the electronic structures, spectroscopic, and magnetic properties, and thermodynamic properties was investigated by first-principles calculation. Incorporation of Na or K into the perovskite crystal generated 3s, 3p, 4s, and 4p orbitals of Na or K above the conduction band, which promoted the charge transfer from alkali metal to the conduction band, accelerating the electron diffusion related to the photovoltaic properties. For the Cr, Cu, and Y-incorporated perovskite crystals, the electron density distribution of d-p hybrid orbital on the transition metal and iodine halogen ligand were delocalized at frontier orbital. The electronic correlation worked in between the localized spin on 3d orbital of the metal, and the itinerant carriers on the 5p orbital of the iodine halogen ligand and the 6p orbital of the lead atom in the perovskite crystal. The vibration behavior of the Raman and infrared spectra were associated with change of polarization and slight distortion near the coordination structure. The considerable splitting of chemical shift of ¹²⁷I-NMR and ²⁰⁷Pb-NMR in the magnetic field was caused by crystal field splitting with the Jahn-Teller effect with nearest-neighbor nuclear quadrupole interaction based on the charge distribution. Decrease of the Gibbs free energy and entropy indicated the thermodynamic stabilization without scattering carrier diffusion as phonon effectiveness. The decrease of the entropy was based on a slight change of stretching vibration mode of Pb–I bond with vending mode of N–H and C–H bonds in the infrared and Raman spectra. The minor addition of alkali metal or transition metal into the perovskite crystal would improve the photovoltaic properties, open voltage related to band gap, and short-circuit current density based on the carrier diffusion with phonon effectiveness. Full article

In this paper, the main issues concerning the possibility of the organization of Mn₁₂-based single-molecule magnets (SMMs) on the surface of silica nanostructures with the preservation of its structure and magnetic properties were summarized. The aging effects on structural and magnetic properties in Mn₁₂-stearate SMMs deposited on the surface of spherical silica nanoparticles were also discussed. Full article

For in vivo application of mRNA therapeutics, the development of mRNA nanocarriers that protect mRNA from enzymatic degradation is needed. While current nanocarrier development focuses on fine-tuning the chemical structure of its components, including lipids and polymers, herein, we propose a novel strategy to design stable mRNA nanocarriers by structuring mRNA inside the nanocarriers. Firstly, several mRNA strands were crosslinked with each other using RNA crosslinkers that hybridize to mRNA strands, to prepare mRNA nanoassemblies (NAs). Then, we mixed NAs with poly(ethylene glycol) (PEG)-polycation block copolymers to prepare core–shell-structured polyplex micelles (PMs), composed of PEG shell and mRNA-containing core. Notably, PM-loading NAs (NA/m) exhibited enhanced stability against enzymatic attack and polyion exchange reaction compared to that loading naïve mRNA (naïve/m). According to mechanistic analyses, NA/m possessed a shell with a denser PEG layer and a core with more condensed mRNA compared to naïve/m. As a result, NA/m induced more efficient protein expression after introduction to cultured cells and mouse brain, compared to naïve/m. While newly developed materials need long processes before their clinical approval, our strategy is effective in improving stability and the mRNA introduction efficiency of existing mRNA nanocarriers just by structuring mRNA without the use of additional materials. Full article

Essential oils (EOs), which are complex biomolecules composed of volatile compounds, have emerged as a new strategy to deal with bacterial infections and as a valid alternative to synthetic drugs. Here, we report the production and modification of wet-spun microfibers made of cellulose acetate (CA) and polycaprolactone (PCL) with the EOs cinnamon leaf oil (CLO), cajeput oil (CJO), and clove oil (CO). These were selected from a group of 20 EOs according to their minimal inhibitory concentration (MIC) against Staphylococcus aureus (<22.4 mg/mL) and Escherichia coli (<11.2 mg/mL) bacteria. Microfibers were produced by wet-spinning at an extrusion rate of 0.5 mL/h directly into an ethanol coagulation bath. EOs loading was accomplished by immersion in ethanol solutions containing the EOs at 2xMIC. Incorporation was confirmed by UV-Visible spectroscopy and Fourier-transformed infrared spectroscopy. After 72 h of incubation, microfibers contained 14%, 66% and 76% of the MIC values of CLO, CO and CJO, respectively. Unloaded and loaded microfibers were characterized as uniform and homogeneous; no significant differences were detected. EO-modified microfibers were effective against the tested bacteria. Considering the amount immobilized, CLO-containing fibers were deemed the most effective from the group, suggesting a superior affinity of the EOs active groups towards the CA/PCL matrix. These results indicate that CA/PCL microfibers loaded with EOs have potential for biomedical application in which infection control is the target. Full article

RNA interference (RNAi) has emerged as a promising therapeutic approach for the treatment of a wide range of disorders. Small interfering RNAs (siRNAs), i.e., non-coding double-stranded RNA molecules, have been mainly used for RNAi. Because siRNA is susceptible to enzymatic degradation and is rapidly cleared from the bloodstream, the success of RNAi is strongly related to the design of efficient delivery technologies. Among auspicious carriers for siRNA, polymeric micelles self-assembled by polyion complexation between block ionomers and siRNA have attracted much attention due to their well-defined size, efficient complexation and potential for delivery in vivo. In this regard, we have recently demonstrated that the polycation flexibility influences the complexation with single stranded RNA molecules, affecting the delivery capability of the resulting micelles. On the other hand, the effects of the catiomer flexibility on micelles loading double stranded siRNA remains unknown. Thus, herein, we studied the effects of the polycation backbone flexibility on siRNA-loaded polyion complex (PIC) micelles by using complementary block copolymers, i.e., the relatively flexible poly(ethylene glycol)-poly(glycidylbutylamine) (PEG-PGBA) and the more rigid PEG-poly(L-lysine) (PEG-PLL). By mixing these polymers with siRNA at different N/P ratios, we found that PEG-PGBA effectively promoted self-assembly of PIC micelles at lower N/P ratios and lower siRNA concentrations than PEG-PLL. Computational studies of siRNA binding with polycations and PEG-polycations further supported the favorable binding process of flexible polycations with siRNA. The micelles based on PEG-PGBA were stable in physiological conditions and promoted effective intracellular delivery of siRNA for efficient gene knockdown. Our results indicate the importance of polycation flexibility for the assembly of PIC micelles with siRNA, and its potential for developing innovative carrier systems. Full article

In this study, the four-wave mixing (FWM) spectrum of a strongly pumped hybrid structure is theoretically examined. The hybrid structure consists of an asymmetric double semiconductor quantum dot (SQD) molecule and a spherical metal nanoparticle (MNP), which are coupled together via long-range Coulomb interaction. Having as a starting point the Hamiltonian of the system, in the dipole and the rotating-wave approximations, we derive a set of nonlinear density matrix equations, which are numerically solved, in the steady-state limit, and then the FWM coefficient is calculated within a range of values of the pump–probe field detuning. The spectral response of the FWM coefficient is investigated, for different values of the pump-field detuning, the electron-tunneling rate, and the energy gap between the upper states in the energy-level scheme of the double SQD molecule, while the interparticle distance between the two components of the structure is modified. Full article

Magnetite nanoparticles (MNPs) have been considered for several applications in drug delivery. However, the main challenge is to assure high cell-penetration levels, especially when dealing with cargoes that show limited membrane passing. A strategy is to encapsulate the MNPs into liposomes to form magnetoliposomes (MLs) capable of fusing with membranes to achieve high delivery rates. MLs have therefore been used as carriers in the biomedical field due to their ability to release active molecules that can be used in treatments of diverse diseases. There are several techniques to produce such encapsulates, however, the main challenge is that the process often leads to an important fraction of non-encapsulated MNPs. Purification of such a fraction is challenging because of the small size difference between the particles and the MLs and the reduced magnetic responsiveness. Seeking to obtain pure MLs with potential use in the medical field, the following study presents finite element simulations using COMSOL Multiphysics of two purification methods. Accordingly, we implemented the magnetic and asymmetric pinched flow fractionation (AsPFF) separation systems to evaluate their purification efficiencies considering operation parameters such as the Flow Rate Ratio (FRR) and Total Velocity Ratio (TVR). Additionally, a mixture interaction approach was used to model the MNPs as a dispersed ferrofluid phase. This was compared with a particle tracing approach where MNPs are considered individual entities subjected to hydrodynamic forces. The results show efficiencies between 60% and 90% for both separation methods, which confirms their feasibility to improve and optimize the purification of MLs in a high throughput manner. Full article

We apply the method of rapid adiabatic passage to a semiconductor quantum dot coupled to a plasmonic nanostructure, specifically a metal nanoparticle, and examine the excitonic state preparation efficiency for different distances between the quantum dot and the metal nanoparticle. In particular, results for the interaction of the coupled quantum dot–metal nanoparticle structure with linearly chirped Gaussian laser pulses are presented. We find that efficient population transfer occurs for a wide range of system parameters, like pulse areas and chirp rates, for different distances between the quantum dot and the metal nanoparticle. The presence of the metal nanoparticle influences significantly the population transfer to the exciton state, when the distance between the quantum dot and the metal nanoparticle becomes small. Full article

Zinc-tin oxide (ZTO) nanostructures appear as one of the most promising material systems for a new generation of nanodevices. In this work, a microwave-assisted hydrothermal synthesis to produce different shapes of Zn₂SnO₄ nanostructures (nanoparticles, octahedrons and nanoplates) is presented. Reproducible and homogeneous results were obtained with the advantage of reducing up to 20 h the synthesis time when compared to using a conventional oven. Furthermore, the photocatalytic activity of the Zn₂SnO₄ nanostructures in the degradation of rhodamine B under UV light was studied. Zn₂SnO₄ nanoparticles demonstrated better performance with >90% of degradation being achieved in 2.5 h. Full article

As the diversity of nanomaterials is wide and their size can vary by 2 orders of magnitude (1−100 nm), the development of new and advanced analytical tools for their in-depth characterization is of paramount importance, allowing a fundamental understanding of their structure, further alteration and degree of chemical surface functionalization. Herein, we present a new strategy for characterization of gold nanorods (GNRs) that are of specific interest for biomedical applications due to their unique size-dependent longitudinal surface plasmon resonance band in the visible to near-infrared spectral region. More precisely, we characterized GNRs conjugated with short and long synthetic glycopolymers for biosensing of lectins in terms of particle size, coating thickness, and/or mobility properties in comparison with the bare GNRs. This endeavor requires a multidisciplinary approach including a new comprehensive set of fit-for-purpose analytical tools being high-resolution single-particle inductively coupled plasma-mass spectrometry (HR-spICP-MS) and electrical asymmetric-flow field-flow-fractionation hyphenated to a multi-angle light scattering detector (EAF4-MALS). GNRs were separated and characterized via EAF4-MALS in terms of their size and charge, while HR-spICP-MS provided information on the particle number density, size, size distribution, and the dimensional characterization. In addition, EAF4-MALS appears to be suitable for estimating coating thickness of glycoconjugated GNRs. Full article