Micro

Graphene, a two-dimensional material with remarkable electrical, thermal, and mechanical properties, has revolutionized the fields of electronics, energy storage, and nanotechnology. This review presents a comprehensive analysis of graphene synthesis techniques, which can be classified into two primary approaches: top-down and bottom-up. Top-down methods, such as mechanical exfoliation, oxidation-reduction, unzipping carbon nanotubes, and liquid-phase exfoliation, are highlighted for their scalability and cost-effectiveness, albeit with challenges in controlling defects and uniformity. In contrast, bottom-up methods, including chemical vapor deposition (CVD), arc discharge, and epitaxial growth on silicon carbide, offer superior structural control and quality but are often constrained by high costs and limited scalability. The interplay between synthesis parameters, material properties, and application requirements is critically examined to provide insights into optimizing graphene production. This review also emphasizes the growing demand for sustainable and environmentally friendly approaches, aligning with the global push for green nanotechnology. By synthesizing current advancements and identifying critical research gaps, this work offers a roadmap for selecting the most suitable synthesis techniques and fostering innovations in scalable and high-quality graphene production. The findings serve as a valuable resource for researchers and industries aiming to harness graphene’s full potential in diverse technological applications. Full article

The growing threat of antimicrobial resistance has necessitated the development of alternative, non-antibiotic therapies for effective microbial control. Antimicrobial photodynamic therapy, which uses photosensitizers activated by light to generate reactive oxygen species, offers a promising solution. Among natural photosensitizers, curcumin, a polyphenolic compound from Curcuma longa, has demonstrated broad-spectrum antimicrobial activity through reactive oxygen species-mediated membrane disruption and intracellular damage. However, curcumin’s poor water solubility, low stability, and limited bioavailability hinder its clinical utility. Nanotechnology has emerged as a transformative strategy to overcome these limitations. This review comprehensively explores advances in nanocurcumin- and curcumin-loaded nanoparticles, highlighting their physicochemical enhancements, photodynamic mechanisms, and antimicrobial efficacy against multidrug-resistant and biofilm-associated pathogens. A range of nanocarriers, including chitosan, liposomes, nanobubbles, hybrid metal composites, metal–organic frameworks, and covalent organic frameworks, demonstrate improved microbial targeting, light activation efficiency, and therapeutic outcomes. Applications span wound healing, dental disinfection, food preservation, water treatment, and medical device sterilization. Conclusions and future directions are given, emphasizing the integration of smart nanocarriers and combinatorial therapies to enhance curcumin’s clinical translation. Full article

Nanomaterials are materials in which at least one dimension in three-dimensional space is at the nanoscale. In recent years, nano-alumina has attracted much attention due to its large specific surface area and pore volume, as well as novel optical, magnetic, electronic, and catalytic properties. This review summarizes the preparation methods of nano-alumina based on the basic phases and properties of alumina materials, focusing on one-dimensional, two-dimensional, and three-dimensional nano-alumina preparation methods, which can provide some theoretical guidance for the subsequent development of efficient nano-alumina materials. Finally, the application of nano-alumina materials in catalysis is reviewed, and some suggestions are provided for improving the use of nano-alumina in the catalysis field. Full article

Over the last few decades, the growing demand for sustainable resources has made biopolymers increasingly popular, as they offer an eco-friendly alternative to conventional synthetic polymers, which are often associated with environmental issues such as the formation of microplastics and toxic substances. Functionalization of biomaterials involves modifying their physical, chemical, or biological properties to improve their performance for specific applications. Cellulose and bacterial cellulose are biopolymers of interest, due to the plethora of hydroxyl groups, their high surface area, and high porosity, which makes them ideal candidates for several applications. However, there are applications, which require precise control of their wetting properties. In this review, we present the most effective fabrication methods for modifying both the morphology and the chemical properties of cellulose and bacterial cellulose, towards the realization of superhydrophobic bacterial cellulose films and surfaces. Such materials can find a wide variety of applications, yet in this review we target and discuss applications deriving from the wettability control, such as antibacterial surfaces, wound healing films, and separation media. Full article

The encapsulation of bioactive compounds using proteins as wall materials has emerged as an effective strategy to enhance their stability, bioavailability, and controlled release. Proteins offer unique functional properties, including amphiphilic behavior, gel-forming ability, and interactions with bioactives, making them ideal candidates for encapsulation. Animal-derived proteins, such as whey and casein, exhibit superior performance in stabilizing lipophilic compounds, whereas plant proteins, including soy and pea protein, demonstrate greater affinity for hydrophilic bioactives. Advances in protein modification and the formation of protein–polysaccharide complexes have further improved encapsulation efficiency, particularly for heat- and pH-sensitive compounds. This review explores the physicochemical characteristics of proteins used in encapsulation, the interactions between proteins and bioactives, and the main encapsulation techniques, including spray drying, complex coacervation, nanoemulsions, and electrospinning. Furthermore, the potential applications of encapsulated bioactives in functional foods, pharmaceuticals, and nutraceuticals are discussed, highlighting the role of emerging technologies in optimizing delivery systems. Understanding the synergy between proteins, bioactives, and encapsulation methods is essential for developing more stable, bioavailable, and sustainable functional products. Full article

This study evaluates the effect of zirconium (Zr) incorporation on the structural, microstructural, and functional properties of lead-free ceramics based on the 0.95(Bi_0.5Na_0.5)TiO₃–0.05BaTiO₃ (BNT–5BT) system. Two distinct doping strategies were investigated: (i) the substitutional incorporation of Zr⁴⁺ at the Ti⁴⁺ site (BNT–5BT–xZr_sub), and (ii) the addition of ZrO₂ in excess (BNT–5BT–xZr_exc). The samples were synthesized via conventional solid-state reaction and characterized using X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM/EDS), and electrical measurements, including dielectric, ferroelectric, and piezoelectric responses. Both doping routes were found to influence phase stability and electromechanical performance. Substitutional doping notably reduced the coercive field while preserving high remanent polarization, resulting in an enhanced piezoelectric coefficient (d₃₃). These results highlight the potential of Zr-modified BNT–5BT ceramics for lead-free energy harvesting applications. Full article

Antifouling coatings are integral to the maritime economy. The efficacy of the applied painting system is closely correlated with susceptibility to fouling and the adhesion strength of contaminants. A fouled hull might result in an elevated fuel consumption and journey expenses. Biofouling on ship hulls also has detrimental environmental consequences due to the release of biocides during maritime travel. Therefore, it is imperative to develop eco-friendly antifouling paints that inhibit the robust adhesion of marine organisms. This study aimed to assess a biocide-free antifouling coating formulated with polymers intended to diminish molecular adhesion interactions between marine species’ adhesives and the coating. The evaluation included laboratory corrosion experiments in artificial seawater and the immersion of samples in a marine environment in Attica, Greece, for varying durations. The research indicates that an antifouling coating applied to naval steel in an artificial seawater solution improves corrosion resistance by more than 60%. The conductive polymer covering, comprising polyaniline and graphene oxide, diminishes corrosion current values, lowers the corrosion rate, and enhances corrosion potentials. The impedance parameters exhibit analogous behavior, with the coating preventing water absorption and displaying corrosion resistance. The coating serves as a low-permeability barrier, exhibiting exceptional durability for naval steel over time, with an operational performance up to 98%. Full article

Free-standing copper oxide (Cu₂O)-copper hydroxide (Cu(OH)₂) nanocomposites with enhanced catalytic and antibacterial functionalities were synthesized on copper mesh using a green method based on spinach leaf extract and glycerol. EDX, SEM, and TEM analyses confirmed the chemical composition and morphology. The resulting Cu2O-Cu(OH)₂@Cu mesh exhibited notable hydrophobicity, achieving a contact angle of 137.5° ± 0.6, and demonstrated the ability to separate thick oils, such as HD-40 engine oil, from water with a 90% separation efficiency. Concurrently, its photocatalytic performance was evaluated by the degradation of methylene blue (MB) under a weak light intensity of 5 mW/cm², achieving 85.5% degradation within 30 min. Although its application as a functional membrane in water treatment may raise safety concerns, the mesh showed significant antibacterial activity against both Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria under both dark and light conditions. Using the disk diffusion method, strong bacterial inhibition was observed after 24 h of exposure in the dark. Upon visible light irradiation, bactericidal efficiency was further enhanced—by 17% for S. aureus and 2% for E. coli. These findings highlight the potential of the Cu₂O-Cu(OH)₂@Cu microfibers as a multifunctional membrane for industrial wastewater treatment, capable of simultaneously removing oil, degrading organic dyes, and inactivating pathogenic bacteria through photo-assisted processes. Full article

In this work, we present the development and validation of an automated system for the Successive Ionic Layer Adsorption and Reaction (SILAR) method, aimed at depositing Cu₂ZnSnS₄ (CZTS) thin films. The system is based on a Raspberry Pi Pico microcontroller programmed in Micro-Python (Thonny 4.0.2), allowing precise control over immersion sequences, timing intervals, and substrate positioning along two degrees of freedom. Automation enhances reproducibility, safety, and reduces human error compared with manual operation. CZTS films were deposited on borosilicate glass and optically and structurally characterized. A gradual darkening of the films with increasing deposition cycles indicates controlled material accumulation. X-ray diffraction (XRD) and Raman spectroscopy confirmed the presence of CZTS phases, although with a partially amorphous structure. The estimated optical bandgap of ~1.34 eV is consistent with photovoltaic applications. These results validate the functionality of the automated SILAR platform for repeatable and scalable thin-film fabrication, offering a low-cost alternative for producing semiconductor absorber layers in solar energy technologies. Full article

This study reports the synthesis, structural characterization, adsorption studies, nanoscale interaction, and photocatalytic application of pure and Fe-doped ZnS quantum dots for the degradation of the antibiotic cefalexin in aqueous solution. Nanoparticles were synthesized via the microwave-assisted method, and Fe doping was introduced at a 1% molar ratio. HRTEM images confirmed quasi-spherical morphology and high crystallinity, with particle sizes averaging 2.4 nm (pure) and 3.5 nm (doped). XRD analysis showed a consistent cubic ZnS structure. UV-vis spectra showed strong absorption at 316 nm for both samples, and PL measurements revealed emission quenching upon Fe doping. Photocatalytic tests under UV light demonstrated significantly higher degradation rates of 10 ppm cefalexin with Fe-doped ZnS, reaching near-complete removal within 90 min. Adsorption experiments revealed higher affinity and adsorption capacity of Fe-doped ZnS toward cefalexin compared to pure ZnS, as demonstrated by the Freundlich isotherm analyses, contributing significantly to enhanced photocatalytic degradation performance. High-resolution QTOF LC-MS analysis confirmed the breakdown of the β-lactam and thiazolidine rings of cefalexin and the formation of low-mass degradation products, including fragments at m/z 122.0371, 116.0937, and 318.2241. These findings provide strong evidence for the structural destruction of the antibiotic and validate the enhanced photocatalytic performance of Fe-doped ZnS. Full article

In the tumor microenvironment, M2 tumor-associated macrophages play a crucial role in promoting tumor growth, vascularization, and metastasis through their anti-inflammatory and tissue-repairing functions. To reprogram M2 cells into a more benign M1 phenotype and enhance the patient’s intrinsic immune response against cancer, siRNA and small molecules are used, which can be encapsulated into nanoparticles to enhance their stability, circulation time, and bioavailability. Albumin nanoparticles are ideal candidates for the delivery of such cargo because of their low toxicity, biocompatibility, biodegradability, prolonged circulation in the bloodstream, and feasible particle modification. In this study, we optimized a one-step desolvation method using the standard cross-linker glutaraldehyde and D-mannose as a second cross-linker for the synthesis of mannosylated albumin nanoparticles. The obtained nanoparticles demonstrated favorable physical characteristics, high encapsulation efficiency, and the most effective targeting into activated M2 macrophages overexpressing the mannose receptor in comparison to M1 macrophages and cancer cells in vitro. Full article

Quantum dots (QDs) are nanoparticles with intrinsic fluorescence. Recent studies have found that metal-based QDs often impart toxic effects on the biological systems they interact with. Their undefined limitations have offset their potential for biomedical application. Our study aimed to address the research gap regarding QDs’ impacts on the intracellular actin cytoskeleton and the associated structures. Our XTT viability assays revealed that QDs only reduced viability in transformed human liver epithelial (THLE-2) cells, whereas HeLa cells remained viable after QD treatment. We also used confocal microscopy to evaluate the morphological changes in THLE-2 induced by QDs. We further investigated cell protrusion morphology using phalloidin-Alexa488 which selectively labels F-actin. The fluorescent microscopy of this phalloidin label revealed that QD treatment resulted in the redistribution of actin filaments within both THLE-2 and HeLa cells. We also report that the average number of focal adhesions decreased in QD-treated cells. As actin filaments at the cell are peripherally linked to the extracellular matrix via talin and integrin and are thus a crucial component of cell motility, we conducted a migration assay. The migration assay revealed that cell motility was significantly reduced in both THLE-2 and HeLa cells following QD treatment. Our findings establish that the internalization of QDs reduces cell motility by rearranging actin filaments. Full article

The greenhouse effect, responsible for trapping heat in Earth’s atmosphere, has a parallel thermal phenomenon at the indoor scale known as the Room-Level Greenhouse Effect (RGHE), where solar radiation elevates room temperatures and increases energy consumption. The RGHE contributes to indoor temperature increases of 4–10 °C and elevates energy demands by 15–30% in high solar exposure zones, the effect being even worse in tropical zones. To address this problem, an innovative analog microarchitecture is proposed for real-time RGHE detection by sensing the sunlight intensity radiation factor (SIR). A compact analog system is introduced, comprising three stages: a Sensing Circuit Stage (SCS) that isolates the dynamic sunlight signal f (r) from static room condition factors (RCFs), an Amplification Stage (AS) that shifts and boosts the signal, and a Stabilized Peak Detection Stage (SPDS) that captures the peak solar intensity. The microsystem was tested across fixed f (m) levels of 0.75 V, 1.0 V, and 1.5 V, and varying f (r) values of 3 mV, 4 mV, and 5 mV. It successfully detects peak voltages ranging from 1.69 V to 1.92 V, with stabilization achieved within 60 µs, enabling accurate detection of the f (r) signal. The proposed microarchitecture offers a scalable approach to localized thermal monitoring in smart building environments using fully analog circuitry, designed and simulated in Cadence Virtuoso using the TSMC 180 nm technology library. Full article

The dynamic relationship between microplastics (MPs) in the air and on the Earth’s surface involves both natural and anthropogenic forces. MPs are transported from the ocean to the air by bubble scavenging and sea spray formation and are released from land sources by air movements and human activities. Up to 8.6 megatons of MPs per year have been estimated to be in air above the oceans. They are distributed by wind, water and fomites and returned to the Earth’s surface via rainfall and passive deposition, but can escape to the stratosphere, where they may exist for months. Anthropogenic sprays, such as paints, agrochemicals, personal care and cosmetic products, and domestic and industrial procedures (e.g., air conditioning, vacuuming and washing, waste disposal, manufacture of plastic-containing objects) add directly to the airborne MP load, which is higher in internal than external air. Atmospheric MPs are less researched than those on land and in water, but, in spite of the major problem of a lack of standard methods for determining MP levels, the clothing industry is commonly considered the main contributor to the external air pool, while furnishing fabrics, artificial ventilation devices and the presence and movement of human beings are the main source of indoor MPs. The majority of airborne plastic particles are fibers and fragments; air currents enable them to reach remote environments, potentially traveling thousands of kilometers through the air, before being deposited in various forms of precipitation (rain, snow or “dust”). The increasing preoccupation of the populace and greater attention being paid to industrial ecology may help to reduce the concentration and spread of MPs and nanoparticles (plastic particles of less than 100 nm) from domestic and industrial activities in the future. Full article

Electromagnetic interference (EMI) shielding is critical for maintaining signal integrity in high-speed electronic packaging. However, conventional shielding approaches face limitations in process complexity and spatial efficiency. In this study, an EMI shielding film based on trimodal silver (Ag) ink and low-dielectric polyimide (PI) resin was developed and comprehensively evaluated. The fabricated film exhibited an average shielding effectiveness (SE) of −99.7 dB in the 6–18 GHz frequency range and demonstrated a 50% increase in electrical conductivity after lamination (from 0.752 × 10⁵ S/m to 1.13 × 10⁵ S/m). The horizontal thermal conductivity reached 34.614 W/m·K, which was 3.4 times higher than the vertical value (10.249 W/m·K). Signal integrity simulations showed significant reductions in near-end crosstalk (NEXT, 77.8%) and far-end crosstalk (FEXT, 65%). Moreover, cyclic bending tests confirmed excellent mechanical durability, with a normalized resistance change below 0.6 after 1000 cycles at a bending radius of 4 mm. Notably, the film enabled a 50% reduction in signal line spacing while maintaining signal integrity, even without strict compliance with the 3W Rule. These results demonstrate the potential of the proposed EMI shielding film as a high-performance solution for advanced packaging applications requiring high-frequency operation, thermal management, and mechanical flexibility. Full article

Microfluidic devices are tiny tools used to manipulate small volumes of liquids in various fields. However, these devices frequently require additional equipment to control fluid flow, increasing the cost and complexity of the systems and limiting their potential for widespread use in low-resource biomedical applications. Here, we present a cost-effective and simple fabrication method for PMMA microfluidic chips using laser cutting technology, along with a low-cost and open-source peristaltic pump constructed with common hardware. The pump, programmed with an Arduino microcontroller, offers precise flow control in microfluidic devices for small volume applications. The developed application for controlling the peristaltic pump is user-friendly and open source. The microfluidic chip and pump system was tested using Jurkat cells. The cells were cultured for 24 h in conventional cell culture and a microfluidic chip. The LDH assay indicated higher cell viability in the microfluidic chip (111.99 ± 7.79%) compared to conventional culture (100 ± 15.80%). Apoptosis assay indicated 76.1% live cells, 18.7% early apoptosis in microfluidic culture and 99.2% live cells, with 0.5% early apoptosis in conventional culture. The findings from the LDH and apoptosis analyses demonstrated an increase in both cell proliferation and cellular stress in the microfluidic system. Despite the increased stress, the majority of cells maintained membrane integrity and continued to proliferate. In conclusion, the chip fabrication method and the pump offer advantages, including design flexibility and precise flow rate control. This study promises solutions that can be tailored to specific needs for biomedical applications. Full article

Understanding the mechanical properties of three-dimensional (3D)-printed ceramics while keeping the parts intact is crucial for advancing their application in high-performance and biocompatible fields, such as biomedical and aerospace engineering. This study uses non-destructive nanoindentation techniques to investigate the mechanical performance of 3D-printed zirconia across pre-conditioned and sintered states. Vat photopolymerization-based additive manufacturing (AM) was employed to fabricate zirconia samples. The structural and mechanical properties of the printed zirconia samples were explored, focusing on hardness and elastic modulus variations influenced by printing orientation and post-processing conditions. Nanoindentation data, analyzed using the Oliver and Pharr method, provided insights into the elastic and plastic responses of the material, showing the highest hardness and elastic modulus in the 0° print orientation. The microstructural analysis, conducted via scanning electron microscopy (SEM), illustrated notable changes in grain size and porosity, emphasizing the influencing of the printing orientation and thermal treatment on material properties. This research uniquely investigates zirconia’s mechanical evolution at the nanoscale across different processing stages—pre-conditioned and sintered—using nanoindentation. Unlike prior studies, which have focused on bulk mechanical properties post-sintering, this work elucidates how nano-mechanical behavior develops throughout additive manufacturing, bridging critical knowledge gaps in material performance optimization. Full article

This study presents the development of a modified polyimide (MPI) with low dielectric properties and low-temperature curing capability for high-frequency flexible printed circuit boards (FPCBs). MPI was cured using dicumyl peroxide (DCP) at 80–140 °C through a radical process optimized via DSC analysis, while Fourier-transform infrared (FT-IR) confirmed the elimination of C=C bonds and the formation of imide structures. The MPI film exhibited low dielectric constants (D_k) of 1.759 at 20 GHz and 1.734 at 28 GHz, with ultra-low dissipation factors (D_f) of 0.00165 and 0.00157. High-frequency S-parameter evaluations showed an excellent performance, with S11 of −32.92 dB and S21 of approximately −1 dB. Mechanical reliability tests demonstrated a strong peel strength of 0.8–1.2 kgf/mm (IPC TM-650 2.4.8 standard) and stable electrical resistance during bending to ~6 mm radius, with full recovery after severe deformation. These results highlight MPI’s potential as a high-performance dielectric material for next-generation FPCBs, combining superior electrical performance, mechanical flexibility, and compatibility with low-temperature processing. Full article

Microneedles (MNs) have emerged as a promising tool for pain-free drug delivery, offering an alternative to traditional syringe-based methods. Among various types of MNs, dissolving microneedles fabricated from hyaluronic acid (HA) have gained attention due to their biocompatibility and ability to deliver drugs with minimal discomfort. However, conventional HA MN fabrication techniques often limit needle lengths to a few hundred micrometers, which is insufficient for deeper drug penetration. This study introduces a novel fabrication method using bidirectional drawing lithography to extend the length of HA-based MNs. By adjusting the viscosity of HA solutions and employing a controlled pulling process, we demonstrate the feasibility of producing MNs with lengths ranging from millimeters to micrometers. An average height of 15 mm and tip diameters of approximately 80 μm were successfully produced. This advancement enhances the potential of HA MNs for transdermal drug delivery and interstitial fluid sampling. Full article