Search Results (4,575)

Biosensors based on electrolyte-gated organic field-effect transistors (EGOFETs) have attracted considerable attention due to their advantages, including low cost, inherent signal amplification, and low-voltage operation. A critical step influencing sensing performance is the integration of specific receptors onto the device surface. Among various strategies, the covalent immobilization of biorecognition elements onto gold surfaces via thiol chemistry is one of the most widely used approaches. In this study, we report the optimization of a mixed self-assembled monolayer (SAM) composed of 11-mercaptoundecanoic acid (11-MUA) and 3-mercaptopropionic acid (3-MPA) for label-free detection of human IgG using EGOFETs. The quality of the SAM was systematically modulated by varying the total concentration from 10 to 400 mM and characterized using X-ray Photoelectron Spectroscopy (XPS), Electrochemical Impedance Spectroscopy (EIS), Cyclic Voltammetry (CV), and Atomic Force Microscopy (AFM). The results revealed that a concentration of 50 mM yielded a densely packed and well-ordered monolayer. After covalent immobilization of anti-IgG antibodies via 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride/N-hydroxysuccinimide (EDC/NHS) chemistry and subsequent blocking with ethanolamine and bovine serum albumin (BSA), the functionalized gate electrodes were integrated into poly(3-hexylthiophene) (P3HT)-based EGOFETs. Electrical measurements demonstrated that EGOFET biosensors functionalized with the 50 mM SAM achieved optimal sensing performance. The devices exhibited a highly linear response (R² = 0.998) over a wide concentration range from 1 fM to 10 nM, with a LOD of 2.82 fM, and showed excellent selectivity against non-target immunoglobulins A and M (IgA and IgM). This SAM concentration optimization strategy provides a versatile approach for engineering high-performance EGOFET biosensors, with potential applicability to a broad range of disease biomarkers. Full article

Indium Tin Oxide (ITO) is one of the most widely used ohmic materials for fabricating ohmic layers in thin-film solar cells. ITO thin layers have reached almost the maximum theoretical conductivity and the lowest practical resistivity. Along with indium’s toxic environmental impact and the high cost of materials, these are the reasons why new materials for efficient, cheaper thin-film transparent ohmic layers are being examined. One of those materials is copper-doped zinc oxide (ZnO:Cu). In this paper, we present a new approach to copper-doped zinc oxide fabrication methods, based on the modern authorial Physical Vapor Co-Deposition technique, which involves optimizing Cu concentration to fine-tune crystal structure, optical band gap, and electrical properties, creating n-type TCOs essential for efficient charge transport in next-generation thin films perovskite solar cells. Full article

Graphene oxide (GO)–lipid hybrid nanostructures represent a promising class of multifunctional platforms for drug delivery and fluorescence-guided cellular imaging. In this study, we developed a graphene oxide-supported lipid bilayer system composed of rhodamine-labeled phosphatidylcholine (POPC-Rhod) for the delivery of the repurposed antispasmodic drug alverine citrate (ALV) to neuroblastoma cells. The hybrid nanostructures were assembled using two drug-loading strategies and characterized by UV–Vis spectroscopy, fluorescence analysis, dynamic light scattering, and atomic force microscopy to evaluate molecular interactions, vesicle size distribution, and nanomechanical properties. In vitro studies were performed using human neuroblastoma SH-SY5Y cells and their retinoic acid-differentiated neuronal-like counterparts. Confocal microscopy confirmed efficient cellular uptake of the fluorescent lipid–graphene hybrids, while viability and mitochondrial reactive oxygen species assays revealed differentiation-dependent cellular responses. ALV-loaded hybrids induced cytotoxic effects in proliferating neuroblastoma cells, whereas differentiated neuron-like cells exhibited greater tolerance and, at moderate concentrations, preserved viability despite increased oxidative stress. These findings demonstrate that graphene oxide–lipid hybrids can act as fluorescence-traceable drug delivery platforms and highlight the potential of alverine as a candidate for repurposing in neural cancer models. The system presented here provides a proof-of-concept framework for the development of multifunctional nanocarriers integrating therapeutic delivery with imaging capabilities. Full article

Background/Objectives: Modern dentistry focuses on the ongoing development of digital alternative technologies and the study of the properties of these innovative materials is deemed essential. Therefore, the objectives of this study were to evaluate the optical and surface characteristics of six computer-aided design/Computer-Aided Manufacturing (CAD-CAM) dental materials, both subtractive and additive, in relation to in vitro degradation. Methods: CAD-CAM dental materials, subtractively processed (Vita Enamic, Cerasmart, Brilliant and Tetric) and additively manufactured (Saremco Crowntec and Voco C&B), were prepared to standard dimensions of 14 × 10 × 1 mm, with baseline measurements taken prior to, and after, the degradation procedures, consisting of immersion in an ADA-recommended staining broth, artificial aging (thermocycling), and the combined effects of staining and in vitro aging. Additionally, two different surface treatments were investigated (polished and glazed). Results: The poorest color stability was observed for Tetric glazed specimens (mean value 25.585) subjected to staining, while the best performance was recorded for Brilliant polished Control (average value of 0.781). The staining procedure produced the most pronounced color changes. Surface treatment did not significantly affect color stability, and surface roughness was not influenced by either the degradation method or the surface treatment (p > 0.05). Atomic Force Microscopy (AFM) evaluation revealed superior performance of the glazed surfaces, characterized by lower nanoroughness values compared with polished surfaces and a smoother surface appearance. Conclusions: The staining potential of staining broth was demonstrated in this study, with the highest values recorded after the staining procedures. In addition, the influence of artificial aging alone and artificial aging combined with staining was investigated, providing relevant results for a better clinical approach. Moreover, surface treatment demonstrated reliability and therefore clinical applicability. Full article

In this study, we investigate the impact of processing strategies on the nanoscale morphology and photophysical behavior of donor–acceptor thin films composed of the polymeric donor PBDTTTPD and the n-type acceptor PNDI(2HD)2T. The blend morphology and interfacial characteristics were systematically tuned using three distinct fabrication techniques: spin-coating, convective self-assembly, and space-confined solvent vapor annealing. Atomic force microscopy and photoluminescence spectroscopy were employed to elucidate structure–property correlations relevant to all-polymer optoelectronic systems. Films processed via convective self-assembly exhibited nanoscale features with extensive donor–acceptor intermixing, leading to the most efficient photoluminescence quenching of nearly 85%, indicative of enhanced exciton dissociation and charge transfer. In contrast, as-cast films displayed moderately mixed morphologies with approximately 81% quenching, serving as a reference state. The solvent vapor annealing method induced pronounced phase segregation and the formation of larger domains, resulting in reduced photoluminescence quenching efficiency of about 52%. These findings demonstrate that the nanoscale morphology, and consequently the photophysical response, of PBDTTTPD:PNDI(2HD)2T blends can be precisely tailored through processing, providing valuable design guidelines for all-polymer optoelectronic applications such as organic photovoltaics and field-effect transistors. Full article

This review surveys how nanoparticles and biomolecular nanosized structures interact with model membrane systems, and how these interfacial processes govern their performance in drug and gene delivery, antimicrobial strategies, biosensing, and nanotoxicology. The nanostructures covered include polymeric nanoparticles, lipid-based carriers, peptide nanostructures, dendrimers, and multifunctional hybrids. Model membranes span Langmuir monolayers, supported lipid bilayers, vesicles/liposomes across sizes, and emerging hybrid or asymmetric constructs that better approximate native complexity. Mechanistically, interactions follow recurrent routes—surface adsorption, bilayer insertion, pore formation, and lipid extraction/reorganization—regulated by particle size, morphology, charge, ligand architecture, and lipophilicity, in conjunction with membrane composition, phase state, curvature, and asymmetry. A multiscale toolkit links structure, mechanics, and dynamics: Langmuir troughs and Brewster Angle Microscopy map thermodynamics and mesoscale morphology; atomic force microscopy and quartz crystal microbalance with dissipation resolve nanoscale topography and viscoelasticity; fluorescence microscopy/spectroscopy reports on localization and packing; neutron and X-ray reflectometry quantify vertical structure; molecular dynamics provides atomistic pathways and design hypotheses. Historically, the field advanced from early monolayers and bilayers, through the fluid mosaic model, to raft microdomains and modern biomimetic systems, enabling increasingly realistic experiments. Key advances include cross-method integration linking experimental observations with image-based computational models; persistent debates concern the translation from simplified models to living membranes, the role of dynamic coronas, and scale/force-field limits in simulations. Future efforts should prioritize hybrid models incorporating proteins and asymmetric lipidomes, standardized reporting and reference systems, rigorous coupling of experiments with calibrated simulations and machine learning, and alignment with safety-by-design and regulatory expectations, thereby shifting interfacial measurements from descriptive observation to predictive design rules. Full article

This study investigates the electrostatic and electrochemical behavior of polyaniline (PANI) and its composite with amine-functionalized multi-walled carbon nanotubes (PANI/MWCNT–NH₂) to elucidate the mechanisms governing ammonia (NH₃) sensing. High-resolution atomic force microscopy (AFM) coupled with electrostatic force microscopy (EFM) demonstrates that pristine PANI forms granular macroaggregates with localized charge distribution, whereas MWCNT incorporation promotes worm-like percolative networks that enhance charge delocalization and conductivity. Electrochemical characterization by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) corroborates these nanoscale observations, revealing significantly improved interfacial electron transfer kinetics in the composite. Upon exposure to NH₃, pristine PANI undergoes rapid de-doping and nonlinear signal suppression, while the composite exhibits a more progressive electrochemical modulation. Overall, the results demonstrate that NH₃ sensing in PANI-based films is governed not solely by electroactive material content but by the interplay between nanoscale morphology, electrostatic heterogeneity, and charge transport topology. The nanotube-mediated formation of delocalized and percolative conductive pathways provides structural and electrochemical robustness, enabling tunable, high-sensitivity operation suitable for next-generation, low-power ammonia sensing platforms. Full article

The sol–gel method was employed to prepare organic–inorganic hybrid materials capable of accommodating large amounts of a sodium salt and a commercial ionic liquid. The resulting samples, obtained as thin and transparent films, were characterized using thermogravimetric analysis (TGA), X-ray diffraction (XRD) and atomic force microscopy (AFM). The samples exhibit thermal stability and are essentially amorphous, which encourages further investigation. Interest in sodium arises from the fundamental similarities between the electrochemistry of sodium and lithium batteries, as well as the analogous physicochemical properties shared by these two elements. Sodium-ion batteries have thus emerged as highly promising energy storage systems, particularly well-suited for stationary applications. Full article

In this study, Ti-Co-Ce getter films were deposited via magnetron sputtering to investigate their activation mechanism—the thermal removal of surface passivation layers to restore gas sorption capability. The morphology before and after film activation was characterized using scanning electron microscopy (SEM) and atomic force microscopy (AFM). The oxygen content on the film surface before and after activation was measured using an energy-dispersive X-ray spectrometer (EDS), and gas desorption during activation was monitored with a quadrupole mass spectrometer (QMS). The combined results confirmed the absence of O₂ desorption during activation, suggesting oxygen migration into the film bulk. Crucially, in situ X-ray photoelectron spectroscopy (XPS) combined with controlled Ar⁺ ion sputtering depth profiling (0–30 nm) was employed to directly probe the chemical-state evolution within the thin film before and after thermal activation at 400 °C, thereby providing direct evidence of the activation dynamics. The data reveal that within the 0–10 nm near-surface region, a strong oxygen chemical potential gradient drives rapid oxide reduction and inward migration of lattice oxygen. At depths of 20–30 nm, moderate reduction coupled with oxygen enrichment induces phase separation, while around 30 nm, a dynamic equilibrium between oxygen inflow and outflow is established. These findings provide a theoretical basis for optimizing activation processes and guiding the development of low-temperature getter materials. This work is particularly relevant for MEMS, vacuum electronics, and other applications with stringent thermal budgets, expanding the design possibilities for heat-sensitive device integration. Full article

Graphene incorporation into polymer fibers offers a strategy to tune nanoscale morphology while preserving mechanical conformity for flexible composite applications. Graphene-based dopants can enable modulation of polymer fiber structure; however, the relationship between graphene incorporation, fiber morphology, and mechanical flexibility must be evaluated. This study investigates the integration of graphene oxide (GO) and reduced graphene oxide (RGO) into fibrous materials to tailor the structural and surface characteristics by fabricating GO- and RGO-enhanced poly(vinylidene fluoride) (PVDF) fibers via a wet-spinning process and examining the tunability of their morphology and its influence on mechanical properties. The effect of graphene doping and reduction state on fiber architecture is explored using scanning electron microscopy (SEM), atomic force microscopy (AFM), and Brunauer–Emmett–Teller (BET) surface area analysis. Fourier transform infrared (FTIR) and Raman spectroscopy analyses confirmed the incorporation and reduction of graphene derivatives within the PVDF matrix while revealing corresponding changes in chemical functionality and the piezoelectric phase of PVDF. Mechanical flexibility is assessed through tensile testing, revealing increased stiffness with graphene addition, although maintaining sufficient structural integrity for wearable applications. These results collectively demonstrate that graphene doping provides a facile route to engineer composite fibers, enabling a balance between morphological complexity and mechanical compliancy, while establishing graphene-enhanced fibers as promising materials for flexible sensing systems and wearable smart textiles. Full article

Nitridation of different materials using ion implantation is of considerable interest for many applications. As electronic components, oxynitride (SiO_xN_y) layers exhibit beneficial properties such as precise compositional variability, refractive index tunability, oxidation resistance, and low mechanical stress. In the present study we investigate nanoscale SiO_xN_y synthesized using ion implantation methods. To introduce N⁺ ions into a shallow Si subsurface region, both conventional ion beam implantation and plasma immersion ion implantation with subsequent high-temperature treatment in dry O₂ are used. The optical and morphological properties and chemical bonding of formed SiO_xN_y layers were studied by applying spectroscopic ellipsometry in the range of VIS-Near IR (SE) and IR (IR-SE), Raman spectroscopy and Atomic Force Microscopy (AFM). Monte Carlo modeling of implant profiles contributed to understanding physical and chemical processes and predicted different influences of the incorporated N⁺ ions on the oxidation mechanism, confirmed by the thickness dependence of SiO_xN_y/Si layers obtained from the SE data analysis. IR-SE spectral analysis established the formation of Si-O, Si-N, Si-N-O and Si-Si chemical bonds in the grown layers. The occurrence of amorphization of the Si crystal lattice due to incorporation of high-energy N⁺ ions into the Si lattice is confirmed by the Raman and ellipsometry results. The free Si atoms can congregate, forming nanocrystalline clusters. AFM imaging revealed that both implantation methods left the surface of the resulting SiO_xN_y layers considerably smooth with similar roughness parameter values. The results of the studies imply that the technological approaches used allow the production of high-quality nanoscale silicon oxynitride films with appropriate tunable composition and properties for possible application in advanced electronic devices for nanoelectronics, optoelectronics and sensor applications. Full article

This study reports the fabrication of porous anodic aluminum oxide (AAO) on a 6xxx series aluminum alloy by a two-step anodization route and systematically examines how anodization parameters govern the resulting morphology and wetting behavior. AAO samples were prepared in two groups: in Group 1, the anodization voltage was varied between 20 and 60 V at a fixed time of 60 min; in Group 2, the anodization time was varied between 30 and 120 min at a fixed voltage of 30 V. All anodizations were carried out in 0.3 M oxalic acid at room temperature. The AAO structures were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), and contact angle measurements. The pore diameters and interpore distances were found to be 13.3–40.6 nm and 45.3–86.7 nm, respectively, in Group 1, and 19.1–23.6 nm and 41.0–44.4 nm in Group 2. Analysis of SEM images reveals that increasing the anodization voltage results in larger pore diameters, interpore spacings, and porosity, but a reduced pore density. In contrast, changes in anodization time at a fixed voltage have a more modest effect on pore geometry. The anodized surfaces exhibit a marked change in wettability, with the water contact angle increasing from ~45° for the non-anodized alloy to ~123° for the best-performing AAO surface, without any additional chemical modification. These results demonstrate that, even under simple room-temperature conditions, AAO morphology and hydrophobic behavior can be tuned in a predictable manner by appropriate choice of anodization parameters, which is relevant for the design of membranes, sensors, and functional surface coatings. Full article

Zirconia-based hybrid blends at various molecular or nanometer scales have attracted significant interest from a technological perspective. In particular, several inorganic-organic hybrids are being applied in the biomedical field. In this context, inorganic ZrO₂ and hybrids composed of ZrO₂, and polyethylene glycol (PEG) have been synthesized through the sol–gel process and characterized from both morphological and spectroscopic viewpoints to explore their potential as hybrid biomaterials. Atomic Force Microscopy (AFM) has enabled a quantitative assessment of the surface roughness of bioactive sol–gel-based materials. The findings indicated an increase in material porosity in relation to the amount of PEG present in the systems, underscoring the important role of PEG in influencing the morphological characteristics of zirconia-based blends. AFM images display the typical globular structure of PEG spread across the surface of all systems. All hybrid systems seem to be uniform, and no phase separation is evident, thereby validating that the produced materials are hybrid nanostructured ones. The simultaneous presence of both inorganic and organic phases was verified using Fourier-transform infrared spectroscopy (FT-IR). FT-IR deconvolution in 850–550 cm⁻¹ region showed that PEG progressively perturbs the Zr–O–Zr network, increasing disorder and establishing more flexible inorganic domains at high PEG content. Increasing polymer amount enhanced cell viability against NIH-3T3 cell line, while antibacterial activity decreased, with pure ZrO₂ showing the strongest inhibition against Escherichia coli (E. coli). Full article

Cu₂ZnSn(S,Se)₄ (CZTSSe) is a candidate thin-film photovoltaic material; however, its performance is restricted by innate defect-induced nonradiative recombination. Low-concentration Ge doping has been identified as an efficient way to mitigate these defects, but the selenization temperature remains an important process parameter that governs the structure and optoelectronic characteristics of CZTSSe absorbers. In the present work, low-concentration Ge-doped Cu₂ZnSn_0.95Ge_0.05S₄ (CZTGS) precursor films were synthesized through a green, n-butylammonium butyrate-based solution approach. The effects of the selenization temperature (530–570 °C) on the microstructure, composition, and photovoltaic performance of Cu₂ZnSn_0.95Ge_0.05(S,Se)₄ (CZTGSSe) films and devices were comprehensively investigated. X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), energy-dispersive X-ray spectrometer (EDS), atomic force microscopy (AFM) were performed to comprehensively characterize the synthesized samples, and the results suggested that the selenization temperature dramatically altered the film grain growth, crystallinity, elemental retention and surface roughness. Specifically, the film that underwent selenization at 550 °C presented the best crystallinity, which was accompanied by large-scale even grains, efficient Ge⁴⁺ addition to the kesterite lattice and the lowest surface roughness. These better properties in terms of structure and composition resulted in the lowest carrier transport resistance (R_s = 8.6 Ω∙cm²), improved recombination resistance (R_j = 5.9 kΩ∙cm²), inhibited nonradiative recombination, and prolonged carrier lifetime (τ_EIS = 35.8 μs). Therefore, the resulting CZTGSSe thin-film solar cell had an 8.69% better power conversion efficiency (PCE), while its open-circuit voltage (V_OC) was 0.42 V, the fill factor (FF) was 55.51%, and the short-circuit current density (J_SC) was 37.71 mA·cm⁻². Our results elucidate the mechanism by which the selenization temperature regulates low-concentration Ge-doped kesterite devices and provide more insights into the optimization of processes for cost-effective, high-performance, and green thin-film solar cells. Full article

This work focuses on the study of tribo-mechanical and microstructural properties of TiCN/ZrCN multilayer coatings with a modulation period of 12 nm, obtained by a conventional cathodic arc technique. The coatings were deposited at a temperature of 320 °C using nitrogen and methane reactive gases (N₂/CH₄) mixture in three different proportions. Surface morphology, composition, hardness, adhesion, friction and wear behavior were studied using atomic force microscopy, scanning electron microscopy with energy dispersive spectroscopy, X-ray diffraction, Raman spectroscopy, nanoindentation, and scratch and wear tests. The analysis of the coating composition revealed a strict dependence of the carbon content on the CH₄ flow rate. It was found that the coatings with a carbon content of 14.6 at.% and 15.9 at.% consist of crystalline TiZr (C,N) with the presence of amorphous carbon. All the studied TiCN/ZrCN coatings showed improved tribo-mechanical properties compared to TiN/ZrN multilayers obtained under the same deposition conditions. The highest hardness of 40 GPa was obtained for the coating deposited at a N₂/CH₄ flow rate of 370/100 sccm. The lowest wear rate of 3.16 × 10⁻⁶ mm³/N·m under dry sliding conditions was observed in the multilayer coatings deposited at the N₂/CH₄ flow rates of 330/140 sccm. Full article