Search Results (411)

Developing an ultrasensitive electrochemiluminescence (ECL) detection platform remains challenging due to the limited enrichment efficiency of ECL emitters and co-reactants at the electrode interface, as well as the insufficient catalytic enhancement of co-reactant conversion. Moreover, simultaneous in situ analyte enrichment and efficient anti-interference capability are often difficult to achieve in a single sensing interface. Herein, a new ECL platform was developed based on nanocatalyst-supported nanochannel-confined surfactant micelle (SM) system, which integrates an enhanced luminol-dissolved oxygen (DO) ECL response for the ultrasensitive detection of antibiotic rifampicin (RIF). A nanocomposite comprising nitrogen-doped graphene quantum dots and a molybdenum disulfide nanosheet (NGQDs@MoS₂) was modified on an indium tin oxide (ITO) electrode. This nanocomposite layer catalyzed the oxygen reduction reaction (ORR), boosting the co-reactant efficiency of DO. Vertically ordered mesoporous silica film filled with surfactant micelles (SM@VMSF) was subsequently grown in situ on the NGQDs@MoS₂ surface. The hydrophobic micelles enable the simultaneous enrichment of luminol, DO, and RIF. Integrating the triple-enrichment effect of surfactant micelles with the high electrocatalytic effect of NGQDs@MoS₂ nanocomposite results in significant ECL enhancement of the luminol–DO. SM@VMSF also provides an excellent molecular sieving effect, endowing the sensor with high anti-interference capability and stability. RIF quenches the ECL signal by consuming superoxide anion radicals, enabling sensitive detection. Detection of RIF was established with a high sensitivity (2927 a.u. per nM) wide linear range (10 pM to 10 μM) and a low limit of detection (LOD, 2.5 pM). The fabricated sensor exhibits good selectivity and high fabrication reproducibility (relative standard deviation, RSD, of 1.9%). Additionally, the determination of RIF in eye drops and seawater samples was realized. This work offers new insights for the design of high-performance ECL sensing interfaces and sensitive detection of RIF. Full article

We report the fabrication and electrochemical characterization of TiO₂-based impedimetric sensors for the analysis of artificial sweat compositions. Two-electrode topologies were patterned on indium tin oxide (ITO) substrates: an interdigitated electrode (IDE) configuration and a Hilbert fractal electrode (HFE) geometry. TiO₂ thin films with thickness up to 350 nm were deposited by dip-coating and evaluated as photoactive sensing layers. The impedimetric response of the sensors was investigated by electrochemical impedance spectroscopy in artificial sweat with composition varied in terms of ionic content (0–100 mM Na⁺) and organic content (2.5–30 mM lactic acid and 5–50 mM urea). Regardless of TiO₂ thickness, the high-frequency response is predominantly governed by electrode topology, with the HFE design exhibiting up to 2.5-fold higher modulation compared to the IDE configuration. Under UV illumination, a low-frequency, photo-assisted response emerges, influenced by the TiO₂ layer thickness and primarily sensitive to the organic components of the solution, particularly lactic acid. These results suggest that frequency-resolved impedance measurements in TiO₂|ITO structures may enable partial differentiation between ionic conductivity and organic contributions in sweat, providing a promising basis for multi-parameter sweat analysis. Full article

In this paper, a study on the development of indium-doped Cu_xS heterojunction-based conductometry sensors is presented. To fabricate the sensors, thick films of In-Cu_xS heterojunctions were sprayed directly on the alumina sensing platform provided with interdigitated Pt electrodes. The effect of the doping level with different nominal amounts of InCl₃ additive (0%, 3%, and 5%) on the structural, morphological and optical properties of Cu_xS films was first studied by XRD, AFM, UV-Vis and Raman spectroscopy. Moreover, the electrical and sensing characteristics towards low concentrations of hydrogen sulfide (H₂S) in air were investigated. The tests carried out clearly demonstrated the positive effect of In doping on the H₂S sensing performance of Cu_xS. The 5%-doped Cu_xS sensor showed the highest sensitivity to the target gas compared to the other sensor, as well as good stability and selectivity properties. Full article

In this study, reactive radio frequency magnetron sputtering was used to deposit thin films. Gadolinium oxide was deposited on titanium nitride substrates at different deposition times and oxygen concentrations. Next, rapid thermal annealing and supercritical fluid treatment were performed. The three-dimensional profiler (alpha-step), X-ray diffractometer, and X-ray photoelectron spectroscopy were used to measure the thickness, surface morphology, crystal structure, and element analysis. Then, indium tin oxide was sputtered and deposited on the gadolinium oxide, which was covered with the metal mask to form a top electrode, thereby manufacturing a metal/insulator/metal resistive memory structure. Finally, a power meter was used to measure the characteristics of the resistive random access memory, including the current–voltage characteristics, and to explore the leakage current conduction mechanism and component durability. Full article

The blood-brain barrier (BBB) is one of the most selective physiological interfaces in the human body. Transendothelial electrical resistance (TEER) has become a widely adopted quantitative metric for assessing its in vitro structural and functional integrity. Although TEER measurements are routinely incorporated into BBB-on-chips, the absence of harmonized electrode architectures, measurement settings, and reporting standards continues to undermine reproducibility and translational reliability among laboratories. This systematic review provides the first comprehensive classification and critical comparison of electrode configurations used for TEER assessment, specifically within BBB-on-chip systems. Eligible studies were analyzed and categorized according to electrode design, fabrication method, integration strategy, and operational constraints. We critically evaluated six principal electrode architectures, highlighting their performance trade-offs in terms of uniformity of current distribution, long-term stability, scalability, and compatibility with dynamic shear conditions. Furthermore, we propose a bioinspired TEER reporting framework that consolidates essential metadata, including electrode specification, temperature control, viscosity effects, and blank resistance correction. Our analysis proposes screen-printed and hybrid silver-indium tin oxide (ITO) electrodes as promising candidates for next-generation BBB platforms. Moreover, our review provides a structured roadmap for standardizing TEER electrode design and reporting practices to facilitate interlaboratory consistency and accelerate the adoption of BBB-on-chip systems as truly biomimetic platforms for predictive neuropharmacological workflows. Full article

Conductive polymers (CPs), such as polypyrrole (PPy), have shown promising properties for use as electro-responsive bioactive scaffolds for tissue regeneration. PPy can be synthesized by chemical electrosynthesis and doped with biomolecules such as hyaluronic acid (HA). Taking advantage of the electrochemical synthesis versatility, nanofibers for surface-modified indium tin oxide (ITO) electrodes can be used as templates to produce tridimensional HA-doped PPy scaffolds. In this study, polyvinyl alcohol/chitosan (PVA/CTS) electrospun nanofibers deposited on ITO electrodes were used as a 3D template for the in situ electrosynthesis of HA-doped PPy to produce a bioactive scaffold for tissue engineering. The final material gathers the advantages of each biopolymer, the porous morphology of the nanofiber, and the conductivity of the electrosynthetized polymer. Furthermore, the biological activity of the NF-PVA/CTS@PPy:HA composite was evaluated in NIH-3T3 fibroblasts by MTT, resulting in a cell viability of 146 ± 40% and wound-healing capacity of 97 ± 1.9% at 24 h of culture. Full article

Transparent conductive oxides (TCOs), such as indium tin oxide (ITO), are essential for flexible electronics; however, conventional vacuum-based deposition is costly and thermally aggressive for polymers. This study investigated the surface functionalization of PET substrates with ITO thin film-based forced hydrolysis as a low-cost, reproducible alternative. $\mathrm{S}\mathrm{n}{\mathrm{O}}_2$ nanoparticles were synthesized by forced hydrolysis at 180 °C for 3 h and 6 h, yielding crystalline nanoparticles with a cassiterite phase and an average crystallite size of 20.34 nm. The process showed high reproducibility, enabling consistent structural properties without complex equipment or high-temperature treatments. The $\mathrm{S}\mathrm{n}{\mathrm{O}}_2$ sample obtained at 3 h was incorporated into commercial ${\mathrm{I}\mathrm{n}}_2{\mathrm{O}}_3$ to form a mixed In–Sn–O oxide, which was subsequently deposited onto PET substrates by spin coating onto UV-activated PET. The resulting 1.1 µm ITO films demonstrated good adhesion (4B according to ASTM D3359), a low resistivity of 1.27 × 10⁻⁶ Ω·m, and an average optical transmittance of 80% in the visible range. Although their resistivity is higher than vacuum-processed films, this route provides a superior balance of mechanical robustness, featuring a hardness of (H) of 3.8 GPa and an elastic modulus (E) of 110 GPa. These results highlight forced hydrolysis as a reproducible route for producing ITO/PET thin films. The thickness was strategically optimized to act as a structural buffer, preventing crack propagation during bending. Forced hydrolysis-driven PET sheet functionalization is an effective route for producing durable ITO/PET electrodes that are suitable for flexible sensors and solar cells. Full article

This work presents the design of a novel electrochemical sensor for highly sensitive determination of LEV, utilizing a sensing platform based on a newly synthesized, high-purity manganese (III) porphyrin complex [5,10,15,20-tetrayltetrakis(2-methoxybenzene-4,1-diyl) tetraisonicotinateporphyrinato] manganese (III) porphyrin (MnTMIPP). The successful synthesis of the MnTMIPP complex was verified using ultraviolet–visible (UV–Vis) and infrared spectroscopy (IR). The sensing electrode was fabricated by depositing the synthesized material onto an indium tin oxide (ITO) electrode via a drop-coating method. Under optimized experimental conditions, the proposed sensor demonstrated a wide dynamic range, from 10⁻⁹ M to 10⁻³ M, with a low calculated detection limit of 4.82 × 10⁻¹⁰ M. Furthermore, the MnTMIPP/ITO electrode displayed interesting metrological performance: high selectivity, reproducibility, and stability. Successful application in spiked river water and saliva samples with satisfactory recovery rates confirms the sensor’s potential as a reliable and cost-effective platform for monitoring LEV in real-world environments. Full article

Transparent conductive films based on silver nanowire meshes have demonstrated significant potential as alternatives to conventional tin-doped indium oxide and fluorine-doped tin oxide thin films. However, these materials feature high junction resistance, poor damp heat (DH) stability, and weak mechanical adhesion to substrates, which are critical issues that must be addressed before any practical applications. In this paper, transparent conducting films composed of silver nanowire (AgNW) frameworks and amorphous indium zinc oxide (IZO) fillers were prepared by a spin-coating method. The AgNW-IZO composite films exhibited a higher conductivity and better DH stability and adhesion to substrates than that of their constituent parts alone. The lowest sheet resistance of the composite films was 3.3 ohm/sq with approximately 70% transparency in the visible spectrum. No degradation was observed after 8 months. The excellent DH stability and mechanical adhesion might facilitate applications of these AgNW-IZO composite films in optoelectronic devices. Furthermore, the composite electrode is shown to have potential as a transparent heater. Full article

Tungsten oxide (WO₃) nanostructures have emerged as promising electroactive materials due to their high pseudocapacitance, structural versatility, and chemical stability, while reduced graphene oxide (rGO) provides excellent electrical conductivity and surface area. The strategic combination of these nanomaterials in hybrid electrodes has gained attention for enhancing the energy storage performance of supercapacitors. In this work, we report the fabrication and electrochemical performance of nanostructured multilayer films based on the electrostatic Layer-by-Layer (LbL) self-assembly of poly (amidoamine) (PAMAM) dendrimers alternated with tungsten oxide (WO₃) nanofibers dispersed in reduced graphene oxide (rGO). The films were deposited onto indium tin oxide (ITO) substrates and subsequently subjected to electrochemical reduction. UV-Vis spectroscopy confirmed the linear growth of the multilayers, while atomic force microscopy (AFM) revealed homogeneous surface morphology and thickness control. Electrochemical characterization by cyclic voltammetry (CV) and galvanostatic charge–discharge (GCD) revealed a predominantly electrical double-layer capacitive (EDLC) behavior. From the GCD measurements (PAMAM/rGO-WO₃)₂₀ films achieved an areal capacitance of ≈2.20 mF·cm⁻², delivering an areal energy density of ≈0.17 µWh·cm⁻² and an areal power density of ≈2.10 µW·cm⁻², demonstrating efficient charge storage in an ultrathin electrode architecture. These results show that the synergistic integration of PAMAM dendrimers, reduced graphene oxide, and WO₃ nanofibers yields a promising strategy for designing high-performance electrode materials for next-generation supercapacitors. Full article

Dielectric/Ag/dielectric (DAD) multilayer thin-film transparent electrode features high visible-light transmittance, low sheet resistance, good mechanical flexibility, and low haze. The fabrication techniques are compatible with large-scale integrated circuits, and the materials are cheap. These advantages make the DAD transparent electrodes a promising alternative to indium tin oxide (ITO) electrodes for flexible devices. This review summarizes recent advances in DAD transparent electrodes on flexible substrates, mainly focusing on the opto-electrical performance improvement due to damping of the localized surface resonance (LSPR) of Ag nanoparticles (AgNPs). It begins with an analysis of the performance-limiting factors of DAD transparent electrodes, elucidating the importance of damping the LSPR of AgNPs. Subsequently, the state-of-the-art fabrication methods for Ag ultrathin films of weak LSPR and the dielectric material optimization are reviewed. It concludes with perspectives on future research. Full article

Addressing the urgent need for low-temperature processes in the manufacturing of flexible vehicle-mounted touch display devices, this study investigates the process–structure–performance relationships of indium tin oxide (ITO) thin films prepared by DC magnetron sputtering on transparent polyimide (CPI) substrates. A synergistic strategy of “low-temperature deposition (110 °C)–230 °C atmospheric annealing” was employed. The optimal sample exhibited excellent comprehensive performance: a resistivity as low as 203 μΩ·cm, an average visible light transmittance of 89.2%, a surface roughness of 0.76 nm, and the ability to endure 100,000 bending cycles at a radius of R = 5 mm with a sheet resistance change rate of less than 10%. Microstructural and chemical state analyses revealed that this process facilitates the complete oxidation of Sn²⁺ to Sn⁴⁺ (Sn⁴⁺/Sn²⁺ ratio of 8.2:1) and the controlled formation of oxygen vacancies (O_L/O_V ratio of 6.5:1), leading to a synergistic improvement in carrier concentration (8.7 × 10²⁰ cm⁻³) and mobility (35.2 cm²/V·s). This work elucidates the crystallization kinetics and doping mechanisms under low-temperature conditions, providing a viable low-temperature technical pathway for the fabrication of high-performance transparent electrodes in flexible electronics. Full article

Roll-to-roll production of thin organic and large-area electronic (TOLAE) devices often involves a two-step process per functional layer: a continuous, un-pattered deposition of the film and subsequent structuring process, such as laser ablation. Thin-film organic devices should be protected using ultra-barrier films. To perform laser ablation of functional layers on top of such barrier films, in particular that of transparent electrodes, highly selective laser ablation is required to completely remove the layers without damaging the thin-film barrier layers underneath. When targeting highly selective laser ablation of indium tin oxide (ITO) on top of silicon nitride (SiN) barrier layers with a 1064 nm picosecond or 1030 nm femtosecond laser, we observed the emergence of visible large-scale patterns due to local variations in ablation quality. Our investigations using a very sensitive Raman spectroscopy setup show that the observed ablation variations stem from subtle differences in optical path length within the heat-stabilized plastic substrates. These variations are likely caused by minute, localized changes in the refractive index, introduced during the bi-axial stretching process used in film fabrication. Depending on the optical path length, these variations lead to either constructive or destructive interference between the incoming laser beam and the light reflected from the back surface of the substrate. By performing laser ablation under an angle such that the reflected and incoming laser beam do not spatially overlap, highly selective uniform laser ablation can be performed, even for two stacked optically transparent layers. Full article

This study aims to propose a plausible application of a novel electrochemical biosensing system for detecting antibodies against SARS-CoV-2 (anti-rS) in serum samples. The uniqueness of this study lies in the biosensor utilizing recombinant spike glycoprotein (SCoV2-rS) immobilized on an indium tin oxide (ITO) electrode modified with (3-aminopropyl)triethoxysilane (APTES). The electrochemical performance was evaluated using square wave voltammetry (SWV), demonstrating a linear relationship between the current density and anti-rS concentration. The limit of detection (LOD) was found to be 113 ng/mL (0.75 nM), and the limit of quantitation (LOQ) was equal to 338 ng/mL (2.25 nM). The reported electrochemical biosensor offers a straightforward and efficient method for evaluating the immune status of individuals who have recovered from COVID-19 and been vaccinated against this virus without the need for any redox probe. Full article

Visual impairments pose a significant global health challenge, and visual electrophysiological (EP) acquisition plays a pivotal role in diagnosing ophthalmic diseases. However, traditional electrodes still encounter limitations such as inadequate mechanical adaptability and reusability. This study proposes a stretchable and transparent electrode (STE) consisting of a conductive paste/indium tin oxide layer on a polymethyl methacrylate substrate. Leveraging an island–bridge design, the STE renders reliable performance even after being subjected to 1000 cycles of 25% lateral strain and 18% diagonal strain, exhibiting exceptional mechanical flexibility and realizing seamless attachment to soft tissue. Furthermore, optimized conductive paste layer thickness yields a signal-to-noise ratio comparable to commercial electrodes, achieving equivalent performance to Ag/AgCl electrodes in electroretinogram (ERG), electrooculography (EOG), and visual evoked potential (VEP) acquisition. The STE’s mechanical suitability and inconspicuous features hold significant potential for widespread clinical adoption in ophthalmic diagnostics and personalized eye healthcare, offering improved comfort, reusability, and diagnostic precision. Full article