Search Results (165)

High-entropy alloys (HEAs), composed of five or more principal elements in near-equimolar ratios, have emerged as a groundbreaking class of materials for next-generation flexible electronics. This review systematically examines the unique potential of HEAs as sensing materials, moving beyond their traditional role as structural components. We first elucidate the fundamental mechanisms—core effects including lattice distortion, sluggish diffusion, and the cocktail effect—that endow HEAs with an exceptional synergy of high strength, good ductility, tunable electrical resistivity, and superior electrocatalytic activity. Subsequently, we critically analyze the state-of-the-art strategies for processing HEA-based micro/nano structures, including mechanical alloying, wet-chemical synthesis, and non-equilibrium deposition techniques, with an emphasis on their compatibility with flexible substrates. The core of the review categorizes and discusses the latest advances in HEA-based flexible sensors for strain/stress, gas, and electrochemical (e.g., glucose, biomarkers, heavy metals) detection, highlighting the structure–property–performance relationships. Representative studies have demonstrated that HEA flexible strain sensors achieve a temperature coefficient of resistance as low as 45.59 ppm/K with no signal drift over 6000 stretching cycles; room-temperature hydrogen sensors reach a detection limit down to 31 ppb with a response time of 19 s; and non-enzymatic glucose sensors deliver a sensitivity up to 3043 μA·mM⁻¹·cm⁻². Finally, we summarize the key challenges—such as manufacturing scalability, long-term stability under dynamic deformation, and cost-effectiveness—and provide a forward-looking perspective on promising research directions, including high-throughput compositional screening, multi-functional sensor arrays, and the integration of machine learning for rational material design. Full article

Accurate quantification of glucose is vital for quality control in the food industry. While earth-abundant Cu has emerged as a promising candidate for non-enzymatic electrochemical sensing, conventional electrode fabrication relying on powder coating with polymeric binders inevitably buries active catalytic sites and impedes both electron transfer and mass transport. In this study, a binder-free, self-supporting Cu nanoparticles/Ni foam (Cu NPs/NF) electrode was developed via a facile one-step hydrothermal method. Benefitting from the enhanced charge-transfer efficiency and a substantially enlarged electrochemical active surface area, the Cu NPs/NF-based electrochemical glucose sensor exhibited a wide linear detection range (0.25–3310.52 μM), a high sensitivity of 7000 μA mM⁻¹ cm⁻², a low detection limit of 0.32 μM, and a rapid response time of 3 s. Furthermore, the developed Cu NPs/NF electrode displayed favorable reproducibility, storage stability, and high selectivity against common interferents present in food matrices, demonstrating its reliability for practical applications. The feasibility of the proposed sensor was successfully validated in real beverage samples. Given the simplicity of the one-step hydrothermal synthesis and the portability afforded by the self-supporting electrode architecture, this Cu NPs/NF electrode emerges as a highly attractive candidate for commercial glucose sensors. Beyond glucose, the design strategy can be readily extended to the detection of other electroactive food-quality markers, enabling the broader applicability of this electrode platform in comprehensive food analysis. Full article

The development of non-enzymatic glucose sensors for beverage analysis remains challenging due to insufficient active sites, poor conductivity, and limited stability in complex matrices. A nickel-carbon nanotube composite (Ni/CNT−600) was synthesized via in situ solvothermal deposition followed by pyrolysis at 600 °C under an inert atmosphere. The optimized Ni/CNT−600 featured uniform anchoring of Ni nanoparticles on CNTs through strong Ni–C and Ni–O–C interfacial bonds, validated by various characteristic techniques. The Ni/CNT−600 sensor exhibited exceptional sensitivity (538.48 μA mM⁻¹ cm⁻²) and an ultralow detection limit (0.003 μM) in 0.1 M NaOH at +0.65 V, surpassing many reported metal-based and enzymatic sensors. It demonstrated remarkable selectivity against key interferents (e.g., ascorbic acid, uric acid). In real beverage samples (orange juice, grape juice, cola, green tea, milk), recovery rates ranged from 95.6% to 112.8%. This work demonstrates a well-defined Ni-CNT synergistic interface that contributes to enhanced non-enzymatic glucose sensing performance, effectively addressing matrix complexity in beverages. Full article

As a promising class of catalysts for enzymatic glucose sensors, Prussian blue analogues (PBAs) exhibit exceptional biomimetic activity. However, their performance is often constrained by poor intrinsic conductivity, which typically limits their sensitivity. To address this limitation, this study presents an effective approach using direct in situ growth of PBAs on the electrode substrates, which enables the effective integration of PBA-based electrochemical systems. A porous Ni framework was first electrodeposited onto a screen-printed gold electrode substrate, followed by the reduction of Pt onto the porous Ni. Subsequently, NiFe PBA was synthesized in situ using the porous Pt/Ni structure as a sacrificial template. Functionalized with glucose oxidase (GO_x), the PBA/Pt/Ni biosensor exhibited excellent performance for glucose detection in buffer solution, with a high sensitivity of 262.6 μA mM⁻¹·cm⁻² and an ultra-low detection limit of 1.45 μM (calculated at a signal-to-noise ratio of 3, S/N = 3). Notably, its sensitivity corresponds to a two-fold enhancement relative to the electrodes modified with commercial Prussian blue using the conventional drop-casting method. Even when tested in human sweat samples, the biosensor achieved a high sensitivity of 236.4 μA mM⁻¹·cm⁻² and a linear detection range of 20–1000 μM, with the broad sensing range fully encompassing the typical physiological concentrations of glucose in human sweat. This excellent performance arises from the high specific surface area of the porous Pt/Ni structure and the tight connection between PBA and the sacrificial Ni anode. This research presents a promising design strategy for advanced, wearable, and non-invasive health-monitoring platforms. Full article

Portable non-enzymatic electrochemical glucose sensors offer potential for decentralized healthcare and medical education; however, their integration into simulation-based teleconsultation training workflows remains limited. This study presents the functional integration of a portable copper-modified electrochemical glucose sensor into a web- and Android-based telemedicine platform within a simulation-based medical education framework. Screen-printed carbon electrodes were electrochemically activated and modified via copper electrodeposition. Surface and electrochemical characterization were performed using SEM-EDX and cyclic voltammetry, respectively, followed by chronoamperometry for quantitative detection. Glucose solutions in PBS (pH 10) were measured using 70 µL samples, and the resulting signals were converted into glucose values (mg/dL) through a calibration model and incorporated into simulated gynecological teleconsultation workflows. The sensor exhibited a stable amperometric response at +0.60 V, with a linear range of 3.125–50 mM (R² = 0.9822), an area-normalized sensitivity of 0.061 µA·mM⁻¹·cm⁻², and a limit of detection of 1.39 mM. Implementation within the simulation scenario (n = 26) demonstrated 69% high/very high perceived usability and 88% high/very high educational value. These results support the feasibility of functionally integrating portable electrochemical sensing into simulation-based teleconsultation training and provide a proof-of-concept framework for future technical refinement and broader educational validation. Full article

Rapid and accurate urea detection is of considerable importance in environmental monitoring and biomedical analysis, as abnormal urea levels are associated with water contamination and various health conditions. In this study, a silver nanoparticle-decorated graphene oxide (Ag/GO) composite was synthesized via a simple chemical reduction method. The characterization results confirmed the successful formation of well-crystalline Ag nanoparticles (7.44 ± 1.46 nm) with uniform dispersion on GO, with a Ag loading of 39.1 wt%. The electrochemical performance for urea detection was evaluated in an alkaline medium (0.1 M NaOH) using cyclic voltammetry and chronoamperometry in a three-electrode system. The Ag/GO-modified glassy carbon electrode exhibited a strong electrocatalytic response toward urea oxidation, with a linear detection range of 1–10 mM. The sensitivity and limit of detection (LOD) were 36.8 μA mM⁻¹ and 0.11 mM, respectively. The sensor also demonstrated excellent selectivity in the presence of common interfering species, including uric acid, ascorbic acid, and glucose, along with good reproducibility, repeatability, and stability. Furthermore, the practical applicability of the sensor was assessed in real samples, where satisfactory recovery was achieved in tap water, while reduced performance was observed in milk due to matrix effects. These findings indicate that the Ag/GO composite can serve as an effective alternative electrode material for non-enzymatic electrochemical detection of urea, particularly in wastewater and biological systems. Full article

Two-dimensional Ti₃C₂O₂ MXene has emerged as a promising electrode material for non-enzymatic glucose sensing due to its metallic conductivity and biocompatibility. However, the atomic-scale sensing mechanism remains unclear. This DFT study uses the PBE functional with the D3(BJ) dispersion correction to elucidate glucose–MXene interactions under idealized vacuum conditions. Pristine Ti₃C₂O₂ shows metallic behavior with a density of states of about 8.2 states per electron volt at the Fermi level, dominated by Ti 3d states. β-d-glucose adsorbs onto the surface through hydrogen bonding, with an adsorption energy of −0.82 eV at a separation distance of 2.8 angstroms. Bader analysis indicates a transfer of about 0.15 electrons from MXene to glucose, resulting in a Fermi level shift of about −0.15 eV and an 18% reduction in the density of states at the Fermi level. These changes correspond to an estimated sensitivity of approximately 0.6 μA mM⁻¹ cm⁻² and a detection limit of about 17 µM, consistent with reported experimental performance of MXene-based sensors. Comparative adsorption calculations for common sweat interferents yield −0.45 eV for lactate and −0.25 eV for urea, indicating weaker interfacial affinity than glucose; these values reflect thermodynamic binding strength and possible surface occupation rather than definitive electrochemical selectivity, which additionally depends on redox potential, electron-transfer kinetics, and operating bias. We acknowledge three main limitations: first, the model considers only pure oxygen termination rather than mixed oxygen, hydroxyl, and fluorine terminations; second, the calculations are performed under vacuum rather than in aqueous conditions; third, the study is based on static zero kelvin structures rather than finite temperature dynamics. Despite these idealizations, the results provide baseline mechanistic insights to support rational design of MXene-based glucose sensors. Full article

Fresh figs are characterised by high perishability, leading to a limited postharvest shelf life. Consequently, preharvest elicitor application strategies have been explored to enhance their quality and storability. During the 2022 and 2023 seasons, figs (cv. Calabacita) grown under high-density conditions were treated with oxalic acid (OA; 1 and 2 mM), melatonin (MEL; 0.1 and 0.5 mM), and γ-aminobutyric acid (GABA; 10 and 50 mM) through foliar sprays applied two or three times. Fruits were harvested at commercial maturity and analysed immediately after harvest. Physicochemical and bioactive parameters were determined. Analysis of variance was used to assess treatment effects, and t-tests were used to evaluate differences in the number of applications and between seasons. Significant seasonal effects were observed, whereas no cumulative effect from repeated applications was detected. OA at 2 mM increased fruit weight (37.9 g) and size (42.5 mm) and delayed ripening. MEL treatments enhanced sugar accumulation (100.1 g kg⁻¹ and 96 g kg⁻¹ of glucose and fructose, respectively), while GABA treatments were associated with a more advanced maturity stage. Notably, OA (2 mM), MEL (0.5 mM), and GABA (50 mM) significantly increased enzymatic antioxidant activity by an average of 24% and non-enzymatic antioxidant capacity by around 17% in general terms. These results indicate that preharvest elicitor application is a promising and eco-friendly approach to improve the nutritional value and overall quality of fresh figs. Full article

Bifunctional materials present a promising route to develop advanced devices, yet the dual performance of CoNi₂S₄ nanosheets anchored on a porous scaffold is seldom reported. Herein, we propose a rational fabrication strategy to construct a three-dimensional hierarchical electrode via the in-situ growth of densely aligned CoNi₂S₄ nanosheets on a conductive fabric scaffold. This integrated porous architecture concurrently offers an ultrahigh specific surface area, efficient mass transport, and rapid electron conduction. As a supercapacitor, the electrode achieves a high areal capacitance of 3198 mF cm⁻² at 4 mA cm⁻² and retains 98.1% of its initial capacitance after 1000 cycles at 20 mA cm⁻². As a non-enzymatic glucose sensor, it exhibits outstanding selectivity (<4.1% interference), high sensitivity (1049 μA mM⁻¹ cm⁻²), a wide linear range (1–8 mM), and a low detection limit (1 μM). These results highlight the significant potential of this binder-free, scaffold-supported nanosheet design for advancing integrated energy storage and biosensing systems. Full article

Diabetes continues to impose significant global health and economic burdens, driving the demand for robust, enzyme-free glucose sensors capable of reliable operation under physiological conditions. Here, we report the development of a high-performance nonenzymatic glucose sensor based on laser-induced graphene (LIG) modified with zinc oxide (ZnO) and platinum (Pt) nanostructures. ZnO was electrodeposited onto LIG with modulation potential and deposition duration systematically optimized. The ZnO/LIG electrodes were characterized electrochemically using potassium ferricyanide and evaluated for glucose oxidation in phosphate-buffered solution. Subsequent electrodeposition of Pt under analogous optimized conditions yielded a ternary Pt/ZnO/LIG architecture with enhanced electrocatalytic activity. Sensor performance was assessed by cyclic voltammetry and chronoamperometry, with hydrodynamic conditions optimized for maximal response. The Pt/ZnO/LIG sensor demonstrated a high sensitivity of 37.125 µA mM⁻¹ cm⁻², a wide linear dynamic range (0.5–10 mM; 12–28 mM), and a low detection limit of 77.78 µM. The electrode exhibited excellent reproducibility, long-term stability over 7 weeks, and strong selectivity against common interfering species. Robust performance was also confirmed through real sample testing, highlighting its applicability in physiologically relevant matrices. These findings highlight the Pt/ZnO/LIG platform as a promising candidate for next-generation enzyme-free glucose monitoring systems for clinical and point-of-care diabetes management. Full article

Diabetes is a chronic metabolic disorder that poses a growing global health challenge, currently affecting nearly 500 million people. Over the past four decades, the rising prevalence of diabetes has highlighted the urgent need for innovations in monitoring and management. Traditional enzymatic methods, including those using glucose oxidase, glucose dehydrogenase, and hexokinase, are widely adopted due to their specificity and relative ease of use. However, they are hindered by issues of instability, environmental sensitivity, and interference from other biomolecules. Non-enzymatic sensors, which employ metals and nanomaterials for the direct oxidation of glucose, offer an attractive alternative. These platforms demonstrate higher sensitivity and cost-effectiveness, though they remain under refinement for routine use. Non-invasive glucose detection represents a futuristic leap in diabetes care. By leveraging alternative biofluids such as saliva, tears, sweat, and breath, these methods promise enhanced patient comfort and compliance. Nonetheless, their limited sensitivity continues to challenge widespread adoption. Looking forward, the integration of nanotechnology, wearable biosensors, and artificial intelligence paves the way for personalized, affordable, and patient-centered diabetes management, marking a transformative era in healthcare. This review explores the evolution of glucose monitoring, from early chemical assays to advanced state-of-the-art nanotechnology-based approaches. Full article

The detection of environmental toxicants is transitioning from centralized laboratory methods to decentralized, point-of-care (POC) monitoring. A highly innovative approach in this field is the repurposing of commercially available, low-cost, and portable personal glucose meters (PGMs) as universal biosensing platforms. This strategy leverages the widespread availability and ease of use of PGMs to develop rapid, on-site detection methods for a wide array of non-glucose targets, significantly reducing both cost and development time. This systematic review comprehensively examines the various strategies employed to adapt PGMs for the detection of a wide array of ecotoxicants, including chemical targets (antibiotics, mycotoxins, pesticides, heavy metals, persistent organic pollutants) and biological ones (pathogenic bacteria, and viruses). The systematic review critically evaluates different sensor designs, highlighting that while aptamer-based and non-enzymatic biosensors offer advantages in stability and cost, antibody-based sensors provide high specificity. A significant finding is the persistent trade-off between analytical sensitivity and practical field deployment; many of the most sensitive assays require multi-step procedures, precise temperature control, magnetic separation, centrifugation, and the use of additional equipment, factors that undermine true POC utility. To address this gap, we propose four essential criteria for POC readiness: (i) ambient-temperature operation, (ii) no reliance on magnetic or centrifugal separation, (iii) total assay time, and (iv) robustness in complex environmental matrices. This systematic review confirms the feasibility of this approach across a broad spectrum of targets. However, the key challenge for future research lies in simplifying the assay protocols, eliminating cumbersome sample preparation steps, and enhancing robustness to make these biosensors truly practical for routine, on-site environmental monitoring. Full article

ITIC’s superior electron-accepting capacity and efficient oxygen reduction motivated the design of a sensor to enhance sensitivity, selectivity, and stability over conventional oxygen-dependent or fullerene-based systems. As oxygen acts as the terminal reagent in enzymatic glucose oxidation, we developed an ITIC-mediated glucose oxidase (GOx) biosensor on glassy carbon (GCE) and screen-printed carbon electrodes (SPCE). ITIC, a non-fullerene organic semiconductor, was drop-cast onto the electrode to catalyze oxygen reduction, followed by GOx immobilization in a chitosan matrix. Scanning electron microscopy (SEM) confirmed uniform, ultrathin coatings without significant morphological changes upon ITIC and GOx deposition. Electrochemical studies (cyclic (CV) and differential pulse voltammetry (DPV)) revealed a distinct ITIC reduction peak at –0.7 V (vs. Ag/AgCl) and a glucose-dependent current decrease, consistent with mediated electron transfer during enzymatic oxidation. Under optimized conditions, the GCE-based biosensor showed a sensitivity of 10.7 μA L mmol⁻¹, a linear dynamic range (LDR) of 0.10–1.00 mmol L⁻¹, and detection (LOD)/quantification (LOQ) limits of 0.02 and 0.06 mmol L⁻¹, respectively. The SPCE device displayed sensitivity (3.8 μA L mmol⁻¹) and maintained excellent linearity (R² > 0.99) with LOD and LOQ of 0.05 and 0.16 mmol L⁻¹. Both platforms showed good precision (RSD < 5%) and reliable recovery in deproteinized plasma and artificial tears (90–104%). The superior performance of the GCE is attributed to higher ITIC loading, faster electron transfer, and reduced background current, while the SPCE offers a low-cost, disposable format with sufficient analytical performance for point-of-care glucose monitoring. Full article

Background/Objectives: This study reports pilot-scale production of gluten-free rice malt extract powder from Thai Chainat 1 rice as a sustainable alternative to barley malt extract. Methods: The process combined controlled malting with sequential enzymatic hydrolysis, optimized through bench-scale validation and scaled up to a 1500 L pilot system. Results: The resulting powder was rich in fermentable sugars (maltose 43.9 g/100 g, glucose 14.3 g/100 g), protein (5.2 g/100 g), γ-aminobutyric acid (GABA, 245.2 mg/100 g), and thiamine (0.64 mg/100 g), while free of detectable gluten, aflatoxins, and heavy metals. Microbiological quality met international safety standards. Shelf-life studies under ambient and accelerated conditions demonstrated chemical stability and bioactive retention for up to three years in laminated and HDPE packaging. Application trials confirmed that the rice malt extract powder supported yeast, bacterial, and mold growth comparably to commercial malt extract in culture media, with optimized yeast–mold agar formulations enabling direct substitution without supplementary glucose. The powder was further applied to a gluten-free malt beverage, yielding a beer-like product with acceptable physicochemical and nutritional quality, though residual alcohol levels exceeded the non-alcoholic threshold and required process optimization. Conclusions: Rice malt extract powder represents a safe, functional ingredient suitable for food, beverage, and industrial microbiology applications, offering opportunities to reduce import dependency and advance gluten-free innovation in emerging markets. Full article

Non-enzymatic glucose sensing has attracted considerable interest as a promising alternative to enzyme-based sensors, addressing limitations such as poor stability and high cost. To overcome the challenges of expensive noble metals and the inherent issues of pure copper oxide (CuO), including low conductivity and aggregation tendency, this study developed a composite sensing material based on two-dimensional CuO nanosheets decorated with gold nanoparticles (Au NPs). A series of Au/CuO nanocomposites with varying Au loadings were synthesized through a combined hydrothermal and in situ reduction approach. Systematic electrochemical characterization revealed that the composite with 7.41 wt% Au loading exhibited optimal sensing performance, achieving sensitivities of 394.29 and 257.14 μA·mM⁻¹·cm⁻² across dual linear ranges of 5–3550 μM and 4550–11,550 μM, respectively, with a detection limit of 10 μM and a rapid response time of 3 s. The sensor also demonstrated selectivity against common interferents as well as long-term stability. This work highlights the importance of precise noble metal loading control in optimizing sensor performance and offers a feasible material design strategy for developing high-performance non-enzymatic glucose sensors. Full article