In this work, we report a novel electrochemical sensor based on a carbon black-incorporated hydrogel-modified screen-printed carbon electrode (CB@hydrogel/ SPCE) for the sensitive and selective detection of L-cysteine (L-Cys). The synergistic combination of conductive carbon black and porous carbon black-alginate/acrylamide hydrogel matrix enhanced the electroactive surface area and facilitated rapid electron transfer, which significantly improved the sensor performance. The CB-hydrogel was characterized by Field Emission Scanning Electron Microscopy (FE-SEM): Fourier transform infrared spectroscopy (FTIR): Cyclic Voltammetry (CV): and Differential Pulse Voltammetry (DPV) techniques. DPV studies revealed the electrochemical oxidation of L-Cys on CB@hydrogel/SPCE followed a diffusion-controlled and quasi-reversible mechanism involving a two-electron transfer process. The sensor exhibited a wide linear range from 5 to 170 µM, with a sensitivity of 1.8 µA mM−1 cm−2, limit of detection (LOD) of 1.26 µM, and limit of quantification (LOQ) of 3.83 µM. The sensor demonstrated an excellent selectivity against common interferents such as ascorbic acid, uric acid, glucose, and dopamine. The practical applicability of the sensor was validated by successful quantification of L-Cys in spiked real samples, including apple juice, orange juice, and yogurt, with high recovery rates and minimal matrix effects. These findings highlight the potential of the CB@hydrogel/SPCE platform for reliable and accurate electrochemical detection of L-Cys in complex food matrices.

Chemical agents present significant threat to international peace, security, and human health due to their potential toxicity. Therefore, developing a sensitive, rapid, and on-site detection method is of great importance. Herein, we developed a highly sensitive and selective glove-based electrochemical sensor based on a metal-organic-framework-modified screen printed electrode (SPE) for chemical agent marker detection. Layered copper benzene-1,3,5-tricarboxylate (Cu-BTC) was successfully constructed to modify screen-printed electrodes (SPE) for detecting electrically inactive ethyl methyl phosphonate (EMPA) and isopropyl methyl phosphonate (IMPA). Additionally, gold nanoparticles (AuNPs) reduced by plasma technology have been applied to create gold nanoparticle-encapsulated copper benzene-1,3,5-tricarboxylate-modified screen-printed electrode (Au@Cu-BTC/SPE) composites for detecting thiodiglycol (TDG). The large surface area and porous structure of Cu-BTC and Au@Cu-BTC enhance the target adsorption and ion diffusion and the efficient use of catalytic materials for rapid electron transfer and zero-distance catalysis. The limit of detection (LOD) was determined to be 4.13 × 10-16 M for EMPA, 7.46 × 10-12 M for IMPA, and 4.05 × 10-12 M for TDG. Following multiple cycles and extended exposure, the sensor demonstrated exceptional repeatability and stability. The response current of Cu-BTC to EMPA and IMPA decreased by 6.75% and 4.86%, and the peak value of Au@Cu-BTC to TDG decreased by 3.3% after 4 weeks, respectively. The peak current showed a good linear relationship with the concentrations of the three target substances, with R2 values all greater than 0.99. The interaction mechanism between the modified electrode and the targets was investigated by density functional theory (DFT) with the generalized gradient approximation of the PBE functional. The results showed that compared with other metal ions, Cu2+ could coordinate tighter with organophosphates. The established MOF-modified SPE integrated with a protective glove sensor was applied for the detection of real-world samples and demonstrated a broad spectrum of practical applications.

Screen-printing technology enables mass production of disposable electrochemical sensors on diverse substrates, such as ceramic, paper and polymer films. Two fully custom conductive inks-multi-walled carbon nanotube (MWCNT) and MWCNT/Prussian blue (PB)-together with a lab-made Ag paste was formulated for scalable printing of flexible screen-printed electrodes (SPEs) on cellulose and acetate substrates. Prior to printing, the inks were first characterized by scanning electron microscopy/x-ray diffraction/Fourier transform infrared spectroscopy and then optimized for shear-thinning rheology and high conductivity. The resulting SPEs exhibited diffusion-controlled behavior and good reproducibility. As a practical demonstration, SPEs printed on office paper detected bisphenol A in tap water with a limit of detection (LOD) of 0.084µM with a sensitivity of 1.3µA · mM-1· cm-2. In addition, SPEs with PB showed a linear amperometric response to H2O2with an LOD of 5.3µM (R2of 0.95). These results highlight a low-cost, scalable fabrication strategy for SPEs with applications in environmental monitoring and point-of-care testing, especially in resource-limited settings.

Urinary glucose, creatinine, and uric acid are vital biomarkers for diabetes and kidney disease management. However, multiplex point-of-care detection faces challenges due to insufficient sensitivity in complex urine matrices and signal cross-talk from interfering species. To address this, we developed an artificial intelligence (AI)-assisted microfluidic paper-based analytical device (μPAD) for simultaneous electrochemical quantification of these biomarkers. Screen-printed electrodes (SPEs) were modified with gold (Au)-platinum (Pt) bimetallic nanoparticles (NPs), leveraging their synergistic electrocatalysis to enhance hydrogen peroxide oxidation sensitivity by 25.4-fold. The optimized μPAD achieved rapid (<180 s) detection with low limits of detection (glucose: 10.1 μM; uric acid: 0.39 μM; creatinine: 141.7 μM) across clinically relevant ranges. Crucially, three multilayer perceptron (MLP) neural networks were applied to correct interference-induced errors, reducing mean absolute quantification errors from 30.9% to 6.3% (glucose) and 35.8% to 5.1% (creatinine). This integration of Au-Pt catalysis, pump-free μPAD design, and AI calibration enables highly sensitive and selective multiplex detection in urine. The developed platform demonstrates significant potential for decentralized diagnostics and longitudinal monitoring of diabetes and kidney injury.

Vaccine-induced seropositivity (VISP) causes antibodies produced by HIV-1 vaccines to react with standard serological tests, complicating diagnosis and leading to false positives. To distinguish VISP from true HIV infections, we developed a rapid, multiplexed companion electrochemical assay that integrates a three-dimensional–printed device with screen-printed electrodes coated with antigen, antibody, and methylene blue–labeled antisense oligonucleotide probes. The test delivers quantitative results within 5 minutes with calculated analytical limits of detection of 5.88 picograms per milliliter for p24 antigen, 10.96 picograms per milliliter for anti-p24 antibody, and 1259 copies per milliliter for HIV-1 RNA, with minimal cross-reactivity. Clinical testing with 104 plasma samples obtained from vaccinated/unvaccinated, HIV-positive/negative individuals demonstrated 95% sensitivity and 98% specificity in distinguishing active HIV-1 infection from VISP cases. Receiver operating characteristic analysis produced area under the curve values of 0.9888 for HIV-1 RNA, 0.9705 for anti-p24 antibody, and 0.9356 for p24 antigen. These findings highlight the potential to reduce false-positive results caused by VISP by integrating this diagnostic test in clinical trials and large-scale vaccination programs.

Acoustic streaming on antibody-functionalized screen-printed electrode enhances detection sensitivity and total assay duration for voltammetric immunosensing of newcastle disease virus.

Polishing, cleaning, and activation of solid electrode surfaces are common in electrochemistry; however, they are often labor-intensive, operator-dependent, and poorly reproducible. In the context of large-scale production of disposable solid-state sensors, such as screen-printed electrodes (SPEs), traditional surface conditioning procedures have proven to be impractical and incompatible with automated workflows. Here, we report the development of a low-cost robotic system that integrates a Tesla coil-based air-plasma generator with a Python-controlled XY motion platform for rapid (∼15 s per 0.11 cm2) and reproducible surface activation of SPEs. The main novelty of this study lies in the mechanization and reproducibility of the plasma activation process, achieved through the integration of a robotic platform with an air-plasma generator to enable standardized and scalable electrode conditioning. Morphological and Raman spectroscopic analyses revealed significant surface restructuring after plasma activation, leading to reduced charge-transfer resistance (from 7.10 to 0.45 kΩ), increased electron-transfer kinetics (∼4-fold increase in k0), increased electroactive area (from 0.073 to 0.270 cm2), and improved interelectrode reproducibility (RSD from 9.7 to 0.8%). The treatment also restored the voltammetric performance of carbon, gold, and platinum SPEs stored for over ten years. Plasma-treated carbon SPEs enabled the voltammetric determination of picric acid in simulated explosive samples (linear range: 0.5-50.0 μmol L-1; LOD: 0.1 μmol L-1). Moreover, 3D-printed electrodes were also successfully treated by using this system. This robotic plasma system provides a low-cost, scalable, and ecofriendly strategy for standardized activation of disposable electrodes, enhancing or restoring their electrochemical performance for routine analytical and industrial applications.

Portable multimodal sensor for chiral drug recognition: β-Cyclodextrin-quantum dot synergy on screen-printed electrodes

Smartphone-enabled detection of urea in animal feed based on a disposable electrode modified with silver nanoparticles decorated on nitrogen-doped graphene nanoplatelets.

Development of a wireless vitamin B2 sensor by using flexible and disposable screen-printed electrode modified with g-C3N4 based ternary composite.

Early detection of viable microorganisms in “sterile” periprosthetic fluids in implant-based breast reconstruction: a bioelectrochemical approach using screen-printed electrodes

Porous microneedle-mediated continuous glucose monitoring based on reverse iontophoresis.

Ultrasensitive electrochemical aptasensor for Pseudomonas aeruginosa detection using N-doped MWCNTs/AgNPs nanocomposite.

Fast Zinc determination using commercial screen-printed carbon electrodes modified with bismuth nanostructures via pulsed electrodeposition

Electrochemical dengue sensor based on NS1 epitope-imprinted polymers.

Laser ablation of screen-printed carbon electrodes for portable glucose sensing

Development of reusable screen-printed ion-selective electrodes with calibration-free operation

Impedimetric biosensor based on gold nanostructures and concanavalin A for glycoproteins detection.

Optimizing the geometry of screen-printed interdigital electrode for high-performance flexible fabric-based supercapacitors

A screen-printed carbon electrode immobilized MXene-gold nanoparticles composite detects creatinine in micro-volume of human serum samples