Search Results (634)

C-reactive protein (CRP) is one of the most essential biomarkers for the early detection of inflammation and infection. In this study, we developed a sensitive and selective electrochemical immunosensor for CRP detection, leveraging the unique properties of gold nanoparticles (AuNPs). A nanostructured layer of AuNPs was deposited onto a screen-printed carbon electrode (SPCE), followed by the formation of a self-assembled monolayer (SAM) of L-cysteine and EDC/sulfo-NHS chemistry. The antibody was covalently immobilized onto the modified electrode through optimized dual-crosslinking chemistry. Detection conditions were systematically optimized, with pH 8.0 in Tris buffer providing the best electrochemical response. Electrochemical characterization was performed using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and differential pulse voltammetry (DPV) in a 5 mM K₃[Fe(CN)₆]/K₄[Fe(CN)₆] redox probe solution containing 0.1 M KCl. CRP detection was achieved by monitoring the increase in charge transfer resistance (Rct) upon specific binding of the target CRP antigen to the immobilized antibody. Spiked recovery experiments showed spiked recovery rates ranging from 98.01% to 107.14%, with a standard deviation below 4%. Regeneration studies demonstrated high efficiency, confirming the suitability of the sensor interface for repeated and reliable measurements. Under optimized conditions, the immunosensor exhibited excellent analytical performance, including a low limit of detection (LOD) of 0.16 µg/mL, a wide linear detection range of 5–100 µg/mL, high selectivity against 13 potential interferents (including inflammatory cytokines), and good reproducibility with a relative standard deviation (RSD) of 3.69%. The sensor also showed strong stability, retaining more than 95% of its signal after 15 days, and high regeneration efficiency of 97% over seven cycles. These results highlight the strong potential of the proposed immunosensor for point-of-care (POC) applications due to its simple fabrication, cost-effectiveness, user accessibility, and robust analytical performance. Full article

Rising global demand for safe, high-quality foods has accelerated the development of rapid, sensitive, and cost-effective analytical technologies for detecting harmful substances and quality markers. Electrochemical sensors have emerged as promising tools for food safety monitoring due to their high sensitivity, fast response, portability, and affordability compared with conventional laboratory methods. This review highlights recent advances in nanostructured electrochemical sensors for detecting key food analytes, including antioxidants, mycotoxins, allergens, and flavor compounds in diverse food matrices. It examines advanced nanomaterials such as metal oxides, MXenes, doped carbon nitrides, and noble metal-decorated graphene, which enhance sensor performance through improved surface area, conductivity, and electrocatalytic activity. Integrated with screen-printed or glassy carbon electrodes, these materials achieve ultra-low detection limits, wide linear ranges, and strong selectivity in complex food systems. The review also explores next-generation applications such as NFC-enabled smart packaging for continuous, non-invasive monitoring across the supply chain. Emerging trends in miniaturization, multiplex sensing, and artificial intelligence are discussed, along with key challenges in translating laboratory innovations into practical commercial solutions for global food safety. Full article

A textile-based membraneless microfluidic microalgae–microbial solar cell (μmMSC) was developed for low-cost, flexible, and sustainable power generation. Unlike conventional systems, the proposed device utilizes a textile substrate, enabling mechanical flexibility and simplified fabrication. Microfluidic channels were patterned via screen printing using hydrophobic Ecoflex, and conductive electrodes were fabricated using PEDOT:PSS combined with Ag₂O and carbon nanotubes (MWCNT/SWCNT). At the anode, Synechocystis sp., Bacillus subtilis, and Shewanella oneidensis MR-1 were vertically co-cultured to enhance synergistic bioelectrochemical activity, while Scenedesmus obliquus was employed as a microalgae-based biocathode. Under these conditions, the μmMSC achieved a maximum current density of 144 μA cm⁻² and a peak power density of 17 μW cm⁻². These results demonstrate that the proposed textile-based μmMSC provides a promising platform for flexible bio-solar energy systems, with potential for wearable applications, while offering improved sustainability and scalability compared to conventional rigid device. Full article

Dopamine (DA) is essential for motor control, motivation, and cognition, and its dysregulation is associated with neurological and psychiatric disorders such as Parkinson’s disease, schizophrenia, and addiction. Accurate and selective DA quantification in complex biological matrices is important, but remains challenging because of coexisting interferents and the low physiological concentration of DA. Here, we report a disposable electrochemical DA sensor based on screen-printed carbon electrodes (SPCEs) modified with metal–organic framework-derived gold nanocomposites (MOFD-AuNCs). The optimal material, synthesized with a 60 min NaBH₄ reduction step (MOFD-AuNC-60), exhibited superior electron-transfer kinetics compared with materials prepared at other reduction times. A single coating of MOFD-AuNC-60 on SPCEs enabled DA oxidation at a low potential (~0.05 V) with high selectivity in the presence of ascorbic acid and uric acid. In undiluted porcine serum, the sensor exhibited a dynamic range of 2.5–500 nM with a calculated detection limit of 0.5 nM. In undiluted human serum, it exhibited a dynamic range of 5–100 nM with a calculated detection limit of 4.4 nM. The MOFD-AuNC-60/SPCEs further demonstrated excellent reproducibility (relative standard deviation, 3%) and stability (7.5% current loss over 7 days). These results demonstrate that the proposed sensor provides a disposable, robust, and reliable sensing platform for direct DA detection in undiluted serum, showing promise for practical applications. 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

In this study, the sintering behavior and electrical properties of 0.7Pb(Zr_0.46Ti_0.54)O₃ (PZT)–0.1Pb(Zn₁/₃Nb₂/₃)O₃ (PZN)–0.2Pb(Ni₁/₃Nb₂/₃)O₃ (PNN) piezoelectric ceramics with different Pb(Fe₂/₃W₁/₃)O₃ (PFW) doping contents were investigated to obtain a formulation that can be co-fired with silver (Ag) electrodes below 900 °C for multilayer ceramics. PFW was introduced as a sintering aid, which effectively reduced the sintering temperature of the ceramics from 1200 °C to 850 °C. The sample with x = 0.12 exhibited the largest average grain size of 1.72 μm, achieving excellent comprehensive properties with piezoelectric constant (d₃₃) = 477 pC/N, planar electromechanical coupling factor (k_p) = 0.68, dielectric loss tangent (tanδ) = 0.0154, and relative density of 98.2%. Furthermore, the feasibility of fabricating piezoelectric actuators based on this optimized composition was verified. Multilayer piezoelectric devices were prepared via screen printing combined with a carbon-based sacrificial layer method. No obvious interdiffusion was observed at the interface between the Ag internal electrodes and the ceramic matrix. The 9-layer device attained a high d₃₃ = 1470 pC/N and produced a large displacement of 5.5 μm (corresponding to a strain = 1.83%) with a voltage of 500 V. The thickness of the multilayer piezoelectric film was approximately 0.3 mm. Through this, the feasibility of manufacturing a multilayered actuator with an Ag electrode was confirmed through the composition of 0.58PZT–0.1PZN–0.2PNN–0.12PFW. Full article

This report presents a novel protocol for the recovery and utilization of recycled manganese oxide from used batteries through hydrothermal (HT) treatment. The recovered and treated material showed high activity towards rutin electro-oxidation (RT) on a screen-printed carbon electrode (SPCE) modified with recovered and treated MnO₂ within a hydrothermal reactor. Material characterization using scanning electron microscopy (SEM) and density distribution and particle size analysis revealed a more homogeneous and less dispersed particle size compared to the untreated material. This treatment increased the electroactive activity of the anodic current for RT by more than 70% compared to the SPCE without MnO₂ treated with HT. The electroanalytical application of this new electrode enabled the detection of RT, with a detection limit of 0.03 µmol/L, and its application in natural samples such as coffee and flavored beverages. Full article

The quantitative analysis of cardio selective beta-blockers, such as the antihypertensive and antiarrhythmic medication acebutolol (ABT), is critical for biomedical and environmental monitoring. This study describes the development of a high-performance electrochemical sensing platform for ABT based on a screen-printed carbon electrode (SPCE) modified with a silver nanoparticle/hexagonal boron nitride (Ag NPs/h-BN) nanocomposite. The morphological and structural properties of the synthesized materials were examined by using a microscopic and spectroscopic techniques. The Ag NPs/h-BN/SPCE demonstrated exceptional electrocatalytic activity toward ABT oxidation, characterized by a significant reduction in overpotential and a substantial enhancement in peak current relative to unmodified and mono-component electrodes. This superior performance is attributed to the synergistic integration of Ag NPs and h-BN, which provides a high density of active sites, an expanded electroactive surface area, and accelerated charge transfer kinetics. Under optimized experimental conditions, the sensor exhibited a broad linear dynamic range of 0.01–284 μM, a remarkably low limit of detection (LOD) of 0.0049 μM, and a high sensitivity of 0.873 µA µM⁻¹ cm⁻² for ABT detection. Furthermore, the platform displayed excellent selectivity in the presence of common interfering species and robust reproducibility (RSD of 4.8%). The practical utility of the Ag NPs/h-BN/SPCE was successfully validated through the precise quantification of ABT in complex biological and environmental matrices. This work provides a versatile strategy for the rational design of metal nanocatalysts confined within h-BN frameworks for the development of advanced electrochemical diagnostic tools. Full article

The rapid detection of organophosphorus (OP) compounds is crucial for safeguarding human health and ensuring food safety. This study presents a novel wearable electrochemical biosensor that integrates miniaturized screen-printed electrodes with wearable devices to achieve real-time, on-site OP detection. The biosensor was fabricated by constructing a screen-printed carbon electrode (SPCE) on a thermoplastic polyurethane (TPU) substrate, sequentially modified with graphene (GR), gold nanoparticles (AuNPs), and organophosphorus hydrolase (OPH), and finally encapsulated with Nafion. This SPCE/GR/AuNPs/OPH/Nafion configuration yields a highly flexible and portable device. The detection principle relies on the enzymatic hydrolysis of methyl paraoxon (MPOX) by OPH, generating p-nitrophenol (PNP), which is quantitatively measured via square wave voltammetry (SWV). The sensor exhibits a broad linear detection range (30–400 μM) with a strong linear correlation (R² = 0.995) and a low detection limit (0.321 μM). It demonstrates excellent selectivity against common interfering substances, including urea, sucrose, and various metal ions. Application to real-world samples such as cabbage and tap water yielded high recoveries (107.2% for cabbage and 101.2% for tap water), with relative standard deviations (RSDs) below 8%. Furthermore, the biosensor maintains robust flexibility and mechanical resilience, with less than 5% signal loss after 100 bending cycles, confirming its suitability for wearable applications and reliable operation under mechanical stress. This innovative, flexible electrochemical biosensor provides a powerful and reliable platform for rapid OP detection, particularly in complex testing environments. Full article

The development of reliable electrochemical interfaces for biosensor applications requires materials that combine high conductivity, large effective surface area, and suitable platforms for biomolecule immobilization. In this work, a hybrid electrochemical platform based on screen-printed carbon electrodes (SPCEs) modified with electropolymerized polypyrrole (PPy) and electrodeposited silver particles (AgPs) is presented for the subsequent immobilization of Ki-67 antibodies. PPy films were synthesized under optimized electrochemical conditions, producing homogeneous, porous, and electrochemically stable coatings that significantly enhanced the doping/undoping processes from 0.3280 C/0.3284 C to 0.3281 C/0.3284 C for SPCE and SPCE-PPy, respectively. Subsequently, silver particles were deposited onto the PPy matrix, resulting in a well-dispersed and uniform distribution of AgPs, promoted by the interaction between Ag⁰ and the nitrogen groups in the polymer backbone. The synergistic combination of PPy and AgPs resulted in improved charge-transfer properties and enhanced electrochemical reversibility, thereby decreasing the peak-to-peak separation of the ferricyanide/ferrocyanide redox couple used as a probe by 40%. Immobilization of Ki-67 antibodies was achieved via direct interaction with AgPs, resulting in a marked passivation effect, as evidenced by the suppression of redox probe signals, confirming successful biofunctionalization. The proposed SPCE-PPy-AgP architecture provides a robust, reproducible, and versatile platform for antibody immobilization, as demonstrated by oxidation and reduction peaks with relative standard deviations (RSDs) of 3.18% and 4.43%, respectively, highlighting its potential for developing label-free electrochemical immunosensors for clinically relevant proliferation biomarkers. Full article

Disruption of the intestinal barrier is a hallmark of inflammatory bowel disease (IBD) and drives both epithelial injury and neutrophil-mediated inflammation, yet rapid, multiplexed assessment of these processes remains an unmet clinical need. Intestinal fatty acid binding protein (iFABP) and fecal calprotectin (FC) provide complementary insights into barrier integrity and mucosal inflammation, but conventional ELISA-based assays are time-consuming, low-throughput, and require large sample volumes. Here, we introduce a dual electrochemical sandwich immunosensor enabling simultaneous quantification of iFABP and FC on screen-printed dual carbon electrodes (SPdCEs). Capture antibodies were immobilized via electrografting of p-aminobenzoic acid diazonium salt, while a V₂O₅/MWCNTs-HRP–streptavidin nanocomposite amplified the electrocatalytic reduction in hydrogen peroxide, enhancing sensitivity. The platform achieved detection limits of 0.01 pg mL⁻¹ (iFABP) and 1 pg mL⁻¹ (FC) with a total assay time of 1 h 20 min and sample volume of just 5 μL, outperforming conventional ELISA in speed and efficiency. High repeatability, reproducibility, and accurate recovery in enriched fecal samples confirmed analytical robustness. By integrating multiplexed detection, nanostructured signal amplification, and robust electrode engineering, this immunosensor provides a rapid, sensitive, and low-volume platform for point-of-care and decentralized monitoring of IBD, enabling timely clinical decision-making and longitudinal patient management. Full article

Electrochemical sensors are user-friendly devices designed for the rapid and straightforward detection of target analytes. Serotonin (5-hydroxytryptamine, 5-HT) is a key neurotransmitter and neuromodulator that regulates diverse neuronal processes. Using a custom-designed screen-printed carbon electrode (SPCE) incorporating ordered mesoporous carbon–bimetal oxides of Cu and Ni (CuO–NiO–OMC), rapid and real-time detection of 5-HT was achieved. The CuO–NiO–OMC structure featured highly active CuO and NiO catalytic sites that effectively promoted the irreversible oxidation of 5-HT (vs. Ag/AgCl reference electrode). The CuO–NiO–OMC/SPCE sensor, connected to a portable potentiostat, exhibited exceptional electrocatalytic performance for the oxidation of 5-HT, with a detection limit of 42.5 nM. The sensitivity was 1.56 A M⁻¹ cm⁻², and the linear dynamic range was 0.0–80.0 µM. The CuO–NiO–OMC/SPCE sensor also demonstrated outstanding selectivity in the presence of competing neurochemicals, including norepinephrine, epinephrine, dopamine, and glutamate, as well as high concentrations of tested biomolecules and inorganic ions. Furthermore, the practicality of the sensor was demonstrated using human serum and urine samples, with recovery percentages ranging from 91.1% to 98.3%. Thus, the CuO–NiO–OMC/SPCE sensor offers an effective approach for 5-HT sensing, thereby permitting molecular-level understanding of brain function. Full article

Candida albicans (C. albicans) is an opportunistic fungal pathogen and a major cause of nosocomial infections, especially in immunocompromised patients. Conventional diagnostic approaches such as blood culture and biochemical assays are accurate but require multi-step sample processing and prolonged turnaround times, limiting their applicability for rapid clinical screening. In the present study, we developed an electrochemical biosensor based on molecularly imprinted polymer (MIP) technology for the rapid and selective detection of intact C. albicans cells. The MIP layer was electropolymerized onto a screen-printed carbon electrode (SPCE), forming selective recognition cavities complementary to the fungal morphology. Electrochemical characterization and detection were performed using cyclic voltammetry in phosphate-buffered saline (PBS). The system demonstrated a wide linear detection range, enabling reliable quantification of C. albicans across concentrations spanning from 1 to 10⁴ CFU/mL and achieved an ultralow limit of detection (LOD) of 1.30 CFU/mL, demonstrating high sensitivity. High selectivity was confirmed against E. coli, S. aureus, and P. aeruginosa, demonstrating that the imprinted cavities effectively distinguish fungal cells from bacterial contaminants. These findings highlight the promise of MIP-based electrochemical biosensors as a simple, low-cost, and portable alternative for early fungal diagnostics. Full article

This study presents a low-cost, small-scale single-chamber microbial fuel cell (MFC) toxicity biosensor fabricated on a printed circuit board (PCB) and a 3D-printed chamber with a volume of 120 μL. The anode consists of a screen-printed carbon electrode on the PCB, while the air cathode is a carbon paper electrode. To address poor adhesion of microorganisms to the smooth anode surface, femtosecond laser processing was used to fabricate a micropore array with 40 μm pores on the electrode. This method can create micropores on the anode surface without damaging the screen-printed electrodes, the PCB substrate, or the pads. These micropores increase the anode’s surface area and hydrophilicity, allowing more microbial coatings to firmly adhere to its surface. In this study, the MFC utilised Rhizobium rosettiformans W3, extracted from activated sludge at a wastewater treatment plant, as the anode microorganism. Its aerobic nature simplifies the design of MFCs, enabling a single-chamber structure and miniaturisation. Using formaldehyde solution as a toxicity sample to test the biosensor’s performance, a 0.1% concentration significantly reduced the sensor’s output power. Full article

Bovine rotavirus (BRV) is one of the leading causes of neonatal diarrhea in calves and remains a major concern in veterinary medicine due to its high morbidity and economic impact. Rapid, sensitive, and cost-effective diagnostic approaches are therefore required for early detection and disease control. In this study, electrochemical immunosensors were developed for the detection of BRV with the aim of improving existing multiplex diagnostic strategies. Screen-printed carbon electrodes (SPEs) were employed as the sensing platform and modified with molybdenum disulfide nanoparticles (MoS₂ NPs) to enhance electrochemical performance. Mouse monoclonal antibodies against the BRV VP6 protein were immobilized onto the electrode surface, followed by blocking with bovine serum albumin. BRV detection was carried out using differential pulse voltammetry, cyclic voltammetry, and electrochemical impedance spectroscopy. To further improve sensitivity, a sandwich immunoassay format was constructed using gold nanoparticle-labeled secondary antibodies. The MoS₂-modified sandwich immunosensor exhibited superior analytical performance, achieving a limit of detection of 1.11 ng/mL, a limit of quantification of 3.72 ng/mL, a relative standard deviation of 1.89% (n = 5), and a linear response with R² = 0.99. The developed immunosensors demonstrated reliable performance in real sample analysis, with a selectivity rate of 100 ± 2.95%. These findings suggest that MoS₂-based electrochemical immunosensors offer a promising platform for rapid and sensitive BRV detection and have potential applications in veterinary diagnostics. Full article