Bioelectrochemistry最新文献

Phenolic compounds, including polyphenols and tannins, contribute to the sensory characteristics of wines and help protect them against oxidation through their reductive properties. Linear or cyclic voltammetry methods were previously reported to monitor specific wine phenolic compounds and decipher on their antioxidant activity. Pulsed voltammetry methods improve selectivity and accuracy and recently raised further interest for wine studies. We report the use of differential pulse voltammetry-DPV to characterize each wine redox profile and reactivity. Without any prior solution preparation, DPV analysis in wine provides curves displaying several oxidation peaks assigned to families of reductive phenolic acids or anthocyanins, flavonoids and tannins. Wine redox profiles vary as a function of their color, winemaking process, grape variety, vintage, etc. DPV and cyclic voltammetry-CV allowed further to study wines when changing their composition in caffeic and gallic acids, demonstrating the reactivity between phenolic species. Finally, the oxidation of a red wine under air and oxygen-saturated conditions was monitored by colorimetric and DPV analyses, directly showing the correlation between color browning, decrease of reductive ability and dissolved oxygen level. This work demonstrates the effectiveness of DPV in directly deciphering the oxidation-reduction processes occurring during winemaking and wine ageing.

A stable nanofluid containing ZnO nanoparticles (ZnO NPs) and a plant-based surfactant, soapnut, was synthesized and its composite nature established by thermogravimetry, Fourier-transform infrared spectroscopy, scanning electron microscopy, and energy dispersive X-ray (EDX) analyses. Its effectiveness as a microbially induced corrosion (MIC) inhibitor was investigated. Gravimetric and electrochemical techniques-potentiodynamic polarisation and electrochemical impedance spectroscopy, revealed a reduction in corrosion rates (from 31.63 to 1.17 mils/year), achieving an inhibition efficiency of up to 97% at a low nanofluid concentration of 4 vol%. Both the components- ZnO NPs and the soapnut extract (SN) exhibited pronounced bactericidal activity, leading to effective suppression of biofilm formation, as confirmed by biofilm inhibition assays (78%) and confocal laser scanning microscopy imaging. The amphiphilic nature of SN, together with the high surface availability of ZnO NPs, enhanced inhibitor adsorption on the metal surface which was supported by adsorption studies and surface analyses- field-emission scanning electron microscopy coupled with EDX. In the synthesized composite, SN acting as a ligand, prevented aggregation of ZnO NPs and thereby improved surface coverage and stability. Overall, the synergistic interaction between SN and ZnO NPs produced an environmentally benign nanofluid with strong potential for mitigating MIC in petrochemical pipeline systems.

A highly sensitive and selective label-free electrochemical immunosensor was developed to detect nuclear matrix protein 22 (NMP22), a bladder cancer marker, in urine. A screen-printed carbon electrode (SPCE) was modified with carboxylate graphene-supported thionine (Thi@Gr-COOH) as a redox probe, and a unique structure of ordered mesoporous carbon decorated with gold nanoparticles (AuNPs@OMC). The large active site and uniform porosity of OMC facilitated the deposition of AuNPs, significantly increasing the antibody coverage. NMP22 concentration was determined based on changes in the peak current of Thi reduction measured by differential pulse voltammetry before and after the formation of the immunocomplex. In the optimal condition, the proposed immunosensor demonstrated linearity of 1.0 × 10^-7 to 1.0 × 10^-1 ng mL^-1 with detection limit of 2.96 × 10^-8 ng mL^-1. Furthermore, the proposed sensor demonstrated good reproducibility, stability for over 20 days, reusability up to 5 cycles of binding and regeneration, and good selectivity. The developed electrochemical immunosensor effectively detected NMP22 in human urine samples, achieving good recoveries and results that matched the NMP22™ Bladderchek™ TEST, proving it can be used effectively.

Detecting psychoactive substances in biological samples presents significant challenges in clinical diagnostics, forensic analysis, and public health monitoring. This study introduces a highly sensitive electrochemical biosensing platform for the detection of cocaine, addressing the critical need for rapid, field-deployable testing methods. By integrating functionalized magnetic beads (MBs) with screen-printed carbon electrodes (SPCEs), we developed a competitive immunoassay system that leverages the superior molecular recognition capabilities of antibodies while maintaining operational simplicity. The biosensor operates via a competitive binding mechanism, in which cocaine present in the sample competes with cocaine-bovine serum albumin (BSA) conjugates immobilized on MBs for binding sites on horseradish peroxidase-labeled anti-cocaine antibodies (HRP-DAb). Electrochemical detection is achieved through amperometric measurement of enzyme activity using a redox system consisting of hydrogen peroxide/hydroquinone (H₂O₂/HQ). The optimized biosensor demonstrates excellent analytical performance with a linear response range from 0.3 to 300 ng mL^-1 and a detection limit of 0.1 ng mL^-1. Notably, the biosensor maintains its performance when analyzing cocaine in complex biological matrices, including human saliva and urine, successfully quantifying concentrations with minimal matrix interference. The platform offers significant advantages, including single-use disposable electrodes, rapid analysis time (< 30 min), minimal sample preparation requirements, and the potential for miniaturization into portable devices. These characteristics combined with high selectivity, a simple fabrication process, and cost-effectiveness, position this biosensor as a promising tool for point-of-care testing and field applications in clinical, forensic, and roadside testing scenarios.

The early and sensitive detection of cancer, a malignant disease posing significant threats to human health, is of strategic importance for disease prevention and control. This study employed 1,3,6,8-tetra(4-carboxyphenyl)pyrene (H₄TBAPy), a fluorophore exhibiting aggregation-caused quenching (ACQ), to construct a zinc-based metal-organic framework (Zn-TBAPy) serving as an energy donor platform. Polydopamine-coated ZIF-67 (ZIF-67@PDA) was employed as the energy acceptor to construct an electrochemiluminescence (ECL) immunosensor for sensitive carcinoembryonic antigen (CEA) detection. The advantages of ECL immunosensor are primarily manifested in the following three aspects: (1) Zn-TBAPy not only mitigates ACQ caused by polycyclic aromatic hydrocarbon π-π stacking but also enhances chromophore loading capacity and specific surface area. Relative to aggregate systems, the Zn-TBAPy exhibits a 2.5-fold enhancement in ECL signal intensity. (2) ZIF-67@PDA exhibits favorable broad-spectrum absorption characteristics and excellent quenching efficiency; as well as demonstrates superior biocompatibility for immunosensor construction. (3) The immunosensor was constructed through an electrochemiluminescence resonance energy transfer (ECL-RET) mechanism, yielding markedly improved sensitivity; the developed sensor demonstrated a linear detection range from100 fg·mL^-1 to 80 ng·mL^-1with LOD) of 0.275 pg·mL^-1. In conclusion, this study provides a valuable research strategy for the construction of immunosensors based on novel luminophore materials.

In current clinical practice, Tumor Treating Fields (TTFields) are delivered through insulated ceramic electrode arrays via capacitive coupling, which limits the efficiency of electric field energy transfer. In this study, we propose a new TTFields delivery mode based on conductive electrodes, termed conductive TTFields (Ce-TTFields), to enhance energy delivery efficiency. Electromagnetic-field and lumped-circuit analysis was conducted to understand the underlying mechanisms of TTFields delivery and proposed the novel Ce-TTFields concept. We designed and fabricated a Ce-TTFields culture dish and conducted electromagnetic simulations, in vitro electric-field measurements, and U-87 glioma cell proliferation assays to validate this novel concept. Simulation and test experimental results demonstrate that Ce-TTFields produce stronger electric field intensities in the cell culture and the simulated human brain model compared with conventional insulated electrodes under the same driving voltage. U-87 glioma cell proliferation assays consistently confirmed that the U-87 glioma inhibition efficiency is enhanced by Ce-TTFields, indicating significantly improved energy-delivery efficiency. These findings suggest that Ce-TTFields may help optimize TTFields treatment protocols and offer a promising direction for developing more efficient, lightweight, and cost-effective TTFields therapeutic systems.

Perovskite nanocrystals are attractive ECL emitters but suffer from poor water stability and potential toxicity. Here we report a signal-on electrochemiluminescent biosensor that integrates CsPbBr₃@SiO₂@Au nanocomposites with a CRISPR/Cas13a-Nb.BbvCI amplification cascade for ultrasensitive microRNA detection. The CsPbBr₃ core provides bright emission, a conformal SiO₂ shell enhances water compatibility and suppresses ion leakage, and surface Au nanoparticles offer abundant sites for thiolated ferrocene-hairpin (Fc-HP) immobilization. In the resting state, proximal Fc efficiently quenches the CsPbBr₃ ECL. Target miRNA activates Cas13a to cleave a dumbbell probe and release an intermediate strand that hybridizes with Fc-HP; subsequent Nb.BbvCI nicking removes Fc from the electrode and is recycled, producing robust signal restoration. Morphology (TEM), composition (EDS/XPS), and stepwise electrochemistry (CV/EIS) verify a core-shell-Au architecture and a reliably assembled interface that follows the expected quench→restore behavior. Under optimized conditions (0.5 mg mL^-1 CsPbBr₃@SiO₂@Au, 2.0 μM Fc-HP, 40 min target incubation, 100 mM TPrA, 120 s pre-reaction), the assay affords a 1 aM-1.0 × 10⁹ aM linear range with an estimated limit of detection (LOD) of 1.86 aM. The sensor shows high specificity against homologous sequences and achieves 95.22%-104.61% recoveries with RSD < 5% in spiked serum. Pilot measurements distinguish patient serum samples from healthy controls, underscoring clinical potential. This modular platform couples stable perovskite ECL emission with programmable CRISPR chemistry, offering a sensitive, selective, and water-compatible route for microRNA analysis and readily extensible nucleic-acid diagnostics.