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CdS quantum dots/Au nanoparticles/ZnO nanowire array for self-powered photoelectrochemical detection of Escherichia coli O157:H7
摘要： In this paper, the hydrothermally grown ZnO nanowire array (NWs) was modified by Au nanoparticles (NPs) and CdS quantum dots (QDs) to construct a high-performance photoelectrochemical (PEC) electrode. The aligned ZnO NWs, which decorated Au NPs and CdS QDs have the effective light absorption range from UV to visible region. This hybrid structure provided a self-powered PEC electrode with a favorable energy-band configuration for fast charge separation and transportation. Meanwhile, the Au NPs and CdS QDs also made increase of the surface area to improve the immobilization of the analytes. After assembling aptamer as recognition element, this composite nanoarray was further developed as a self-powered PEC biosensor by synergizing above multiple enhancement factors. The PEC aptasensor exhibited a rapid response in a wide linear range of 10-107 CFU/mL with the detection limit as low as 1.125 CFU/mL to Escherichia coli O157:H7 (E. coli O157:H7). This approach would offer an alternative PEC transduction for fast environment monitoring and clinical diagnosis related to pathogenic bacteria.
关键词： E. coli O157:H7,self-powered,photoelectrochemical,aptasensor
更新于2025-09-11 14:15:04
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A Label-free Photoelectrochemical Aptasensor Based on N-GQDs Sensitized Zn-SnS2 for Aflatoxin B1 Detection
摘要： A new label-free aptasensor with high visible-light photoelectrochemical (PEC) activity was fabricated for the detection of AFB1 based on N-doped graphene quantum dots (N-GQDs) sensitized Zn doped SnS2 (Zn-SnS2) nanocomposites. N-GQDs sensitized Zn-SnS2 showed eminent PEC performance. Ascorbic acid was utilized as an efficient electron donor for scavenging photogenerated holes and inhibiting light driven electron-hole pair recombination. Under the optimum experimental conditions, the specific binding between AFB1 aptamer and AFB1 resulted in the linear decrease of photocurrent with the increase of logarithm of AFB1 concentration in the range of 0.01 ng mL-1 to 20 ng mL-1 with a detection limit of 3 pg mL-1. The constructed N-GQDs sensitized Zn-SnS2 PEC aptasensor exhibited high sensitivity, low cost and good reproducibility, which is a promising platform for the detection of other important analytes.
关键词： photoelectrochemical aptasensor,N-GQDs,Zn-SnS2,AFB1
更新于2025-09-09 09:28:46
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Two-dimensional porphyrin-based covalent organic framework: A novel platform for sensitive epidermal growth factor receptor and living cancer cell detection
摘要： A porphyrin-based covalent organic framework (denoted as p-COF) was synthesized by a simple oil-bath method and exploited as a novel sensing layer for immobilizing epidermal growth factor receptor (EGFR)-targeting aptamer strands to detect trace EGFR and living michigan cancer foundation-7 (MCF-7) cells for the first time. p-COF presented a nanosheet-like structure, large cavities, rich nitrogen-bearing groups, high electrochemical activity, excellent bioaffinity, low toxicity, and good stability in aqueous solution; the microstructural features of this material enabled strong immobilization of the aptamer strands. Interactions between the aptamer strands and EGFR significantly changed the electrochemical signals of the modified electrode due to the formation of an aptamer-EGFR complex. The p-COF-based aptasensor exhibited an extremely low detection limit (LOD) of 5.64 fg?mL?1 obtained from differential pulse voltammetry and 7.54 fg?mL?1 originated from electrochemical impedance spectroscopy with a broad linear detection range of 0.05–100 pg?mL?1 of the EGFR concentration. When detecting living MCF-7 cells, the p-COF-based aptasensor showed an LOD of 61 cell?mL?1 with a linear detection range of 500 × 105 cell?mL?1. The fabricated aptasensor exhibited high selectivity, good stability, reproducibility, acceptable recyclability, and favorable applicability in human serum samples. We believe that the developed p-COF-based aptasensor is a potential candidate for the sensitive detection of target cancer markers or living cells.
关键词： Detection of epidermal growth factor receptor,Living cancer cell detection,Porphyrin-based covalent organic framework,Electrochemical aptasensor
更新于2025-09-09 09:28:46
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Multifunctional Magnetic Bead-Based Dynamic Light Scattering Aptasensor with Rapid and Feasible Determination of Disease-Related Biomarkers
摘要： A simple and feasible sensing strategy based on target-induced aggregation of aptasensor-conjugated multifunctional magnetic beads was designed for sensitive detection of low-abundant proteins (carcinoembryonic antigen, CEA, used as an example), coupling with dynamic light scatting technique.
关键词： Aptasensor,Cancer markers,Magnetic beads,Dynamic light scattering
更新于2025-09-04 15:30:14
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A glassy carbon electrode modified with TiO2(200)-rGO hybrid nanosheets for aptamer based impedimetric determination of the prostate specific antigen
摘要： TiO2(200)-rGO hybrid nanosheets were synthesized starting from TiO2, rGO and NaOH solid powders via a scalable hydrothermal process. The weight ratio of TiO2-GO was found to be crucial on the crystal growth and biosensor properties of the final hybrid nanosheets. They were characterized by means of SEM, FESEM-EDX, XRD, XPS, Raman and FTIR spectroscopies in order to verify the formation of very thin TiO2 anatase nanosheets with an orientation of the anatase crystal structure towards the (200) plane. The free active sites of TiO2 structure and the large surface of the 2D graphene structure strongly facilitate charge transport confirmed by BET-BJH analyses. Compared to pure AuNPs, rGO and TiO2, the hybrid nanosheet modified electrode represents the most sensitive aptasensing platform for the determination of PSA. The detection was based on that the variation of electron transfer resistance (Rct) at the modified electrode surface in a solution containing 3.0 mmol L?1 [Fe(CN)6]3?/4- as a redox probe and 0.1 mol L?1 KCl as supporting electrolyte. The detection limit of the sensor is 1 pg mL?1, and the sensor can be operated up to 30 days. It was applied to the analysis of PSA levels in spiked serum samples obtained from patients with prostate cancer. Data compare well with those obtained by an immunoradiometric assay.
关键词： X-ray photoelectron spectroscopy,Effective surface area,Electrochemical impedance spectroscopy,Aptasensor,Voltammetry,Work function
更新于2025-09-04 15:30:14