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Quenched Sandwich-type Photoelectrochemical Aptasensor forProtein Detection based on Exciton Energy Transfer
摘要： This work proposes a quenched photoelectrochemical sensing method for highly selective and sensitive detection of protein via Energy Transfer (ET) effect between the AuNPs and CdS:Mn quantum dots. This detection was performed on a sandwich-type aptamer sensing interface. Chitosan modified CdS:Mn/TiO2/ITO electrode was used to immobilize capture DNA (S1) via -CONH- bond. In the presence of target protein, AuNPs labeled DNA (AuNPs-S2) was further bonded to the protein to fabricate sandwich sensing platform, which forced the AuNPs away from the electrode surface. In this state, the photocurrent was greatly depressed, mainly due to two factors: (a) the ET effect produced by interparticle distance between CdS:Mn and AuNPs; (b) the steric hindrance of AuNPs-S2 partly obstructs the diffusion of the electron donor. The photocurrent decreased with the increasing concentration of the target protein. Using thrombin as a target, this sensitized method showed a detectable range of 0.1 pM to 8 nM and a detection limit of 30 fM. It possessed high selectivity and good stability for detection of thrombin. This method is extremely flexible and can be extended to varieties of protein targets.
关键词： CdS:Mn,Photoelectrochemical aptasensor,Thrombin,Energy transfer,AuNPs
更新于2025-11-14 15:15:56
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2D-Porphrinic Covalent Organic Framework-Based Aptasensor with Enhanced Photoelectrochemical Response for the Detection of C-Reactive Protein
摘要： In this study, a novel photoelectrochemical (PEC) aptasensor based on two-dimensional (2D) porphyrinic covalent organic frameworks (p-COFs) for the label-free detection of C-reactive protein (CRP) is presented. The obtained p-COFs possess high conductivity and an improved stability due to strong and rigid covalent linkages. The introduction of p-COFs hinder the recombination of electrons and holes, decreasing their band gap (Eg), thereby which improved the photocurrent conversion efficiency. Compared with pure porphyrin, p-COFs exhibited enhanced photocurrent intensity. An amplified photocurrent conversion efficiency and enhanced photocurrent results from H2O2, which act as active molecules and electron donors. As an unprecedented application of COFs in PEC bioanalysis, the detection of CRP with a PEC aptasensor is presented. The assembly of a CRP aptamer on the surface of Ag nanoparticles hinders the electron transfer, resulting in the decrease of the photocurrent response. This PEC aptasensor exhibits good analytical performances such as a rapid response, high stability, wide linear range and excellent selectivity, making COFs promising candidates for PEC bioanalysis.
关键词： C-reactive protein,Porphyrinic covalent organic framework,High photocurrent conversion efficiency,Photoelectrochemical aptasensor,Enhanced photocurrent
更新于2025-09-23 15:22:29
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Plasmonic enhanced photoelectrochemical aptasensor with D-A F8BT/g-C3N4 heterojunction and AuNPs on a 3D-printed device
摘要： D-A F8BT/g-C3N4 type II heterojunction nanocomposite was employed as photoelectrode material for photoelectrochemical (PEC) aptasensor based on rolling circle amplification (RCA) with the assistance of 3D-printed device for carcinoembryonic antigen (CEA) detection. D-A type F8BT improved photocurrent response of g-C3N4 nanosheet after forming D-A F8BT/g-C3N4 type II heterojunction which effectively constructed built-in electric field and reduced electron-hole recombination. With the introduction of DNA-AuNP probes by π-stacking interaction, the local plasmon resonance (LSPR) of AuNPs enhanced local electric field, promoted the generation of electron-hole and further improved photocurrent response. When target CEA was in presence of sensing platform, sandwich construction was formed between two kinds of CEA aptamers and CEA on magnetic beads, triggering the RCA reaction to produce repeated sequences. Partial sequences of complementary-DNA in combination with RCA results was digested by Exo III enzyme to release signal-DNA, detaching DNA-AuNP probes from the surface of the F8BT/g-C3N4 by complementation, causing the attenuation of LSPR and the decrease of photocurrent response. Combing with 3D-printed device, this PEC aptasensor exhibited a linear response to CEA from 0.02 ng mL?1 to 50 ng mL?1 with detection limit of 6.7 pg mL?1, contributing to develop all organic polymer semiconductors as photoelectric materials in PEC study.
关键词： Type II heterojunction,Rolling circle amplification,Photoelectrochemical aptasensor,D-A F8BT/g-C3N4 nanocomposites,3D-printed device,Local surface plasmon resonance
更新于2025-09-23 15:19:57
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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