- 标题
- 摘要
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- 实验方案
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Enzyme-free “on-off-on” photoelectrochemical biosensor based on cascaded quadratic amplification strategy for miRNA 141 detection
摘要： MicroRNAs (miRNAs) assay is of great significance for early diagnosis of diseases, so an enzyme-free “on-off-on” PEC biosensor has been developed for sensitive miRNA 141 determination. Manganese-doped cadmium sulfide coupled with zinc sulfide quantum dots (Mn:CdS@ZnS QDs) and manganese porphyrin (MnPP) have been used as photoelectric material and photosensitizer, respectively. And a high photocurrent of approximately 70.0 μA has been obtained. Cascaded quadratic amplification strategy has been applied in the system. Mn:CdS@ZnS QDs was characterized by transmission electron microscopy (TEM), scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS) and energy dispersive X-ray spectroscopy (EDX). Photoelectrochemical and electrochemical technologies were used to monitor the fabrication process of the biosensor. The sensing platform exhibits recommendable stability and good selectivity, miRNA 141 can be accurately quantified with a linear range of 1.00 × 10-14 to 1.00 × 10-8 mol·L-1 and the detection limit of 3.30 fmol·L-1. This method provides promising potential to explore sensitive detection models for various biological molecules.
关键词： Hybridization chain reaction,Catalytic hairpin assembly,Manganese-doped cadmium sulfide coupled with zinc sulfide quantum dots,MiRNA 141,Photoelectrochemistry,On-off-on
更新于2025-11-14 17:03:37
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Ultrasensitive Photoelectrochemical Assay with PTB7-Th/CdTe QDs Sensitized Structure as Signal Tag and 4-CD Precipitate as Efficient Quencher
摘要： Herein, an ultrasensitive photoelectrochemical (PEC) assay was developed for the monitoring of microRNA-141 (miRNA-141) based on poly{4,8-bis[5-(2-ethylhexyl)thiophen-2-yl]benzo[1,2-b:4,5-b′]dithiophene-2,6-diyl-alt-3-fluoro-2-[(2-ethylhexyl)-carbonyl]thieno[3,4-b]thiophene-4,6-diyl} (PTB7-Th)/CdTe quantum dots (CdTe QDs) sensitized structure as signal tag and the benzo-4-chloro-hexadienone (4-CD) precipitate as efficient quencher. PTB7-Th and CdTe QDs were successively modified on electrode surface to form a novel sensitized structure with eminent photovoltaic performances and surpassing film-forming ability. The PTB7-Th/CdTe QDs sensitized structure was served as signal tag for achieving a strong initial PEC signal. Besides, a tiny amount of target (miRNA-141) could be transformed into numerous DNA product via enzyme-assisted target cycling procedure, which further triggered the formation of DNA supersanwich structure on electrode surface for loading abundant manganese porphyrin (MnPP). Thereafter, MnPP as mimetic enzyme could catalyze 4-chloro-1-naphthol (4-CN) to generate 4-CD precipitate on sensing interface in the presence of H2O2, which could efficiently block electron transfer, leading to a significantly quenched PEC signal for determination of miRNA-141. The designed PEC biosensor performed a wide detection range from 0.1 fM to 1 nM with a low detection limit of 33 aM for miRNA-141, which paved a new avenue for highly accurate and ultrasensitive monitoring of multifarious analytes in bioanalysis and clinical diagnosis.
关键词： 4-CD precipitate,photoelectrochemical assay,ultrasensitive monitoring,miRNA-141,PTB7-Th/CdTe QDs,signal tag
更新于2025-09-10 09:29:36