AgI Precipitation Induced Polarity Reversal with Formation of Z‑Type Heterojunction for Photoelectrochemical Sensing

Regulating photocurrent polarity is highly attractive for fabricating photoelectrochemical (PEC) biosensors with improved sensitivity and accuracy in practical samples. Here, a new approach that adopts the in situ generated AgI precipitate and AgNCs to reversal Bi2WO6 polarity with formation of Z-ty...

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Published in:Analytical chemistry (Washington) 2024-09, Vol.96 (37), p.14759-14765
Main Authors: Wu, Chou, Hao, Zhipeng, Deng, Hanmei, Jiang, Ying, Yuan, Ruo, Yuan, Yali
Format: Article
Language:English
Subjects:
Biosensing Techniques
Biosensors
Bismuth compounds
Electrochemical Techniques
Electrodes
Electron transfer
Exodeoxyribonucleases - chemistry
Exodeoxyribonucleases - metabolism
Exonuclease
Heterojunctions
Humans
Iodides
Limit of Detection
Medical research
MicroRNAs - analysis
miRNA
Nanospheres
Photochemical Processes
Photoelectric effect
Photoelectric emission
Photoelectricity
Polarity
Silver Compounds - chemistry
Tungstates
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Summary:Regulating photocurrent polarity is highly attractive for fabricating photoelectrochemical (PEC) biosensors with improved sensitivity and accuracy in practical samples. Here, a new approach that adopts the in situ generated AgI precipitate and AgNCs to reversal Bi2WO6 polarity with formation of Z-type heterojunction was proposed for the first time, which coupled with a high-efficient target conversion strategy of exonuclease III (Exo III)-assisted triple recycling amplification for sensing miRNA-21. The target-related DNA nanospheres in situ generated on electrode with loading of plentiful AgI and AgNCs not only endowed the photocurrent of Bi2WO6 switching from the anodic to cathodic one due to the changes in the electron transfer pathway but also formed AgI/AgNCs/Au/Bi2WO6 Z-type heterojunction to improve the photoelectric conversion efficiency for acquiring extremely enhanced PEC signal, thereby significantly avoiding the problem of high background signal derived from traditional unidirectional increasing/decreasing response and false-positive/false-negative. Experimental data showed that the PEC biosensor had a low detection limit down to 0.085 fM, providing a new polarity-reversal mechanism and expected application in diverse fields, including biomedical research and clinical diagnosis.
ISSN:0003-2700
1520-6882
1520-6882
DOI:10.1021/acs.analchem.4c01577