Signal-off photoelectrochemical determination of miRNA-21 using aptamer-modified In.sub.2O.sub.3@Cu.sub.2MoS.sub.4 nanocomposite

In.sub.2O.sub.3@Cu.sub.2MoS.sub.4 nanocomposite with superior photoelectrochemical (PEC) performance is used for the first time as a photoactivity material, and a signal-off PEC biosensing platform for miRNA detection has been successfully constructed. Firstly, the Cu.sub.2MoS.sub.4 nanosheets are s...

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Published inMikrochimica acta (1966) Vol. 187; no. 10
Main Authors Yu, Ling Dan, Wen, Yu Xia, Zhang, Xing Yue, Li, Nian Bing, Luo, Hong Qun
Format Journal Article
LanguageEnglish
Published Springer 01.10.2020
Subjects
Detectors
MicroRNA
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Summary:In.sub.2O.sub.3@Cu.sub.2MoS.sub.4 nanocomposite with superior photoelectrochemical (PEC) performance is used for the first time as a photoactivity material, and a signal-off PEC biosensing platform for miRNA detection has been successfully constructed. Firstly, the Cu.sub.2MoS.sub.4 nanosheets are synthesized by a hydrothermal method, and then, the homogeneous In.sub.2O.sub.3 nanoparticles (In.sub.2O.sub.3 NPs) are synthesized by calcination in the air. The In.sub.2O.sub.3@Cu.sub.2MoS.sub.4 nanocomposite is constructed with the Cu.sub.2MoS.sub.4 nanosheets as matrix and In.sub.2O.sub.3 NPs as sensitizer through a layer-by-layer assembly strategy. The nanocomposite with a tight interface and the matched band structure restrains the electron-hole pair recombination. Under visible light (400-700 nm), the nanocomposite exhibits a strong initial signal. With the catalyzed hairpin assembly, dozens of PbS quantum dots (QDs) are introduced on the surface of an electrode, significantly reducing the photocurrent of n-type In.sub.2O.sub.3@Cu.sub.2MoS.sub.4. Since PbS QDs can compete with the nanocomposite for light energy and electron donors, the signal decreased. Under optimal conditions, the biosensor manifests a broad linear range (1 fM-1 nM) and a low detection limit of about 0.57 fM, at a working potential of 0 V (vs. Ag/AgCl). The recovery of spiked human serum is between 94.0 and 102%, and the relative standard deviation (RSD) is between 1.3 and 2.7%. Therefore, the as-fabricated biosensor exhibits a potential for the determination of miRNA-21 in practical applications. Graphical abstract
ISSN:0026-3672
1436-5073
DOI:10.1007/s00604-020-04540-z