期刊
BIOSENSORS & BIOELECTRONICS
卷 147, 期 -, 页码 -出版社
ELSEVIER ADVANCED TECHNOLOGY
DOI: 10.1016/j.bios.2019.111786
关键词
Photoelectrochemical; Signal-switchable; Triple helix molecular switch; Type-II CdTe@CdSe QDs; Prostate-specific antigen
类别
资金
- Taishan Scholars Program [ts201712048]
- National Natural Science Foundation of China [21874055]
- Major Program of Shandong Province Natural Science Foundation [ZR2017ZC0124]
- project of 20 items of University of Jinan [2018GXRC001]
Herein, a new on-off-on signal switch system combined triple helix molecular switch with efficient charge separation and transfer between different sensitization units was designed for the ultrasensitive photoelectrochemical (PEC) determination of prostate-specific antigen (PSA). Concretely, the initial signal-on state was obtained via the cascaded sensitization structure consisting of type-II CdTe@CdSe core-shell quantum dots (QDs), CdS QDs, and ZnO nanotubes, which were assembled on Au nanoparticles modified paper fibers with the aid of signal transduction probe (STP). Thereinto, the type-II CdTe@CdSe QDs with hole-localizing core and electron-localizing shell could enable the ultrafast charge transfer and retard the charge recombination, magnifying the initial photocurrent response and preserving the high efficiency of signal-switchable PEC aptasensing system. Subsequently, the PSA aptamer (PSA-Apt) modified with gold nanoparticles (GNPs) was introduced by the hybridization of PSA-Apt with STP and the hairpin configuration of STP changed from closed to open state, forming a triple-helix structure. Hence, the CdTe@CdSe QDs labeled on the terminal of STP moved away from the electrode surface while the GNPs kept attached close to it. The proposed aptasensor turned to signal-off state because of the dual inhibition of vanished cosensitization effect and signal quenching effect of GNPs. Upon the target recognition, the triple-helix structure was perturbed with the formation of DNA-protein complex and the recovery of STP hairpin structure, resulting in the second switch-on state. Based on the target-induced photocurrent enhancement, the proposed PEC aptasensor was utilized for the determination of PSA with high sensitivity, persuasive selectivity, and excellent stability.
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