Ultrasensitive label-free photoelectrochemical immunosensor for the detection of amyloid β-protein based on Zn:SnO2/SnS2-Au nanocomposites

Publication date: Available online 12 December 2019Source: Sensors and Actuators B: ChemicalAuthor(s): Ning Gao, Yifeng Zhang, Keke Gao, Jiandong Xie, Lei Liu, Yuyang Li, Liping Qiu, Qin Wei, Hongmin Ma, Xuehui PangAbstractIn this work, an ultrasensitive label-free photoelectrochemical (PEC) immunosensor was designed for the detection of amyloid β-protein (Aβ). Specifically, Zn:SnO2/SnS2 nanocomposites were successfully synthesized by a simple one-pot hydrothermal method and used to build the immunosensor. The combination of SnS2 and SnO2 with matching energy levels promoted the layer-by-layer transfer of photogenerated charges, reduced the recombination efficiency of photogenerated electron, and enhanced the photoelectric conversion efficiency. Meanwhile, the addition of Zn ions introduced a trap level, which hindered the reduction of electrons, and the recombination of electron-hole pairs, improved the photocurrent response significantly. On the other hand, Au nanoparticles (NPs) were reduced in situ on the surface of Zn:SnO2/SnS2, thus anti-Aβ can form a gold amine bond with Au NPs. Therefore, Zn:SnO2/SnS2-Au could be a good substrate material for Aβ immunosensor, which provides a good basis for early detection of Alzheimer's disease. Under certain experimental conditions, the constructed PEC immunosensor exhibited a broad linear range from 0.1 pg·mL−1 to 100 ng·mL−1 with a detection limit as low as 0.05 pg·mL−1 (S/N = 3). It is worth mentioning that...
Source: Sensors and Actuators B: Chemical - Category: Chemistry Source Type: research