Key Laboratory of Interfacial Reaction & Sensing Analysis in Universities of Shandong, School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, P. R. China.
J Mater Chem B. 2019 Feb 21;7(7):1142-1148. doi: 10.1039/c8tb03164a. Epub 2019 Jan 30.
In this work, the heterostructures of Au nanoparticles loaded on 3D flower-like α-FeO (Au NPs/α-FeO) as a platform and core-shell CdSe@CdS quantum dots sensitized graphene oxide (GO/CdSe@CdS QDs) as a signal amplification label were established in an ultrasensitive sandwich-type photoelectrochemical (PEC) immunosensor based on the "signal-on" type amplification method for detection of amyloid β-protein (Aβ). Specifically, the ultrahigh sensitivity of the proposed immunosensor came from two main properties. First, Au NPs/α-FeO could partially absorb visible-light, which dramatically promotes electron transfer because of the excellent conductivity of Au NPs, and effectively inhibits the electron-hole recombination, thanks to the effect of heterostructures. Second, the signal-on type is based on the signal amplification label of GO/CdSe@CdS QDs which on adequate absorption of visible-light can improve generation of photogenerated electron-hole pairs effectively. Under optimal conditions, the well-prepared PEC immunosensor exhibited a low detection limit of 0.02 pg mL and a wide linear range from 0.06 pg mL to 350 ng mL for Aβ detection. Meanwhile, it also presented good reproducibility, specificity, and stability and might open a new promising pathway for detection of other important biomarkers.
在这项工作中，以 3D 花状 α-FeO 负载的 Au 纳米粒子（Au NPs/α-FeO）作为平台，以核壳型 CdSe@CdS 量子点敏化的氧化石墨烯（GO/CdSe@CdS QDs）作为信号放大标记物，建立了一种基于“信号开启”型放大方法的超灵敏夹心型光电化学（PEC）免疫传感器，用于检测淀粉样β蛋白（Aβ）。具体来说，所提出的免疫传感器的超高灵敏度来自两个主要特性。首先，Au NPs/α-FeO 可以部分吸收可见光，由于 Au NPs 的优异导电性，这极大地促进了电子转移，并由于异质结构的作用，有效地抑制了电子-空穴复合。其次，基于 GO/CdSe@CdS QDs 的信号放大标记物采用信号开启型，其在充分吸收可见光后，能够有效地提高光生电子-空穴对的产生效率。在最佳条件下，所制备的 PEC 免疫传感器对 Aβ检测的检测限低至 0.02 pg mL，线性范围从 0.06 pg mL 到 350 ng mL。同时，它还表现出良好的重现性、特异性和稳定性，为检测其他重要生物标志物开辟了一条新的有前途的途径。
