Using reduced graphene oxide-Ca:CdSe nanocomposite to enhance photoelectrochemical activity of gold nanoparticles functionalized tungsten oxide for highly sensitive prostate specific antigen detection.

Author(s) Wang, X.; Xu, R.; Sun, X.; Wang, Y.; Ren, X.; Du, B.; Wu, D.; Wei, Q.
Journal Biosens Bioelectron
Date Published 2017 Oct 15

An ultrasensitive sandwich-type photoelectrochemical (PEC) immunosensor was constructed for the detection of prostate specific antigen (PSA). In this work, Au-nanoparticle-loaded tungsten oxide (WO3-Au) hybrid composites was applied as PEC sensing platform, while Ca ions doped CdSe equipped on the conducting framework of reduced graphene oxide (rGO-Ca:CdSe) nanocomposites were employed as the signal amplification probe. As for WO3-Au, massive Au nanoparticles were formed on the surface of WO3 without any additional reducing agent, providing a novel nanocarriers for anchoring plenty of the primary antibodies due to the large specific surface area and good biocompatibility by chemical bonding between Au nanoparticles and -NH2 of antibodies. Besides, the incorporation of the rGO and the doping of Ca ions could improve the conductivity and hinder the recombination of electron-hole pairs of CdSe nanoparticles effectively, thereby enhancing the photocurrent conversion efficiency. Based on the sandwich immunoreaction, the primary antibody was immobilized onto WO3-Au substrate, after the formed rGO-Ca:CdSe labels were captured onto the electrode surface via the specific antibody-antigen interaction, the photocurrent intensity could be further enhanced due to the sensitization effect. Under the optimal conditions, the proposed PEC immunosensor shows a linear relationship between photocurrent variation and the logarithm of PSA concentration in the wide range of 5pgmL(-1) to 50ngmL(-1) with a low detection limit of 2.6pgmL(-1) (S/N=3). Moreover, it also presented good stability and acceptable specificity, indicating the potential applications in clinical diagnostics.

DOI 10.1016/j.bios.2017.04.052
ISSN 1873-4235
Citation Biosens Bioelectron. 2017;96:239245.

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