Reduced graphene oxide-functionalized FeOOH for signal-on photoelectrochemical sensing of prostate-specific antigen with bioresponsive controlled release system

A new and signal-on photoelectrochemical (PEC) sensing platform was successfully designed for the sensitive detection of prostate-specific antigen (PSA), using reduced graphene oxide- functionalized iron oxyhydroxide (FeOOH-rGO) as the photoactive material, accompanying target-responsive controlled release system to achieve the signal amplification. Introduction of rGO as electron mediator greatly facilitated the electron transfer from FeOOH to electrode under visible light, which inhibited the electron-hole recombination to enhance the photo-activity of FeOOH-rGO. Additionally, the bioresponsive release system was controlled via the reaction of target PSA with the aptamer capped glucose-loading mesoporous silica nanoparticle (MSN) to release numerous glucose molecules (as the electron donors) for the amplification of the photocurrent generated from FeOOH-rGO. Thus, more glucose molecules could be released and enhanced photocurrents could be obtained with the increasing PSA concentrations. Experimental results showed that the photocurrents of the PEC sensing platform were linearly dependent on the logarithm of PSA concentrations from 1.0 pg/mL to 100 ng/mL. Moreover, the PEC sensing system afforded good stability and specificity, and its accuracy matched well with the commercial PSA enzyme-linked immunosorbent assay (ELISA) kit. The excellent performance of the PEC sensing platform indicated its promising prospect as a useful tool for PSA detection in practical application.