摘要
A novel magnetic controlled photoelectrochemical (PEC) sensing system was designed for sensitive detection of prostate-specific antigen (PSA) using reduced graphene oxide-functionalized BiFeO 3 (rGO-BiFeO 3 ) as the photoactive material and target-triggered hybridization chain reaction (HCR) for signal amplification . Remarkably enhanced PEC performance could be obtained by using rGO-BiFeO 3 as the photoelectrode material due to its accelerated charge transfer and improved the visible light absorption. Additionally, efficient and simple operation could be achieved by introducing magnetic controlled flow-through device. The assay mainly involved in anchor DNA-conjugated magnetic bead (MB-aDNA), PSA aptamer/trigger DNA (Apt-tDNA) and two glucose oxidase-labeled hairpins (H1-GOx and H2-GOx). Upon addition of target PSA, the analyte initially reacted with the aptamer to release the trigger DNA , which partially hybridized with the anchor DNA on the MB. Thereafter, the unpaired trigger DNA on the MB opened the hairpin DNA structures in sequence and propagated a chain reaction of hybridization events between two alternating hairpins to form a long nicked double-helix with numerous GOx enzymes on it. Subsequently, the enzymatic product (H 2 O 2 ) generated and consumed the photo-excited electrons from rGO-BiFeO 3 under visible light irradiation to enhance the photocurrent . Under optimal conditions, the magnetic controlled PEC sensing system exhibited good photocurrent responses toward target PSA within the linear range of 0.001 − 100 ng/mL with a detection limit of 0.31 pg/mL. Moreover, favorable selectivity, good stability and satisfactory accuracy were obtained. The excellent analytical performance suggested that the rGO-BiFeO 3 -based PEC sensing platform could be a promising tool for sensitive, efficient and low cost detection of PSA in disease diagnostics.
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