Zhang Q(1), Liu X(1), Wang H(1), Liu Q(1), Liu Q(1), Zhang X(2). Author information:
(1)College of Chemical and Biological Engineering; State Key Laboratory of
Mining Disaster Prevention and Control Co-founded by Shandong Province and the
Ministry of Science and Technology, Shandong University of Science and
Technology, Qingdao 266590, China. [Email]
(2)Shandong Provincial Key Laboratory/Collaborative Innovation Center of
Chemical Energy Storage & Novel Cell Technology; College of Chemical and
Chemical Engineering, Liaocheng University, Liaocheng 252059, China.
In this work, a thrombin photoelectrochemical aptasensor was reported based on a photoanode of perylene-3,4,9,10-tetracarboxylic acid (PTCA), Au nanoparticle co-functionalized ZnO nanorods (ZnO NRs) and the "signal-off" amplification effect of Ag@Ag2S. The photocurrent response of the ZnO NRs was improved greatly due to the excellent visible-light photoelectric performance of PTCA and the surface plasmon resonance (SPR) effect of Au nanoparticles. Due to the specific recognition between thrombin and aptamers, the non-conductive complex with a steric hindrance structure blocked the diffusion path of the electron donating ascorbic acid (AA) and then the "signal-off" Ag@Ag2S quencher was captured. The quencher blocked the irradiation light toward the ZnO NRs/PTCA/Au electrode and competitively consumed the electron donor AA that could have been involved in the oxidation reaction with photogenerated holes of PTCA, resulting in the further decrease of the photocurrent. Based on the evident photocurrent response of the photoanode and the superior quenching strategies, the detection limit of thrombin is as low as 33 fM with a wide linear detection range from 0.0001 nM to 50 nM. The prepared biosensor also exhibited good specificity, reproducibility and stability, suggesting potential application in thrombin specific detection.
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