Highly Sensitive Voltammetric Thrombin Aptamer Sensor Based on the Synergistic Effect of Doping/Depositing Gold Nanoparticles in Polydopamine Film

A highly sensitive square-wave voltammetric thrombin (TB) aptamer sensor was developed using functional polydopamine (PD) film by doping and depositing gold nanoparticles into the bulk and the surface of PD. The aptamer sensor was fabricated by immobilizing a thiolated TB-binding aptamer (TBA) on the AuNPs-doped/deposited PD film. AuNPs-supported methylene blue labels were used for the detection of human alpha-TB. Under the optimized conditions, the aptamer sensor's dynamic range and the detection limit were determined to be 2.0 pM-50 nM and 0.97 +/- 0.06 pM, respectively. Finally, the proposed aptamer sensor was successfully examined in human serum samples and satisfactory results were obtained.