A molecular imprinting photoelectrochemical sensor modified by polymer brushes and its detection for BSA

Polydopamine (PDA)-based molecular imprinting photoelectrochemical (MIP-PEC) sensor is usually applied to recognize proteins. However, the abundant active functional groups on the PDA surface lead to a non-specific adsorption at the non-imprinted sites, resulting in a decrease in the ability of the MIP-PEC sensor to qualitatively analyze proteins. To solve this problem, in the present work, the polymer brush is specially designed to been grafted onto the PDA imprinted layer of the Si-based photoelectrode and then reduces the probability of non-specific adsorption, improving the specific detection ability. In addition, the Si-based photoelectrode was formed by successively modifying buried junction, nitrogen-doped carbon and TiO2 on the Si wafer with micropyramid structure, enhancing the photocurrent density of the photoelectrode and improving the detection sensitivity. The experimental results suggest that the specific recognition ability of the MIP-PEC sensor to BSA was significantly improved with an increase of imprinting factor from 5.10 to 7.06. Also, the sensing signals showed a good linearity with BSA concentration in a range of 10-16-10-9 mg·mL−1, and a limit of detection of 2.203 × 10-17 mg·mL−1 (S/N = 3). Furthermore, it was also successful to analysis as the template of acetylcholine was used, confirming the universality of this method.