Design And Construction Of Photoelectrochemical Immunosensors Based On Zinc Oxide Nanomaterials

Photoelectrochemical(PEC) measurements are a newly emerging and dynamically developing technique with high sensitivity, in which light as excitation source and photocurrent as detection signal. In PEC measurements, one important aspect is to find highly efficient and biocompatible photoactive materials to transform the light input into current output. As a PEC active material, zinc oxide(ZnO) has attracted much attention due to its suitable band gaps and high photoelectric and photocatalytic activities. In particular, ZnO nanomaterials exhibit a few distinct advantages, including good carrier mobility, simple tailoring of the structures, facile and low-cost for large-scale manufacturing.In this paper, we prepare ZnO-based PEC immunosesnors for various antigens detection.1. ZnO nanoflakes with a large surface area are electrodeposited onto a gold-paper electrode, and then functionalized with CuS via a simple hydrothermal and ion exchange method. As an excellent photoactive material, CuS is used to construct PEC immunosensor for the first time. The proposed method achieves sensitive carcinoembryonic antigen detection based on an in situ electron donor producing approach.2. ZnO nanorods are grown on gold nanoparticles modified paper working electrode via a simple and low temperature hydrothermal method, then attaches the tetra-carboxyl naphthalocyanine zinc onto ZnO surface. By combining fast electron transportation rate of ZnO nanorods and intense absorption of tetra-carboxyl naphthalocyanine zinc in the near IR region, the proposed PEC immunosensor exhibit high sensitivity for detection of carcinoembryonic antigen.3. A chemiluminescence(CL) excited PEC competitive immunosensor for sensitive and specific detection of the prostate specific antigen is developed. The combination of CL emission and the competitive strategy realize low-cost and time efficient immunosensing. Porous ZnO spheres with large surface area and good biocompatibility are served as an effective matrix for antigens. CdS nanorods are selected as the photoactive materials due to their excellent electron transport capability. The proposed immunosensor shows excellent analytical performance with high reproducibility and stability.4. Multiplexed PEC immunoassays are introduced into an indium tin oxide(ITO) device. AuPd alloy nanoparticles are electro-deposited on ITO working electrodes as electron sink, and then, ZnO nanotubes(ZNTs) arrays are synthesized via chemical etching of ZnO nanorods that are electrochemically pre-deposited on AuPd surface. ZNTs with high surface area provide much more multidimensional spaces for loading more CdS. Excellent analytical performance of the immunosensor is attributed to the synergistic effect between AuPd alloy nanoparticles, ZNTs and CdS. As a signal label, CuO can change the transfer path of electron-hole pairs in CdS, and consequently amplify the PEC signal for the first time. The proposed PEC immunosensors for tumor markers show wide liner range and low detection. The high sensitivity, specificity and reproducibility of the method permit the method suitable to be used in real samples.