Preparation Of Copper-based Oxide Photocathode Nanomaterials And Detection Of Disease Markers

Photocathode sensors inherit the advantages of high sensitivity,low cost,and simple devices of photoelectrochemical biosensors,and have stronger resistance to interference with reducing substances and stability than photoanode sensors.Therefore,the exploitation of photocathode sensors is of great significance for the early diagnosis of diseases.It is proposed to prepare photocathodes based on naturally abundant,biocompatible and morphologically diverse,and controllable cuprous oxide.In the implementation of photoelectrochemical tests,however,the application of single cuprous oxide is limited due to its susceptibility to photocorrosion and carrier compounding.Therefore,in Work I,the cuprous oxide was first modified by modulating the microscopic morphology,controlling the particle size,and constructing heterojunctions.It was used to prepare a photocathode sensor for detecting alkaline phosphatase（ALP）.To improve the problems fed back from work I.In Work II,the performance of the photocathode was further enhanced by improving the electrode preparation method and introducing self-powering.The photo-assisted-bipolar self-powered cathode sensor was constructed by combining different signal amplification mechanisms to achieve highly selective and sensitive detection of cardiac troponin I（c Tn I）.The details of the work are as follows:（1）A photocathode sensor based on Cu₂O@Cu@Ui O-66-NH₂ nanocubes coupled with hollow Co₃O₄/C（hsCo₃O₄/C）multi-signal amplifier and target-modulated occupancy effect was constructed.Ui O-66-NH₂ with refined molecular recognition function forms a heterojunction with Cu₂O to increase the photoelectric signal and visible light absorption range.Moreover,the Zr ions on the surface of Ui O-66-NH₂ provide sufficient competition sites for the ss DNA-coupled multi-signal amplifier hsCo₃O₄/C and trimeric phosphate（STPP）.ALP plays a decisive regulatory role in the process of competition between STPP and ss DNA.Eventually,the sensor was able to quantify ALP in the range of 0.0244～100 U/L with the aid of the multi-signal amplifier hsCo₃O₄/C in a"signal-off"mode,with a detection limit of 0.009U/L（S/N=3）.It has a competitive edge in the field of ALP detection.20（2）A photo-assisted-bipolar self-powered photocathode sensor with excellent photovoltaic performance was constructed by combining a homogeneous nanorod-like photocathode CF-350 grown in situ on copper foam with an FTO/CdS-1 photoanode.The photocathode signal was enhanced by the synergistic effect of heterojunction and self-energy supply,thus increasing the detection signal window and eliminating the dependence on the external bias.The parallel placement of CF-350 and FTO/CdS-1 photoelectrodes can effectively capture more incident light sources,and the nanorod-like CF-350 as a working electrode provides sufficient active sites for target loading.The sensing platform was finally combined with a Cu-BTC signal amplifier to achieve sensitive detection of c Tn I in the range of 1×10^-2～1×10³ ng/m L in a"signal-off"mode with a detection limit of 0.0037 ng/m L（S/N=3）.