Photoelectrochemical Bioensor Constructed By Metallic Oxide Semiconductor

Various diseases in the human body threaten human health and life,so it is essential to detect diseases.Photoelectrochemical biosensors can play an important role in disease detection.The detection principle is to use biomarkers in the human body as excitation signals,and use the sensors to convert the undetectable biological signals into quantifiable current signals which are easy to observe and output to a specific instrument.Based on the principle,biosensors are used to sensitively track and detect biomarkers related to various diseases in the human body.Two of the most important factors which observably affect sensor performance are the target recognition strategy and the signal amplification strategy.The fast and sensitive recognition strategy and the effective signal amplification strategy are conducive to improving the detection performance of the sensor.In the photoelectric sensor,the photoelectric active material is inseparable from the photoelectric conversion performance of the sensor.The metal oxide semiconductor material is an excellent photoelectric active material,which has the advantages of high stability,simple synthesis method,and high photoelectric conversion efficiency.Based on these properties,metal oxide semiconductors have great application value in the construction of photoelectrochemical biosensors.In this paper,based on the excellent performance of metal oxide semiconductor materials in photoelectric conversion,photoelectrochemical biosensors were constructed combined with effective target recognition strategy and signal amplification strategy to sensitive detect prostate specific antigen and cancer marker?miRNA?.The specific work is as follows:?1?Anodized titanium dioxide was etched and calcined on the titanium sheet by anodizing method.CdTe quantum dots are loaded on the surface of titanium dioxide nanotubes by layer-by-layer assembly to form a sensitized structure and enhance the photoelectric conversion efficiency of the electrode.Subsequently,a peptide chain of a specific sequence is fixed on the electrode surface and double-stranded DNA is loaded on the end of the peptide chain.The double-stranded DNA is further loaded with CuS nanoparticles.Based on the principle that the peptide chain is cut by the antigen in the presence of prostate-specific antigen,the loading of CuS nanoparticles on the electrode surface is adjusted to produce a change in photocurrent,and a photoelectrochemical organism with a sensitive response to prostate-specific antigen is constructed accordingly sensor.?2?Mesoporous hollow titanium dioxide nanospheres were synthesized by hydrothermal method and fixed to the surface of the ITO electrode,and then a layer of bismuth sulfide was loaded on the electrode surface to form a heterojunction structure to improve the photoelectric performance.The surface-immobilized DNA then captures the Co₃O₄-Au polyhedron as a signal quencher.Co₃O₄-Au polyhedron can not only consume electron donor and light energy,but also catalyze the production of insoluble precipitates.A cascade of enzyme-assisted circulation strategies is used to cleave the DNA on the electrode surface,affect the loading of Co₃O₄-Au polyhedron,realize photoelectric signal amplification,and build a photoelectrochemical biosensor for detecting mi RNA.