Research On Photoelectrochemical Biosensor Based On Cs_xWO₃ Heterogeneous Composites

Malignant tumors?cancers?have become a recognized major public health safety issue worldwide that seriously threatens human life,health and safety.According to the statistics of the National Cancer Center of China in 2019,the death of malignant tumors has become an important cause of death for residents,and the mortality rate of malignant tumors has increased in the past decade.However,more than 80%of early cancers can be suppressed or cured.Therefore,early detection and early treatment of cancer is particularly important for cancer patients.The photoelectrochemical?PEC?biosensor has both the advantages of fluorescence detection and electrochemical detection,making it a fast and sensitive method for detecting cancer markers.The PEC biosensor can separate the excitation signal and the detection signal,which can greatly reduce the background noise and achieve ultra-sensitive detection,and has the advantages of good selectivity,low cost and short response time.Cs_xWO₃ is a narrow band gap semiconductor material with good photoelectric response capability,low toxicity,low preparation cost and good environmental stability,and has good potential in photoelectrochemical biological applications.The heterostructure film is a special composite material that can adjust the spectral absorption range and has excellent coupling ability.It can promote the transfer of charge and thereby enhance the photocurrent response.Therefore,the performance of the PEC biosensor can be greatly improved.In this work,a photoelectrochemical biosensor based on Au/Cs_xWO₃ heterogeneous film for label-free detection of alpha-fetoprotein can be used,which can utilize the surface plasmon resonance capability of precious metals and the excellent photoelectric performance of Cs_xWO₃to achieve the purpose of enhancing photoelectric response,so that a photoelectrochemical biosensor with simple preparation,high sensitivity,relatively wide linear range,long-term stability and repeatability is obtained.The main work of this article is as follows:?1?Firstly,the Au film and Cs_xWO₃ nanocrystals were prepared by template method and colloid method,and their absorption performance,surface morphology and phase composition were characterized and analyzed.Then,Au/Cs_xWO₃heterogeneous thin film was prepared by spin coating.The structural morphology and photoelectric performance were analyzed.?2?PEC biosensors were prepared by modifying various biomolecules on the basis of the electrodes prepared above,analyzing each step of the modification,and optimizing the detection conditions.Under xenon light irradiation,the PEC biosensor achieved high sensitivity and good selectivity for tumor biomarker alpha-fetoprotein,the linear range of detection was 0.01ng/mL-500ng/mL,and the detection limit was as low as 7pg/mL.At the same time,the alpha-fetoprotein added to the human serum sample was detected,The relative standard?RSD?value was less than 6%,and the analytical recovery range was 97-104%.This indicates that the PEC biosensor prepared in this work is more accurate and has clinical application prospects.