Research On Photoelectrochemical Sensor And Signal Amplification Strategy Based On Semiconductor Metallic Oxide

Major diseases bring physical and mental harm to people.As an analytical method to transform biomarkers signal into quantifiable photocurrent signal,photoelectrochemical biosensor is used for rapid tracking of various disease-related biomarkers with high sensitivity.The intensity of photocurrent signal is the key factor that influenced the sensitivity of photoelectrochemical biosensor,which is closely related to the photoelectric properties of photoactive materials.Semiconductor metal oxide materials,as the photoactive material with good photoelectric properties,are widely employed to construct sensitive photoelectrochemical biosensors due to its fascinating merits,such as moderate absorption coefficient,short charge carrier lifetime,simple preparation,large specific surface area,and high chemical stability.In this paper,according to the sensitive signal response of various biomarkers,the highly sensitive photoelectrochemical biosensor was constructed by combining the excellent photoelectric properties of semiconductor metal oxide materials and the efficient signal amplification strategy in the biometric process.The main research work is as follows:(1)The paper fibers were first functionalized with titanium dioxide nanosheets by hydrothermal method to increase the conductivity of paper chips.Then high-performance heterostructure was obtained by loading cerium dioxide nanoparticles on the surface of titanium dioxide with the aid of hairpin probe.Based on the hybridization of hairpin probe with the DNA probe resulted from the nicking enzyme signaling amplification strategy,the distance between titanium dioxide and cerium dioxide could be regulated,resulting in the change of photocurrent signal.Therefore,the photoelectrochemical biosensor for sensitive detection of thrombin was constructed.(2)The photocurrent signal was enhanced by integrating the heterostructure enhancement strategy with the branched titanium dioxide nanorods synthesized by hydrothermal method.The synthesized strontium titanate/branched titanium dioxide nanorods heterostructure exhibited excellent photoelectric properties and was first used for the construction of photoelectrochemical biosensors.The specific enzyme of ?-galactosidase and acetylcholinesterase were used to label the two different target signal antibodies respectively.Based on the specific enzyme-catalyzed reactions and the recognition between antigen and antibody,the signal amplification was realized and the photoelectrochemical biosensor for the simultaneous analysis of alpha fetoprotein and cancer antigen 153 was constructed.(3)Three-dimensional titanium dioxide nanosheets network with high surface area were synthesized on the surface of FTO by hydrothermal method,which provided plentiful active sites for the deposition of cadmium sulfide quantum dots.The resulted quantum dot sensitization effect could availably enhance the photocurrent signal.Upon the specific recognition between the target prostate specific antigen and its aptamers,the copper nanoclusters were forced to separate from target aptamer.After pickling,the separated DNA-copper nanoclusters produced multiple copper ions,achieving the signal amplification.Based on the reaction between the copper ion and cadmium sulfide quantum dots,the photocurrent intensity was inhibited,and the photoelectrochemical biosensor was constructed for the sensitive analysis of prostate specific antigen.