Study On Preparation And Application Of Photoelectrochemical Biosensor

The analytical method of photoelectrochemical biosensor was developed on the basisof the bioelectrochemical sensors. Through combining photoelectrosensitive interfaceand various films of bio-sensitivity can develop more types of photoelectrochemicalbiosensors. In this paper, the enzyme was immobilized on the poly（thionine）photoelectrochemical interface with photosensitive and electron receptor. Thehydrogen peroxide （H₂O₂） proceed from enzyme-catalyzed react with poly（thionine） togenerate the photoelectrochemical effect. Accordingly, the substrate can be determinedthrough monitoring the photocurrent.The main works are shown as follows:1. The photoelectrode was fabricated by electropolymerizing thionine on the surface ofITO electrode. By detecting the photocurrent generated by the photoelectrochemicalreaction between the poly（thionine） and H₂O₂, detection of the concentration of H₂O₂.In the paper, the photoelectrochemical reaction mechanism of poly（thionine） to H₂O₂was described. The photoelectrochemical effects of photoelectrode to H₂O₂werestudied. Effects of bias voltage and electrolyte pH on the photocurrent wereinvestigated.2. A new photoelectrochemical biosensing platform for uric acid was fabricated basedon a photoelectric interface. The photoelectrochemical response of biosensor to H₂O₂and the paper realize uric acid concentration detection. In the paper, thephotoelectrochemical reaction mechanism of poly（thionine） to H₂O₂was described.Experiments the effect of enzyme concentration, the coating fluid volume,concentration of chitosan and pH to the photocurrent. The linear response of uric acidconcentrations ranged from2.00¹0.0×10^-6mol L^-1and6.00¹00×10^-5mol L^-1wasobtained with a detection limit of0.80μmol L^-1.3. The first use of structrual similarity, xanthine oxidase catalyzed guanine weremeasured, prepare a new type of photoelectrochemical guanine biosensor. thephotoelectrochemical reaction mechanism was described. Effects of the coating fluid volume， bias voltage and electrolyte pH on the photocurrent were investigated. Thelinear response of guanine concentrations ranged from1.00×10^-62.00×10-4mol L^-1was obtained with a detection limit of1.67×10^-7mol L^-1.4. A new photoelectrochemical sensor was prepared to detect the acid hydrolysis timeon the extent of DNA damage. The experimental data show that: with the increase ofacid hydrolysis time, photocurrent response becomes larger, the injury rate was0.912.The potocurrent is well-proportional to the concentration of DNA over the rang from0.90⁶0.0μg ml^-1, with a detection limit of3.0μg ml^-1.