Study And Application Of Novel Aptamer Probe For Detecting Biphenol A

Endocrine-disrupting chemicals(EDCs) are some artificial or naturalchemical substances, which can interfere with the function of the endocrine system,and then cause adverse effects of the organic organisms. Bisphenol A(BPA), one ofthe environmental endocrine disruptors, is a kind of organic chemical raw material ofindustrial synthesis of polycarbonate, epoxy resins, polysulfone resins, polyphenyleneether resin, unsaturated polyester resins and other polymer materials. BPA not onlycan destroy the potential role of thyroid hormone, but also can cause the proliferationof human prostate cancer cells, so much as impeding the synthesis of testosterone atlow dose. Currently, detections of BPA are mainly mass spectrometry, fluorescence,and ultraviolet spectrophotometry, and so on. In this paper, BPA was first detected byaptamer-based biosensors based on specific binding between BPA and BPA aptamer.In chapter1, the mechanism of action and prevention of environmental hormones,and the hazards and detections of BPA were described. We also introduced aptamerand systematic evolution of ligands by exponential enrichment(SELEX).In chapter2, we developed a novel aptamer sensor for detecting BPA byfluorescence resonance energy transfer(FRET). We used two complementary chainsof BPA aptamer with two fluorophores,6-carboxytetramethylrhodamine(6-TAMRA)and6-carboxyfluorescein (6-FAM), respectively, as oligonucleotide probes, whichhybridize with BPA aptamer. The introduction of BPA lead to fluorescence resonanceenergy transfer, resulting in the fluorescence intensity changes. The relationshipbetween BPA concentration and the change of the fluorescence intensity was gotten.In chapter3, we developed a novel aptamer sensor for detecting BPA byelectrogenerate chemilumnescence(ECL). The complementary chain of BPA aptamerwith Ru(bpy)32+-SiO2NPs at the termini of the oligonucleotide was self-assembled ongold electrode surface. While hybridizing BPA aptamer, the Ru(bpy)32+-SiO2NPs wasfar away from the gold electrode surface and ECL signal was reduced. Theintroduction of BPA removed aptamer, leading to ECL signal increases. It can beindirectly measured the concentration of BPA by the variation of the ECL signal.In chapter4, we developed a novel aptamer sensor for detecting BPA byelectrochemical impedance spectroscopy(EIS). Since the surface structure of dsDNAis more orderly and more stable than the ssDNA, and has more negative charge, hence,the charge transfer of [Fe(CN)6]3-/4-is hindered greater. Therefore, the impedance ofthe gold electrode modified dsDNA is greater. The introduction of BPA removedaptamer, leading to impedance reduces. It can be indirectly measured the relationshipbetween BPA concentration and the variation of the impedance.