Study On The Application Of Fluorescence Biosensor Based On Nucleic Acid Aptamer In Bisphenol A Detection

With the rapid development of industry and economy,a large number of toxic and harmful pollutants are discharged into the natural environment,leading to environmental pollution problems become increasingly prominent.Therefore,it is of great significance to explore the development of new,sensitive and reliable detection methods to monitor environmental pollutants.Fluorescence biosensor detection technology is widely used in environmental monitoring and environmental analysis chemistry with its high sensitivity and good selectivity.A new series of fluorescent biosensor methods were constructed based on nucleic acid aptamers and novel nanomaterials and applied to the detection of bisphenol A in environmental water.The main contents of this paper are as follows:(1)Based on the fluorescence resonance energy transfer between the magnetic oxidized graphene and the fluorescein labeled on the BPA aptamer,a magnetic separation "turu-on" fluorescence biosensor was constructed to detect BPA.The BPA aptamer is labeled with fluorescein.When BPA is absent,the magnetic oxide graphene can adsorb the fluorescein-labeled BPA aptamer to form an aptamer-magnetic graphene oxide compound(Aptamer-MGO),due to fluorescence resonance energy transfer,the magnetic oxide graphene can effectively quench the fluorescence of fluorescein labeled on the BPA aptamer.When the target BPA is present,the fluorescein-labeled BPA aptamer preferentially binds to the target BPA to switch spatial conformation of aptamer so that the fluorescein-labeled BPA aptamer are desorbed from the surface of the magnetic graphene oxide,and after magnetic separation,the fluorescence of the fluorescein is restored.The fluorescence intensity of the reaction system is related to the concentration of BPA,and the fluorescence intensity of the reaction system increases with the increase of BPA concentration.The fluorescent biosensor has strong specificity and high selectivity for the target BPA,and it also has strong anti-interference ability and high sensitivity.(Chapter 2)(2)A new method for the detection of BPA by unlabeled time-resolved fluorescence analysis was developed based on unlabeled BPA aptamers,unlabeled terbium complexes and unlabeled gold nanoparticles.When BPA is present,the BPA aptamers are adsorbed onto the surface of the gold nanoparticles so that the gold nanoparticles remain stable in the high concentration of sodium chloride solution and do not agglomerate.When the terbium complex was added to the reaction system,the well-dispersed gold nanoparticles effectively quench the fluorescence of the terbium complex.When BPA is present in the reaction system,the BPA aptamers preferentially combine with BPA to form a specific three-dimensional space structure,and the gold Nanoparticles can not adsorb BPA aptamers that have formed a specific three-dimensional structure.When adding a high concentration of sodium chloride solution,the gold nanoparticles are agglomerated without the protection of BPA aptamer.After centrifugation,the agglomerated gold nanoparticles in the reaction system are removed.When the terbium complex is added,the quenching efficiency of the terbium complex is reduced,and the fluorescence signal of the reaction system is enhanced.The detection method has good selectivity and high sensitivity.(Chapter 3)...