Application Of Aptamer-based Fluorescence Sensing Technology In Environmental Analysis

Chapter 1: Firstly,the definition,characteristics,screening technology in vitro and application of aptamer are introduced,and then bisphenol A,kanamycin,cocaine and their detection methods are reviewed,respectively.Then the research developments of their aptamer-based sensors are summarized.Finally,the research background and the contents of this thesis are introduced.Chapter 2: Bisphenol A(BPA)is widely used in plastic products and metal products coatings and we are closely related to it.BPA is a kind of endocrine disruptors that has quasi-estrogenic effect,and it is seriously harmful to human body.In this chapter,berberine was used as the fluorescence probe,BPA and its aptamer can form G-quadruplex structure,which caused to release of berberine from the base pair of the aptamer.The analytical characteristics of two kinds of aptamers of BPA were studied,and the suitable aptamer was selected and then the selectivity of the presented method was investigated.The linear range of the system was 0 mM to 1300 mM,the detection limit was 32 n M(S/N=3),the recovery of BPA in the drinking water was in the range of 92.4 %-102.3 %,and this method can be applied in the actual samples for the detection of BPA.Chapter 3: Kanamycin can inhibit most bacteria reproduction and promote animal growth,and it has been widely used in clinical treatment and forage production,the abuse of kanamycin can cause a variety of resistant strains and hearing impairment.In this chapter,berberine was used as the fluorescence probe,kanamycin and its aptamer can form hairpin structure,which caused to release of berberine from the base pair of the aptamer.Various factors including the concentration of aptamer,p H effect and ion strength were investigated in detail.Under the optimal experimental conditions,The fluorescence intensity of the sensing system displayed a calibration response for kanamycin in the range of 5 nM to 70 nM with a detection limit of 2.3 n M(S/N=3),the recovery in the milk samples was in the range of 98.3 %-101.2 %,this method can be used in the actual samples for the detection of kanamycin.Chapter 4: Cocaine is one of the five recognized drugs in the world,and it has caused a series of social problems due to its abuse.As such,rapid,accurate and sensitive qualitative and quantitative analysis of cocaine is of great interest in the fields of chemistry and biotechnology.Based on its lower detection limit and higher sensitivity and selectivity,aptamer combined with fluorescence spectrometry has been widely applied in the fields of analysis and detection,in which appropriate fluorescence probe and aptamer play an important role.A simple,rapid and label-free fluorescent aptasensing platform was fabricated for the detection of cocaine in aqueous solution using cocaine-stabilized three oligonucleotide sequences as the recognition element and berberine as the fluorescence probe.Various factors including the concentration of aptamer,p H effect and ion strength were investigated in detail.Under the optimal experimental conditions,The fluorescence intensity of the sensing system displayed a calibration response for cocaine in the range of 5 mM to 100 mM with a detection limit of 2.8 mM(S/N=3).This label-free fluorescence aptasensor is conveniently and effectively applicable for analysis of cocaine in blood serum samples with the recovery range of95.6%-101.3%.