Novel Aptamer-based Electrochemical Sensors For ATP And Kanamycin

In recent years,aptamer sensors have been used in more and more research and detection due to their advantages of high specificity,high sensitivity and economic convenience.In this paper,electrochemical sensors based on nucleic acid aptamers were applied to the detection of ATP and Kan,and two different electrochemical sensors of nucleic acid aptamers were constructed,which realized the rapid and highly sensitive detection of target substances.The second part of this thesis,we report a convenient and highly sensitive sandwich electrochemical sensor based on a new conception of bivalent split aptamer signal probe.The sensor is designed by simple hybridization of two identical split aptamers and DNA scaffold chain,which makes the detection convenient and sensitive.As the bivalent synergistic effect enhances the binding ability of target molecules,the signal gain of the bivalent signal probe based on DNA-scaffolded is significantly increased compared with the traditional monovalent signal probe.Through rational optimization of the length of anchor duplex in DNA scaffold and concentration of bivalent signal probe in electrochemical test solution,high signal sensitivity for ATP detection is achieved.The detection range was 0.1μM~200μM,the linear equation was:SI/%=15.99×[ATP/μM]+59.89,R~2=0.9988,and the detection limit is 41 nM.The DNA-scaffolded bivalent signal probe based sandwich electrochemical sensor is also specifific,selective and applicable for ATP detection in real samples.Due to its simplicity in design and high sensitivity for target recognition,the conception of DNA-scaffolded bivalent signal probe will provide a useful guide to further developing split aptamer-based sandwich electrochemical sensors for a wide variety of other target analytes.In the third part of this paper,a hairpin electrochemical sensor based on monovalent aptamer signal probe is designed to detect Kan.The sensor applied the principle that the conformational change of labeled monovalent aptamer probe on the gold electrode caused the change of electrical signal to kanamycin detection.Buffer solution for electrochemical test,the concentration of the aptamer fixed on the electrode,detection frequencywere optimized,a rapid and simple electrochemical detection method of kanamycin was established.The sensor has high specificity and selectivity,the detection range is 0.05~10μM,the linear equation is SI/%=4.063×[Kan]/Μm+6.600,R~2=0.997,the recovery rate is high,can be used in the detection of actual samples.