G-四链体二聚体/核酸外切酶Ⅰ辅助信号放大纸芯片检测黄曲霉毒素B1OA北大核心CSTPCD

In this work,a tetrahedral DNA nanostructure(TDN)functionalized rotational paper-based analytical device(RPAD)was constructed for rapid and highly sensitive detection of aflatoxin B1(AFB1)using exonucleaseⅠ(ExoⅠ)and G-quadruplex(G4)dimer.Herein,a single-stranded DNA,containing both of the G4 dimer sequence and AFB1 recognition sequence,was used as the recognition probe(G4 dimer probe).TDN was used to precisely regulate the orientation and distribution density of G4 dimer probe to improve the recognition efficiency of the system.ExoⅠas a single stranded DNA specific nuclease was introduced for effective amplification of the detection signal.G4 dimer was employed to enhance the fluorescence signal of thioflavin T(ThT).In the absence of AFB1,the G4 dimer structure of G4 dimer probe could specifically bind with ThT to generate dramatic fluorescence enhancement.However,in the presence of AFB1,AFB1 could specifically bind with G4 dimer probe,resulting in the dissociation of G4 dimer probe from TDN and further be digested by ExoⅠ.At the same time,the released AFB1 could bind to G4 dimer probe on the TDN again by this way to generate signal amplification.After this cycle,the amount of aptamer on the TDN was decreased,accompanied by the reduction of G4 dimer on TDN.In this case,the fluorescence intensity of the system was reduced.The designed RPAD showed a good linear response in AFB1 concentration range of 0.0001-500 ng/mL and the limit of detection was 0.1 pg/mL.Moreover,the proposed strategy was successfully applied to detection of AFB1 in peanut and wine.The developed TDN/G4 dimer/ExoⅠstrategy improved the specificity and sensitivity of the system significantly.