A Label-Free Colorimetric Aptasensor Containing DNA Triplex Molecular Switch and AuNP Nanozyme for Highly Sensitive Detection of Saxitoxin  

作　　者：QI Xiaoyan LI Ling YAN Xiaochen ZHAO Yinglin WANG Lele MA Rui WANG Sai MAO Xiangzhao 

机构地区：[1]College of Food Science and Engineering,Ocean University of China,Qingdao 266003,China [2]Laboratory for Marine Drugs and Bioproducts of Qingdao National Laboratory for Marine Science and Technology,Qingdao 266237,China

出　　处：《Journal of Ocean University of China》2022年第5期1343-1350,共8页中国海洋大学学报（英文版）

基　　金：funded by the National Natural Science Foundation of China(No.31801620).

摘　　要：Saxitoxin(STX),one of the most toxic paralytic shellfish poisons discovered to date,is listed as a required item of aquatic product safety inspection worldwide.However,conventional detection methods for STX are limited by various issues,such as low sensitivity,complicated operations,and ethical considerations.In this study,an aptamer-triplex molecular switch(APT-TMS)and gold nanoparticle(AuNP)nanozyme were combined to develop a label-free colorimetric aptasensor for the rapid and highly sensitive de-tection of STX.An anti-STX aptamer designed with pyrimidine arms and a purine chain was fabricated to form an APT-TMS.Specific binding between the aptamer and STX triggered the opening of the switch,which causes the purine chains to adsorb onto the surface of the AuNPs and enhances the peroxidase-like activity of the AuNP nanozyme toward 3,3’,5,5’-tetramethylbenzidine.Under optimized conditions,the proposed aptasensor showed high sensitivity and selectivity for STX,with a limit of detection of 335.6 pmol L^(−1) and a linear range of 0.59-150 nmol L^(−1).Moreover,good recoveries of 82.70%-92.66%for shellfish and 88.97%-106.5%for seawater were obtained.The analysis could be completed within 1 h.The proposed design also offers a robust strategy to achieve detection of other marine toxin targets by altering the corresponding aptamers.

关 键 词：SAXITOXIN colorimetric aptasensor APTAMER triplex molecular switch AuNP nanozyme 

分 类 号：TS254.7[轻工技术与工程—水产品加工及贮藏工程]