作者列表：Chen Xiaoye, Liu Yun, Lu Yichen, Xiong Xiong, Li Yi, Liu Yuanjian, Xiong Xiaohui

期刊：MICROCHIMICA ACTA

影响因子：5.479

发表时间：2019-1-14

DOI:10.1007/s00604-019-3236-9

Abstract

A rapid ａnd ultrasensitive method is described for the detection of staphylococcal enterotoxin B （SEB）. It is based on the formation of a dendritic DNA superstructure by integrating （a） target-induced triggering of DNA release with （b） signal amplification by a hybridization chain reaction. Partially complementary pairing of aptamer ａnd trigger DNA forms a duplex structure. The capture DNA is then placed on the surface of a gold electrode through gold-thiol chemistry. In the presence of SEB, the aptamer-target conjugate is compelled to form. This causes the release of trigger DNA owing to a strong competition with SEB. The trigger DNA is subsequently hybridized with the partial complementary sequences of the capture DNA to trigger HCR with three auxiliary DNA sequances （referred to as H1, H2, H3）. Finally, the dendritic DNA superstructure is bound to hexaammineruthenium（III） cation by electrostatic adsorption ａnd assembled onto the modified gold electrode. This produces an amplified electrochemical signal that is measured by chronocoulometry. Under optimal conditions, the charge difference increases linearly with the logarithm of the SEB concentrations in the range from 5 pg·mL−1 to 100 ng·mL−1 with a detection limit as low as 3 pg·mL−1 （at S/N = 3）.