Ultrasensitive electrochemical aptasensor based on CoSe2/AuNRs and 3D structured DNA-PtNi@Co-MOF networks for the detection of zearalenone

Abstract

In this work, an electrochemical aptasensor including CoSe2/AuNRs, 3D structured (3 ds) DNA-PtNi@Co-MOF networks and nicking enzyme was employed to detect zearalenone (ZEN). Herein, CoSe2/AuNRs with large surface area and high conductivity was synthesized to provide a favorable platform for the construction of aptasensor. 3 ds DNA-PtNi@Co-MOF networks with intrinsic catalysis towards thionine (Thi) could largely increase the amount of signal tags Thi and signal amplifiers PtNi@Co-MOF to amplify the current response. When ZEN existed, the aptamer (Apt) was opened to obtain the target complex (ZEN-Apt), thereby further opening hairpin H1 through DNA hybridization. With the aid of nicking enzyme, the ZEN-Apt was released to initiate the next hybridization process, resulting in the production of amounts of residual DNA H1. Thi labeled DNA H2-PtNi@Co-MOF can be introduced by hybridization of residual DNA H1 and hairpin base sequence of DNA H2 to obtain a significantly amplified current. Eventually, higher current was obtained through the further adding of Thi labeled 3 ds DNA-PtNi@Co-MOF networks. As a result, the aptasensor exhibited a low detection limit of 1.37 fg/mL (S/N = 3). Furthermore, the resultant aptasensor exhibited satisfactory stability and specificity, and was applied to detect ZEN in maize samples.