Multifunctional AuAgPt Nanoframes for a Stimuli-Responsive Electrochemiluminescence Aptasensor
Changxiao Song, Jingxian Li, Futing Wang, Ziyang Peng, Yan Shen, Chongyang Huang, Su-Ping Deng, Hongfen Yang, Dan Yang, Ren Cai, Weihong Tan
Abstract
A multifunctional electrochemiluminescence (ECL) coreaction accelerator, AuAgPt nanoframes (NFs), is described for use in an ECL aptasensor for highly sensitive aflatoxin B1 (AFB1) detection. As a signal quencher, the broad UV–vis absorption spectrum of AuAgPt nanosheets (NSs) overlaps the ECL emission spectrum of g-C 3 N 4 @Au, triggering an ECL resonance energy transfer (ECL-RET). By the adjustment of the dosage of hydrogen peroxide (H 2 O 2 ), the AuAgPt NSs are transformed into AuAgPt NFs because H 2 O 2 etches Ag in AuAgPt NSs into Ag +, which disrupts the RET process. The as-formed AuAgPt NFs act as a coreaction accelerator to enhance the ECL response of the g-C 3 N 4 @Au/K 2 S 2 O 8 system. Without AFB1, the Ag-dependent DNAzyme is inactive, and a strong ECL signal is observed. After AFB1 is added, the AFB1 aptamer targets AFB1 and the DNAzyme active site is exposed. As-generated Ag + further activates DNAzyme to cut the substrate strand (S-DNA), which causes AuAgPt NFs to detach from the electrode surface and the ECL signal to significantly decrease. Under optimal conditions, the proposed ECL aptasensor exhibits high sensitivity with a limit of detection (LOD) of 0.11 fg/mL in the range of 1 fg/mL to 1 μg/mL for AFB1 detection.