Electrostatic Interaction-Induced Aggregation-Induced Emission-Type AgAu Bimetallic Nanoclusters as a Highly Efficient Electrochemiluminescence Emitter for Ultrasensitive Detection of Glial Fibrillary Acidic Protein

Herein, the aggregation-induced emission (AIE)-type carbox-ymethyl chitosan (CMCS)@6-aza-2-thiothymine (ATT) templated AgAu bimetallic nanoclusters (CMCS@ATT-AgAu BMNCs) with superior electro-chemiluminescence (ECL) emission were first synthesized to construct a biosensor for the ultrasensitive detection of glial fibrillary acidic protein (GFAP). Impressively, unlike the traditional AIE-type bimetallic nanoclusters (BMNCs) obtained by complicated multi-step synthesis, the AIE-type CMCS@ATT-AgAu BMNCs were prepared by the electrostatic interaction between the negatively charged ATT and positively charged CMCS, in which the molecule ATT was served as a capping and reducing agent of bimetal ions. In addition, a rapidly moving cholesterol labeled DNA walker was constructed to move freely on the lipid bilayer to increase its moving efficiency, and the well-regulated DNA was intelligently designed to further improve its walking efficiency for rapid and ultrasensitive detection of GFAP with a limit of detection (LOD) as low as 73 ag/mL. This strategy proposed an avenue to synthesize highly efficient BMNCs-based ECL emitters, which have great potential in ultrasensitive biosensing for early diagnosis of diseases.

Automated summary

In this study, AIE-type carboxymethyl chitosan (CMCS)@6-aza-2-thiothymine (ATT) templated AgAu bimetallic nanoclusters (CMCS@ATT-AgAu BMNCs) with strong electro-chemiluminescence (ECL) emission were synthesized for ultrasensitive detection of glial fibrillary acidic protein (GFAP). Unlike traditional AIE-type BMNCs synthesized through complicated multi-step methods, the AIE-type CMCS@ATT-AgAu BMNCs were prepared through electrostatic interaction between ATT and CMCS, in which ATT acted as both a capping and reducing agent of bimetal ions. Moreover, a cholesterol-labeled DNA walker was constructed to freely move on a lipid bilayer and improve its walking efficiency for the rapid and ultrasensitive detection of GFAP with a low limit of detection (LOD) of 73 ag/mL. This strategy offers a new approach to synthesize highly efficient BMNCs-based ECL emitters for early disease diagnosis.