Silver Nanocluster-Tagged Electrochemiluminescence Immunoassay with a Sole and Narrow Triggering Potential Window

Abstract

The commercialized electrochemiluminescence (ECL) immunoassay is carried out by holding luminophore Ru­(bpy)3 2+ at a given potential. Designing an electrochemiluminophore with a narrow triggering potential window is strongly anticipated to decrease the electrochemical cross-talk and improve the flux of the commercialized ECL immunoassay in a potential-resolved way. Herein, L-penicillamine-capped silver nanoclusters (LPA-AgNCs) are facilely synthesized and utilized as tags to perform the ECL immunoassay with a sole and narrow triggering potential window of 0.24 V by employing hydrazine (N2H4) as a coreactant. The maximum ECL emission of the LPA-AgNCs/N2H4 system is located ca. +1.27 V. Upon immobilizing LPA-AgNCs onto the electrode surface via forming a sandwich immunocomplex, the ECL of LPA-AgNCs/N2H4 can be utilized to sensitively and selectively determine human carcinoembryonic antigen from 0.5 to 1000 pg/mL with a low limit of detection of 0.1 pg/mL (S/N = 3). This work might open a way to screen electrochemiluminophores for the multiple ECL immunoassay in a potential-resolved way.

Programmable DNA Templates for Silver Nanoclusters Synthesis To Develop On-Demand FRET Aptasensor

“…Conventionally, monolayers of organic ligands have been employed for passivating silver atoms to produce AgNCs. Moreover, recent advances have made it possible to synthesize hydrosoluble AgNCs with adjustable fluorescence emission in various templates, such as polymers, short molecule ligands, , polyoxochromate, and DNA strands. − Among different templates, DNA is an ideal template for AgNCs synthesis because cytosine bases on single-stranded DNA (ssDNA) possess high affinity to silver ions . DNA-templated AgNCs (AgNCs-DNA) can be conveniently synthesized via a straightforward one-pot method, thereby bypassing the tedious procedures of biomolecular labeling. , The programmability of DNA oligonucleotides endows them with the triple functions of serving as a synthetic template and playing a pivotal role in fluorescence regulation as well as targeted recognition.…”