A potential-resolved ratiometric electrochemiluminescence aptasensor for Pb2+: Gold nanoclusters and amino-terminated perylene derivative as both emitters and resonance energy transfer donor-acceptor pair

Abstract

Searching for a pair of electrochemiluminescence (ECL) emitters that can be simultaneously applied as energy donor-acceptor pair is very vital for ECL resonance energy transfer strategy (ECL-RET)-based ratiometric ECL aptasensors, as it can avoid the complex design caused by the addition of exogenous donor or acceptor. Herein, gold nanoclusters (AuNCs) with aggregation-induced emission property and amino-terminated perylene derivative (PTC-NH2) with a broad absorption range were firstly combined to generate the anodic and cathodic ECL signals, respectively. Importantly, they were also operated as a novel ECL-RET donor-acceptor pair due to their favorable spectral overlap. On this basis, a potential-resolved ratiometric ECL aptasensor was established to detect lead ions (Pb2+). Specifically, the energy of AuNCs was absorbed by PTC-NH2 in the absence of Pb2+, leading to a decrease of the anodic ECL signal and the appearance of the cathodic ECL signal. Upon the addition of Pb2+, the ECL-RET process was impeded, and the ECL signals were reversed. By measuring the ratio of AuNCs and PTC-NH2 ECL intensities, the developed ratiometric ECL aptasensor displayed a low detection limit of 0.05 pM with excellent selectivity and satisfactory stability. Finally, the proposed aptasensor presented favorable feasibility for Pb2+ assays in soil samples.