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

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 deriv-ative (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.

Automated summary

Finding a pair of electrochemiluminescence emitters that can act as both energy donor and acceptor simultaneously is crucial for the development of ratiometric ECL aptasensors based on ECL resonance energy transfer strategy (ECL-RET). In this study, aggregation-induced emission gold nanoclusters (AuNCs) and amino-terminated perylene derivative (PTC-NH2) with broad absorption range were combined as a novel ECL-RET donor-acceptor pair. By measuring the ratio of AuNCs and PTC-NH2 ECL intensities, a potential-resolved ratiometric ECL aptasensor for detecting lead ions (Pb2+) was successfully developed with low detection limit and excellent selectivity. The proposed aptasensor demonstrated favorable feasibility for Pb2+ assays in soil samples.