A novel work function tuning strategy-based ECL sensor with sulfur dots and Au NP@MoS2 nanosheet heterostructure for triple-negative breast cancer diagnosis

In this work, a novel biosensor has been developed based on the sulfur dots and Au NP@MoS2 nanosheet heterostructure. On the one hand, highly luminescent sulfur dots were prepared by the microwave-assisted synthesis method as electrochemiluminescence (ECL) emitter. On the other hand, in order to regulate the ECL signal, Au NP@MoS2 nanosheet heterostructure has been constructed. In the heterostructure, the work function of 2-D MoS2 nanosheet with excellent electronic properties was relatively low than that of Au NPs. Due to the work function tuning strategy, there were local electrophilic or nucleophilic regions in the heterostructure. The resulted self-driven charge transfer at the interface further increased the local electron density of Au NPs. Therefore, the ECL quenching effect caused by the close-range electron transfer between the sulfur dots and the Au NPs has been effectively suppressed. And the localized surface plasmon resonance (LSPR) effect of Au NPs played a primary role to amplify the ECL signal of sulfur dots. Finally, the sensing system was designed for the detection of miRNA-210 from 0.1 pM to 10 nM. The ECL sensor showed good analytical performance in the detection of triple-negative breast cancer tumor and paracancerous tissues with the recoveries ranging from 91.7% to 102.4%. The satisfactory results indicated the work function tuning strategy-based sensor with sulfur dots and Au NP@MoS2 nanosheet heterostructure possessed great potential in the ECL research and clinical analysis.