The controllable assembly of Cu nanocluster-based aggregation induced ECL strategy for miRNA detection

Copper nanoclusters (Cu NCs) were a new class of non-toxic and economical nanoprobe. However, the low luminescence performance and instability of Cu NCs limited the actual application. Herein, this work developed the novel controllable assembly of Cu NCs aggregation as the electrochemiluminescence (ECL) emitter. Firstly, the hydrophilic Cu NCs was located into the micelles in the reverse microemulsion system. Due to the uniform size of micelles, the number of Cu NCs in each micelle can be controlled exactly. Cerium ions were added to induce Cu NCs to accumulate in micelles. The strong aggregation induced ECL (AIECL) signal can be observed in the controllable assembly of Cu NCs aggregation. The nano-sized Cu NCs assembly not only possessed more strong luminescence and better stability than original Cu NCs, but also kept the good dispersibility over the aggregated bulk. Furthermore, SnS₂ nanosheets increased the specific surface area of the electrode and the number of reactive sites, which further modulated electron transfer to amplify the ECL signal. The ECL sensing system was used to detect miRNA-455-3p in the triple-negative breast cancer tumor tissues. The work provided the new pathway to prepare Cu NCs assembly and expanded AIECL-based sensing application.