Highly sensitive electrochemiluminescence sensing platform based on copper nanoclusters synthesized via a DNA nanoribbon template for the detection of cancer cells

Abstract

Herein, we presented a simple ultra-sensitive "on-off-on" electrochemiluminescence (ECL) biosensor that uses copper nanoclusters (CuNCs) synthesized via a DNA nanoribbon (DNR) template (DNR-CuNCs) as a sensing platform coupled with target-cycle amplification for the sensitive and rapid detection of cancer cells that overexpress proteins. DNR templated DNR-CuNCs, a well-ordered ECL emitter, was integrated into the nucleic acid framework structure to self-assembly, which enhanced the ECL intensity benefit from reduced band gap and accelerated electron transfer reaction of CuNCs. Additionally, an optimized exonuclease III (Exo III)-assisted cycle amplification method was introduced to efficiently convert trace target biomarkers into a substantial output of DNA, significantly improving target conversion efficiency and boosting the ECL signal. Consequently, MUC1 proteins were sensitively detected by the ECL biosensor throughout a broad concentration range, from 1 fg·mL−1 to 1 ng·mL−1, with a low limit of detection (LOD) of 0.061 fg·mL−1, and successfully detected MUC1-overexpressing cancer cells (using MCF-7 cancer cells as a model), accurately identifying MCF-7 cells in the concentration range of 10–100,000 cells·mL−1 with a LOD of 5 cells·mL−1. This research, for the first time, introduced a DNR-CuNCs ECL biosensor for the highly sensitive detection of living cells and their associated surface proteins. The detection of biomarker proteins and specific cells is greatly promising by applying this simple, sensitive, and specific strategy.