Ratiometric electrochemiluminescence lab-on-paper device for DNA methylation determination based on highly conductive copper paper electrode

Herein, a ratiometric electrochemiluminescence (ECL) lab-on-paper platform, based on enhancing effect of the N-(4-aminobutyl)-N-ethylisoluminol-functionalized glutathione-coated cobalt/gold bimetallic nanoclusters (GCAL) and quenching effect of carbon quantum dots (CQDs), as well as benefiting from high conductivity copper paper electrode, was developed to achieve accurate and sensitive analysis of DNA methylation. Concretely, due to one-to-multiple amplification effect, one target DNA could initiate the formation of supersandwich structure with multiple signal probes labeled with GCAL. Thus, the GCAL signal enhancement effect was realized. Simultaneously, multiple signal probes are connected to hinder the electron conduction rate on the electrode surface, which results in the quenching of CQDs signal. With the method proposed here, wide linear relationship in the range of 1 fM to 10 pM with a low detection limit of 0.27 fM for sensitive detecting methylated DNA was achieved. It is believed that this work provided a rapid, low-cost and stabilized method for specific determination of methylated DNA, and the immediate detection of cancer in the clinic will become possible in the future.