High-efficiency interparticle DNA walker amplifier combined with N-Ti3C2 quantum dots as electrochemiluminescence emitters for sensitive protein assay

Abstract

In this work, an electrochemiluminescence (ECL) biosensor based on interparticle DNA walker as effective signal amplification strategy and N-Ti3C2 QDs as high-efficiency emitters was designed for sensitive assay of mucin 1 (MUC1), which is closely related to the occurrence and development of tumors. First, an interparticle DNA walker which contains walking particles (WPs) and orbit particles (OPs) was fabricated. In the presence of target MUC1 and DNAzyme, the WPs can walk along the surface of OPs, and they can continue to walk along next OPs after completing previous walk. As the moving freedom and area improved, the interparticle DNA walker could effectively improve the conversion efficiency of target. Furthermore, N-Ti3C2 QDs with high ECL luminous efficiency were synthesized by using polyethyleneimine (PEI) as nitrogen source. Due to the nitrogen-rich of PEI, the relative ECL quantum efficiency of the proposed N-Ti3C2 QDs was calculated to be 1.5 times higher than our previous reported N-Ti3C2 QDs that utilizing ethylenediamine as nitrogen source. Therefore, taking the advantage of the improved moving freedom and area of the interparticle DNA walker and high ECL efficiency of the proposed N-Ti3C2 QDs, the fabricated ECL biosensor for MUC1 determination displayed a low detection limit with a wide linear range, which provides a potential feasible method for other protein sensitive assay.