Nitrogen-doped Ti3C2 MXene quantum dots as novel high-efficiency electrochemiluminescent emitters for sensitive mucin 1 detection

Recently, some MXenes quantum dots (QDs) have been demonstrated to exhibit high photoluminescence quantum yield, however, there are relatively few reports on MXenes QDs with high electrochemiluminescence (ECL) quantum efficiency. In this work, we discovered that nitrogen-doped titanium carbide QDs (N-Ti3C2 QDs) which were synthesized via a simple hydrothermal method using Ti3C2 as the precursor and ethylenediamine as the nitrogen source not only exhibited ECL property, but also possessed higher ECL quantum efficiency than Ti3C2 QDs, the relative ECL quantum efficiency of N-Ti3C2 QDs was calculated to be 1.58. Therefore, due to its high ECL efficiency, excellent metal conductivity, chemical stability, and non-toxicity, N-Ti3C2 QDs were utilized as an ideal new luminescent material to construct ECL immunosensor for sensitive determination of mucin 1 (MUC1) in this work, which is closely associated with the development of malignancy. Furthermore, ECL signal of the immunosensor could be further enhanced, which was ascribed to that the prepared N-Ti3C2 QDs can promote the reduction of co-reactant S2O82- to generate abundant sulfate radicals for acceleration the ECL reaction of N-Ti3C2 QDs. Consequently, the ECL immunosensor based on N-Ti3C2 QDs/S2O82- system can achieve sensitive MUC1 detection with a low detection limit of 0.31 fg mL−1. In a word, other MXenes QDs with excellent electrical conductivity, good stability and non-toxicity are also likely to be developed as promising ECL emitter for promoting the ECL development in biological analysis.