Bismuth Nano-Nest/Ti3CN Quantum Dot-Based Surface Plasmon Coupling Electrochemiluminescence Sensor for Ascites miRNA-421 Detection

In this study, a novel surface plasmon-coupled electrochemiluminescence(SPC-ECL) biosensor was developed based on bismuth nano-nest and Ti3CN quantum dots (Ti3CN QDs). First, MXene derivativeQDs (Ti3CN QDs) with excellent luminescence performancewere prepared as the ECL luminescent. The N doping in Ti3CN QDs can effectively improve the luminescence performance and catalyticactivity. Therefore, the luminescence performance of QDs has beeneffectively improved. Furthermore, the bismuth nano-nest structurewith a strong localized surface plasmon resonance effect has beendesigned as the sensing interface via the electrochemical depositionmethod. It was worth noticed that the morphology of bismuth nanomaterialscan be controlled effectively on the electrode surface by the steppotential method. Due to the abundant surface plasmon hot spots generatedbetween the bismuth nano-nests, the isotropic ECL signal of Ti3CN QDs can be not only significantly enhanced by 5.8 timesbut also converted into polarized emission. Finally, the bismuth nano-nest/Ti3CN QD-based SPC-ECL sensor was used to quantify miRNA-421in the range of 1 fM to 10 nM. The biosensor has been successfullyused for miRNA in ascites samples from gastric cancer patients, whichindicated that the SPC-ECL sensor developed in this study has greatpotential for clinical analysis.