Bismuth Nano-Nest/Ti

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 derivative QDs (Ti3CN QDs) with excellent luminescence performance were prepared as the ECL luminescent. The N doping in Ti3CN QDs can effectively improve the luminescence performance and catalytic activity. Therefore, the luminescence performance of QDs has been effectively improved. Furthermore, the bismuth nano-nest structure with a strong localized surface plasmon resonance effect has been designed as the sensing interface via the electrochemical deposition method. It was worth noticed that the morphology of bismuth nanomaterials can be controlled effectively on the electrode surface by the step potential method. Due to the abundant surface plasmon hot spots generated between the bismuth nano-nests, the isotropic ECL signal of Ti3CN QDs can be not only significantly enhanced by 5.8 times but also converted into polarized emission. Finally, the bismuth nano-nest/Ti3CN QD-based SPC-ECL sensor was used to quantify miRNA-421 in the range of 1 fM to 10 nM. The biosensor has been successfully used for miRNA in ascites samples from gastric cancer patients, which indicated that the SPC-ECL sensor developed in this study has great potential for clinical analysis.