在这项工作中，基于双金属 MXene 衍生物 QDs（Mo2TiC2 QDs）和 SnS2 纳米片/磷脂双层膜开发了一种新型 ECL 生物传感器，用于检测胃癌标记 miRNA-27a-3p。一方面，Mo2TiC2 QDs 的带间激发可以注入额外的载流子，这些载流子受边界效应的抑制较小，并对发光过程做出了重要贡献。半导体 Mo2TiC2 进一步抑制了内部电场和氧化电位的形成。因此，Mo2TiC2 QDs 具有优异的光强和更好的稳定性。另一方面，涂有磷脂双层膜的 SnS2 纳米片被设计为传感界面。SnS2 纳米片不仅由于其巨大的表面积和低介电常数而增强了 Mo2TiC2 QDs 的光强度，还提高了磷脂双层膜的稳定性。由于 Mo2TiC2 QDs 和磷脂双层膜修饰的 SnS2 纳米片的优异性能和协同作用，传感系统在分析应用中显示出高灵敏度和良好的重复性。因此，生物传感器在广泛的浓度范围内显示出 ECL 强度和 miRNA-27a-3p 浓度之间良好的线性相关性，检测限低至 1 fM。包括 Mo2TiC2 QDs、SnS2 纳米片和磷脂双层膜的联合贡献，传感系统在临床应用方面具有巨大的潜力。版权所有 © 2023 Elsevier B.V.

In this work, a novel ECL biosensor has been developed based on bimetallic MXene derivative QDs (Mo2TiC2 QDs) and SnS2 nanosheets/lipid bilayer to detect the gastric cancer marker miRNA-27a-3p. On the one hand, the inter-band excitation of Mo2TiC2 QDs can inject the additional carriers, which were less suppressed by boundary effects and made a significant contribution to the luminescence process. Semiconductor Mo2TiC2 further inhibited the formation of internal electric field and potential oxidation. Therefore, Mo2TiC2 QDs processed superior luminous intensity and better stability. On the other hand, SnS2 nanosheets coated with phospholipid bilayer were designed as sensing interface. SnS2 nanosheets not only enhanced the luminous intensity of Mo2TiC2 QDs by virtue of their large surface area and low dielectric constant, but also improved the stability of lipid bilayer. Due to the excellent properties and synergy work of Mo2TiC2 QDs and the lipid bilayer-modified SnS2 nanosheets, the sensing system displayed high sensitivity and good reproducibility in the analysis application. As a result, the biosensor displayed good linear correlation between the ECL intensity and the concentration of miRNA-27a-3p over a wide range from 1 fM to 10 nM with the detection limit as low as 1 fM. The sensing system including the joint contribution of Mo2TiC2 QDs, SnS2 nanosheets and lipid bilayers had great potential for clinical applications.Copyright © 2023 Elsevier B.V. All rights reserved.