At the end of 2019, the novel coronavirus disease 2019 (COVID-19), a cluster of atypical pneumonia caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has been known as a highly contagious disease. Herein, we report the MXene/P–BiOCl/Ru(bpy)₃²⁺ heterojunction composite to construct an electrochemiluminescence (ECL) immunosensor for SARS-CoV-2 nucleocapsid protein (CoVNP) determination. Two-dimensional (2D) material ultrathin phosphorus-doped bismuth oxychloride (P–BiOCl) is exploited and first applied in ECL. 2D architectures MXene not only act as “soft substrate” to improve the properties of P–BiOCl, but also synergistically work with P–BiOCl. Owing to the inimitable set of bulk and interfacial properties, intrinsic high electrochemical conductivity, hydrophilicity and good biocompatible of 2D/2D MXene/P–BiOCl/Ru(bpy)₃²⁺, this as-exploited heterojunction composite is an efficient signal amplifier and co-reaction accelerator in the presence of tri-n-propylamine (TPA) as a coreactant. The proposed MXene/P–BiOCl/Ru(bpy)₃²⁺-TPA system exhibits a high and stable ECL signal and achieves ECL emission quenching for “signal on-off” recognition of CoVNP. Fascinatingly, the constructed ECL biosensor towards CoVNP allows a wide linear concentration range from 1 fg/mL to 10 ng/mL and a low limit of detection (LOD) of 0.49 fg/mL (S/N = 3). Furthermore, this presented strategy sheds light on designing a highly efficient ECL nanostructure through the combination of 2D MXene architectures with 2D semiconductor materials in the field of nanomedicine. This ECL biosensor can successfully detect CoVNP in human serum, which can promote the prosperity and development of diagnostic methods of SARS-CoV-2.

2019年底，由严重急性呼吸系统综合症冠状病毒2（SARS-CoV-2）引起的一组非典型肺炎2019新型冠状病毒病（COVID-19）被称为高度传染性疾病。在此，我们报告了 MXene/P–BiOCl/Ru(bpy) ₃ ²⁺异质结复合材料构建电化学发光 (ECL) 免疫传感器用于 SARS-CoV-2 核衣壳蛋白 (CoVNP) 测定。二维（2D）材料超薄磷掺杂氯氧化铋（P-BiOCl）被开发并首次应用于ECL。2D 架构 MXene 不仅可以作为“软基板”来改善 P-BiOCl 的性能，而且还可以与 P-BiOCl 协同工作。由于 2D/2D MXene/P-BiOCl/Ru(bpy) ₃ ²⁺具有无与伦比的体积和界面特性、固有的高电化学电导率、亲水性和良好的生物相容性，这种所开发的异质结复合材料是一种高效的信号放大器和在三正丙胺 (TPA) 作为共反应剂存在下的共反应促进剂。提出的 MXene/P–BiOCl/Ru(bpy) ₃²⁺ -TPA 系统表现出高且稳定的 ECL 信号，并实现 ECL 发射猝灭，用于 CoVNP 的“信号开关”识别。令人着迷的是，针对 CoVNP 构建的 ECL 生物传感器允许从 1 fg/mL 到 10 ng/mL 的宽线性浓度范围和 0.49 fg/mL ( S /N = 3) 的低检测限 (LOD)。此外，该策略揭示了通过将二维 MXene 架构与纳米医学领域的二维半导体材料相结合来设计高效的 ECL 纳米结构。这种ECL生物传感器可以成功检测人血清中的CoVNP，可以促进SARS-CoV-2诊断方法的繁荣和发展。