Designable synthesis of a novel layered MXene loaded gold nanocluster composite for efficient electrochemical sensing of homocysteine in biological samples

The increased level of homocysteine (Hcy) becomes an independent risk factor for various diseases. Quantification of Hcy is helpful to the early diagnosis and treatment of related diseases. For this purpose, it is very necessary to explore innovative materials to construct sensitive electrochemical sensors. Herein, we designed and synthesized a novel composite (BSA-AuCNs/MXene) by using two-dimensional (2D) layered MXene as the matrix and supported with gold nanoclusters (BSA-AuCNs). Combining the properties of the above two materials, the composite was endowed with the ideal characteristics of electrochemical sensing materials such as high electrical conductivity, outstanding catalytic activity, large specific surface area, and good thermal stability. The constructed sensor exhibited excellent analytical behavior for Hcy with a super low detection limit (1.76 nM, S/N = 3). It also displayed satisfactory selectivity, reproducibility, and stability. In addition to detect Hcy in human serum, we also realized the electrochemical detection of Hcy in cell lysate for the first time. This work not only opens up a new way to broaden the application of MXene and gold nanoclusters in the sensing field, but also provides a possibility for their future application in the early diagnosis of Hcy-related diseases.