MXenes-based nanomaterials for biosensing and biomedicine

As recently developed two-dimensional (2D) materials, MXenes have attracted great attention in the fields of sensing, catalysis, energy, and electromagnetism due to their good electrical, mechanical, and optical properties and their biocompatibility. Their rich elemental composition, diverse surface functional groups and flexible bandgaps enable them to exhibit ideal physicochemical properties that are superior to those of traditional 2D materials. Therefore, MXenes not only serve as ideal biosensing materials but also show great potential in biomedical-related applications. In this review, we summarize the latest research on MXenes in the fields of biosensing and biomedicine. First, we introduce the different synthesis strategies and unique properties of MXenes. Then, according to the sensing mechanism, we divide the biosensing applications of MXenes into three subcategories: electrochemical, photochemical, and optoelectrochemical biosensors. Moreover, we systematically evaluate the biomedical applications of MXenes from four aspects: antibacterial activity, bioimaging, therapeutics and theranostics. How the specific chemical and physical properties of MXenes that can influence the efficiency of biosensing and biomedicine are highlighted, as well as the structure-performance relationships determining detection sensitivity and the toxicity of materials. Finally, we discuss the recent challenges and future prospects and opportunities for MXenes. It is expected that the review could promote the development of related fields.