Since the isolation of graphene in 2004, two-dimensional (2D) materials such as transition metal dichalcogenide (TMD) have attracted numerous interests due to their unique van der Waals structure, atomically thin body, and thickness-dependent properties. In recent years, the applications of TMD in public health have emerged due to their large surface area and high surface sensitivities, as well as their unique electrical, optical, and electrochemical properties. In this review, we focus on state-of-the-art methods to modulate the properties of 2D TMD and their applications in biosensing. Particularly, this review provides methods for designing and modulating 2D TMD via defect engineering and morphology control to achieve multi-functional surfaces for molecule capturing and sensing. Furthermore, we compare the 2D TMD-based biosensors with the traditional sensing systems, deepening our understanding of their action mechanism. Finally, we point out the challenges and opportunities of 2D TMD in this emerging area.

Two-dimensional (2D) materials are promising candidates in wide applications including energy storage and conversion, sensors, flexible devices, etc. The low-cost production of 2D materials with large quantities and demanded quality is the precondition for their commercial uses. For graphene and its derivatives, relatively mature techniques have been established for their scalable preparation and industrial applications. Whereas the mass production of 2D materials beyond graphene is still in its early age and it lacks a summary on this topic. This review systematically describes the state-of-the-art approaches for high-yield preparation of 2D materials beyond graphene, including "top-down" exfoliation and "bottom-up" synthetic approaches. In particular, each method is discussed from the perspectives of its principle, optimization attempts, characteristics of the obtained 2D materials, and its scalability potential. The applications that require massively-produced 2D materials are highlighted, including electrocatalysis, batteries, supercapacitors, mechanical and chemical sensors, as well as electromagnetic interference shielding and microwave absorption devices. Finally, we propose the challenges and opportunities for scalable preparation and commercial applications of 2D materials.