2D Materials: From Design and Synthesis to Applications in Electrical and Electrochemical Biosensors.

This review critically analyzes various 2D materials-either synthesized or exfoliated from bulk 3D counterparts-for electrochemical and electrical biosensing applications. Each material exhibits unique electrochemical properties and benefits from its inherent 2D features, enabling abundant active sites for biomolecule interaction. Key challenges include synthesizing or exfoliating these materials and processing them for the cost-effective and scalable production of biosensors. Additionally, the functionalization of 2D materials is crucial for effective bioreceptor immobilization, which directly affects selectivity, sensitivity, and overall performance. Certain 2D materials are better suited for specific sensing applications. For instance, 2D metal-organic frameworks or covalent organic frameworks show potential in electrochemical sensing due to their porous structures and high density of active sites. Transition metal dichalcogenides, such as MoS and WS, show promise for field-effect transistor-based biosensors. Reduced graphene oxide and MXenes, with tunable surface functionalities, show promise for both electrical and electrochemical sensing platforms. Monoelemental 2D materials (Xenes) hold dual-sensing potential, though synthesis and stability remain challenges for some. Hydrogenated Xenes offer improved stability, semiconducting behavior, and functionalization potential, making them strong candidates for biosensing. This review highlights these challenges and advantages while providing perspectives and future directions for optimizing 2D materials in biosensor development.