Next-Generation MXene-Hydrogel Hybrids: Frontiers in Biosensing and Environmental Surveillance

Hydrogels have emerged as promising soft materials for applications in sensing, energy storage, and wearable electronics due to their tunable physicochemical properties and intrinsic biocompatibility. The integration of two-dimensional transition metal carbides/nitrides (MXenes) into hydrogel matrices has enabled the development of highly conductive, flexible, and electrochemically active composites for advanced sensing platforms. MXene-hydrogel hybrids exhibit enhanced charge transport, mechanical stability, and interfacial functionality, making them particularly attractive for electrochemical sensing applications. This review provides a comprehensive overview of MXene-hydrogel composites, focusing on their design strategies, synthesis approaches, and electrochemical sensing performance. Despite these advantages, critical challenges remain, including susceptibility of MXenes to oxidation, restacking of nanosheets, limited long-term stability, and difficulties in reproducible and scalable synthesis. These limitations significantly impede their translation into practical and commercial devices. Particular emphasis is placed on identifying current bottlenecks and outlining future research directions, including the development of oxidation-resistant MXenes, advanced hybrid architectures, scalable fabrication techniques, and integration into wearable and point-of-care sensing systems. Addressing these challenges is essential for realizing the full potential of MXene-hydrogel systems in next-generation electrochemical sensing technologies.