Surface functionalized MXene as emerging 2D optical sensors for the monitoring of chemical and biological contaminants

Surface-functionalized MXenes have emerged as highly promising 2D materials for smart optical sensors due to their unique physicochemical properties, including high surface area, tunable surface chemistry, and excellent optical response. These features are enhanced by functionalization of ligands on the surface of MXenes to improve the selectivity, sensitivity, and stability, enabling precise detection of various environmental contaminants such as heavy metals, pesticides, pharmaceuticals, dyes, and biological pathogens. Recent advances have driven the development of fluorescence, surface plasmon resonance (SPR), and surface-enhanced Raman spectroscopy (SERS) based MXene optical sensors, for onsite and real-time monitoring of pollutants. This review highlights the latest progress in synthesis, characterization, and surface modification of MXenes, for the detection of chemical and biological contaminants. Key performance indicators such as limit of detection, reproducibility, response time, and reusability are discussed to evaluate sensing effectiveness. Finally, current challenges and future prospects for MXene-based sensors in sustainable environmental monitoring and regulatory compliance are outlined, offering an in-depth discussion of every aspect of surface functionalized MXene based sensors. This comprehensive discussion paves the way for researchers working in the field of MXene based sensing technology.