MXene-Integrated Composites for Next-Generation Photoelectrochemical Molecular Diagnostics

MXenes, a family of two-dimensional (2D) materials known for their characteristic electrical, optical, and surface properties, have emerged as promising candidates for advancing the performance of photoelectrochemical (PEC) biosensing technologies. When integrated into composites, including carbon-based materials, metal nanoparticles, and conductive polymers, MXenes' intrinsic properties, such as high surface area, high electrical conductivity, and tunable surface chemistry, can contribute to improving the sensitivity, selectivity, and stability of PEC biosensors. These characteristics make MXenes suitable for applications across various sectors, such as healthcare, food safety, and environmental monitoring. This review comprehensively outlines the core principles of PEC sensing, highlighting the role of MXene-based composites and light-driven processes in facilitating the detection of miRNA, protein biomarkers, small biomolecules, drug molecules, pesticides, and organic contaminants. It further explores recent advancements in MXene composites for detecting a broad spectrum of biological targets in complex biological samples. The review also addresses challenges, including the requirements for stability, reproducibility, biocompatibility, and scalability in various practical applications. Finally, it discusses future perspectives on MXene-integrated composites for PEC biosensing and their potential applications in clinical diagnostics, precision medicine, food safety, and environmental monitoring.