表面老化によるTi系MXeneの細胞取り込みおよび反応性の抑制を介したミトコンドリア毒性の減弱

Two-dimensional MXenes, particularly titanium carbide (Ti₃C₂) and titanium carbonitride (Ti₃CN), have garnered increasing interest for applications spanning from green energy storage to biomedicine. However, their inevitable exposure to aqueous or physiological environments during use and disposal induces oxidative aging, potentially altering their physicochemical properties and biological effects. Here, we systematically compared the cytotoxicity and mechanistic pathways of pristine and aged Ti₃C₂ and Ti₃CN MXenes in human colonic epithelial cells. Material characterization revealed that aging promoted surface oxidation, partial TiO₂ formation, and aggregation, with more pronounced changes in Ti₃C₂. Cellular assays demonstrated that pristine MXenes, particularly Ti3CN, induced significant mitochondrial swelling, disruption of cristae, lysosomal perturbation, overproduction of reactive oxygen species, and apoptosis. In contrast, aged MXenes exhibited attenuated cellular uptake, reduced oxidative stress, and diminished mitochondrial damage, correlating with lower apoptosis rates. These findings suggest that oxidative aging serves as an intrinsic detoxification process by modulating the surface reactivity of MXene and its subcellular interactions. This work highlights the necessity of incorporating environmental transformation into MXene safety assessments and provides mechanistic insights for designing safer, application-relevant 2D nanomaterials.