124 Two-dimensional MXenes are increasingly incorporated into biomedical, sensing, and environmental technologies, raising important questions regarding their safety

Abstract Two-dimensional MXenes are increasingly incorporated into biomedical, sensing, and environmental technologies, raising important questions regarding their safety, behaviour, and interactions within biological and occupational settings. Titanium carbide MXene (Ti₃C₂Tx) is of particular interest due to its high conductivity, hydrophilicity, and large reactive surface area. Despite their technological potential, Ti₃C₂Tx materials remain insufficiently characterised from a toxicology and exposure perspective, particularly in relation to their stability, dispersion behaviour, and interactions with biological systems. This study evaluates the biocompatibility and physicochemical behaviour of Ti₃C₂Tx for applications in electrochemical biosensing platforms for Cryptosporidium detection. Using a tiered biocompatibility screening approach in A549, Caco2 and THP-1 cell models, we assessed cytotoxicity, cell–material interactions, and mechanistic responses following MXene exposure. We further investigated MXene-induced inflammatory signalling and oxidative stress, providing insight into early cellular events and hazard-relevant pathways associated with Ti₃C₂Tx MXenes. Complementary light and electron microscopy were employed to examine flake morphology and layer structure, with emphasis on physicochemical features relevant to biological reactivity and potential hazard. These toxicological findings were integrated with preliminary biosensor evaluations to explore how material properties influencing device performance may also shape biological responses. Across all assays, Ti₃C₂Tx MXenes demonstrated generally favourable biocompatibility, eliciting limited adverse effects and maintaining cellular integrity under the tested conditions. Overall, this work contributes to the broader assessment of MXenes as emerging nanomaterials, supporting their responsible development through improved understanding of their biocompatibility, associated hazards, and physicochemical behaviour relevant to exposure and human health risk assessment