Biocompatible and Oxidation‐Resistant Ti3C2Tx MXene with Halogen‐Free Surface Terminations

Abstract

AbstractSurface chemistry influences not only physicochemical properties but also safety and applications of MXene nanomaterials. Fluorinated Ti3C2Tx MXene, synthesized using conventional HF‐based etchants, raises concerns regarding harmful effects on electronics and toxicity to living organisms. In this study, well‐delaminated halogen‐free Ti3C2Tx flakes are synthesized using NaOH‐based etching solution. The transversal surface plasmon mode of halogen‐free Ti3C2Tx MXene (833 nm) confirmed red‐shift compared to conventional Ti3C2Tx (752 nm), and the halogen‐free Ti3C2Tx MXene has a different density of state by the high proportion of –O and –OH terminations. The synthesized halogen‐free Ti3C2Tx exhibits a lower water contact angle (34.5°) and work function (3.6 eV) than those of fluorinated Ti3C2Tx (49.8° and 4.14 eV, respectively). The synthesized halogen‐free Ti3C2Tx exhibits high biocompatibility with the living cells, as evidenced by no noticeable cytotoxicity, even at very high concentrations (2000 µg mL⁻1), at which fluorinated Ti3C2Tx caused ≈50% reduction in cell viability upon its oxidation. Additionally, the oxidation stability of halogen‐free Ti3C2Tx is enhanced unexpectedly, which cumulatively provides a good rationale for pursuing the halogen‐free routes for synthesizing MXene materials for their uses in biomedical and therapeutic applications.