Effect of tandem-type stabilization of Nb2CTx MXene on their colloidal and cytotoxic properties

Abstract

Two-dimensional (2D) Nb₂CT_x MXene hold great promise for biomedical applications due to their tunable surface chemistry and biocompatibility. However, their practical use requires long-term colloidal and oxidative stability. Here, we propose a tandem-type stabilization strategy combining antioxidant protection and macromolecular surface functionalization. Nb₂CT_x was first treated with L-ascorbic acid (LA) to suppress oxidation by binding to reactive edges, followed by modification with polyethylene glycol (PEG), poly-L-lysine (PLL), or polydopamine (PDA). This dual approach enhanced stability in biological media — phosphate-buffered saline (PBS) and Dulbecco’s Modified Eagle’s Medium (DMEM) — while preserving non-cytotoxicity toward A375 and HaCaT skin cell lines across 0–100 mg·L⁻¹. Among the tested systems, LA/PEG and LA/PDA-modified MXenes maintained stable zeta potentials (−15 to −12 mV) and particle sizes for 72 h, whereas LA/PLL samples showed aggregation and charge loss. This tandem stabilization effectively prevents oxidation and aggregation without compromising biocompatibility, offering a versatile route for developing oxidation-resistant MXenes for biomedical and nanomedicine applications.