Juggling Surface Charges of 2D Niobium Carbide MXenes for a Reactive Oxygen Species Scavenging and Effective Targeting of the Malignant Melanoma Cell Cycle into Programmed Cell Death

There are several problems that need to be overcome to enable smooth and sustainable clinical translation of the MXene materials, including hard controllable surface chemistry. In this study, we show for the first time that, by using surface modification with poly-l-lysine (PLL), it is possible to completely invert the highly negative surface charge of the 2D niobium carbide MXenes (viz., Nb₂C and Nb₄C₃) toward a highly positive value. Switching the surface charge of MXenes results in obtaining important biological effects in vitro such as targeting of malignant cells and inducing cell cycle arrest at the G₀/G₁ phase and triggering apoptosis, i.e., programmed cell death—the most desirable effect for designing anticancer nanodrugs, which should directly target the cells’ physiology instead of generating direct toxicity. In addition, both 2D Nb₂C/PLL and Nb₄C₃/PLL MXenes showed significant adjustment of their biocompatibilities in relation to normal skin cells. The obtained results suggest that Nb-MXenes can be used as scavengers for the reactive oxygen species (ROS). This study formulates an important step toward further development of MXene-based nanotherapies and strategies for cancer cell elimination in relation to standard therapeutic procedures currently being developed for these materials.