BackgroundThe biological activity of MXenes has been studied for several years because of their potential biomedical applications; however, investigations have so far been limited to 2D titanium carbides. Although monolayered Ti2NTx MXene has been expected to have biological activity, experimental studies revealed significant difficulties due to obstacles to its synthesis, its low stability and its susceptibility to oxidation and decomposition.ResultsIn this paper, we report our theoretical calculations showing the higher likelihood of forming multilayered Ti2NTx structures during the preparation process in comparison to single-layered structures. As a result of our experimental work, we successfully synthesized multilayered Ti2NTx MXene that was suitable for biological studies by the etching of the Ti2AlN MAX phase and further delamination. The biocompatibility of Ti2NTx MXene was evaluated in vitro towards human skin malignant melanoma cells, human immortalized keratinocytes, human breast cancer cells, and normal human mammary epithelial cells. Additionally, the potential mode of action of 2D Ti2NTx was investigated using reactive oxygen tests as well as SEM observations. Our results indicated that multilayered 2D sheets of Ti2NTx showed higher toxicity towards cancerous cell lines in comparison to normal ones. The decrease in cell viabilities was dose-dependent. The generation of reactive oxygen species as well as the internalization of the 2D sheets play a decisive role in the mechanisms of toxicity.ConclusionsWe have shown that 2D Ti2NTx in the form of multilayered nanoflakes exhibits fair stability and can be used for in vitro studies. These results show promise for its future applications in biotechnology and nanomedicine.

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.

Polypropylene (PP) is a thermoplastic polymer widely used as a medical textile in healthcare applications due to its low cost and superior performance. However, it does not show antibacterial properties leading to the possibility of pathogen transmission. Herein, we have developed an antibacterial medical fabric by facile self-assembly of delaminated two-dimensional (2D) Ti 3 C 2 T x MXene flakes bristling on the surface of PP fibers. The increasing amount of MXene in the coating solution from 1 up to 32 mg/mL allowed for edge-on assembly of MXene flakes on the PP surface and tracking the evolution of the band gap for a restacked structure. Characterization of the PP/Ti 3 C 2 T x nanocomposite has proven that it exhibited highly effective antibacterial, robust coating, and chemically/thermally stable properties. The in vitro microbiological studies against Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus have shown that PP/Ti 3 C 2 T x reduced the bacterial viability up to 100%, as driven by synergistic membrane stress mediated by physical contact and light-induced reactive oxygen species (ROS) generation. Moreover, the use of L-ascorbic acid for MXene stabilization allowed for achieving excellent thermal stability of the PP/Ti 3 C 2 T x nanocomposite upon accelerated thermal aging. Collectively, this work provides a facile surface engineering strategy for designing medical fabrics with outstanding functional performances. By demonstrating the exceptional performance of the stabilized MXene in a self-assembly nanocomposite structure, we are opening the door for MXenes to be applied in other biomedical fields.

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This paper discusses the influence of Ti3C2 (MXene) addition on silicon nitride and its impact on the microstructure and mechanical properties of the latter. Composites were prepared through powder processing and sintered using the spark plasma sintering (SPS) technic. Relative density, hardness and fracture toughness, were analyzed. The highest fracture toughness at 5.3 MPa·m1/2 and the highest hardness at HV5 2217 were achieved for 0.7 and 2 wt.% Ti3C2, respectively. Moreover, the formation of the Si2N2O phase was observed as a result of both the MXene addition and the preservation of the α-Si3N4→β-Si3N4 phase transformation during the sintering process.