Exploring the Antimicrobial Potential of Vanadium-Based MXenes for Biomedical Applications

MXenes, a family of two-dimensional transition metal carbides, carbonitrides and nitrides, have emerged as highly interesting antimicrobial nanomaterials. While mostly Ti-based MXenes have been explored in this field, our work aims at characterizing and investigating the antibacterial and biocompatibility profiles of two vanadium-based MXenes (V₂CTₓ and V₄C₃Tₓ) against Escherichia coli and Staphylococcus aureus, two clinically relevant pathobionts. First, the as-synthesized nanomaterials were chemically and structurally characterized to confirm their morphology and structural integrity. After setting up two distinct experimental models (static and dynamic), the antibacterial activity was evaluated by colony-forming units (CFUs) counting and scansion electron microscopy (SEM). Cellular cytotoxicity was assessed by lactate dehydrogenase (LDH) release and crystal violet characterization (CV). To further evaluate the MXenes' properties, the antimicrobial activity was tested in in-vitro infection models using both epithelial (Caco-2) and macrophage (J774) cells measuring CFUs. To assess the oxidative stress contributing to MXenes' antibacterial activity, reactive oxygen species (ROS) production was valued in infected cells after treatment. V₂CTₓ and V₄C₃Tₓ showed an antibacterial activity concentration and condition dependent. The dynamic incubation improved the bacterial reduction, supporting a "nano-knife" mechanism linked to the physical disruption of the membrane. Finally, V₂CTₓ and V₄C₃Tₓ significantly reduced the intracellular bacterial burden in infected Caco-2 epithelial cells in comparison with macrophages. Importantly, MXenes' treatment did not result in marked ROS stimulation, suggesting that their antibacterial activity mainly arose from physical interactions. Our findings highlight that vanadium-based MXenes have good biocompatibility and are moderately effective antimicrobial nanomaterials, emphasizing the need to use commonly recognized and standardized experimental models to elucidate their potential antimicrobial applications.