Mxene-Based Photothermal Ablation of Staphylococcus Aureus and Candida Albicans

Introduction. Exploitation of photo-thermal abilities of MXenes has shown promising results in the fight against bacterial infections, including antibiotic-resistant strains[1]. MXenes can be activated by near-infrared light (NIR) absorbing laser light and converting it into heat, which can then be used to destroy microorganisms[2]. This light triggers a dual attack: it heats the microbes while simultaneously sharpening the MXene's edges, allowing them to pierce and disrupt the microbial cell membrane. Photothermal technology has the potential to address the challenge of antibiotic resistance and provide more effective treatment options for microbial infections[3].

Aim. Our research focuses on elaboration of the optimal MXene’s concentration that delivers the most effective antimicrobial photothermal therapy when combined with appropriate laser irradiation mode.

Materials and methods. To compare the effectiveness of the Ti3C2 MXene as a photothermal agent (PTA) against different microorganisms (Staphylococcus aureus and Candida albicans at a concentration of 10⁵ colony-forming units per milliliter, CFU/ml), we used MXene suspensions (at concentrations of 0.44 mg/ml and 0.044 mg/ml). Mixtures of microbial suspension and MXene in equal amounts were cultivated for 4 h at 37°C followed by laser exposure for 10 minutes using a setting of 2 W and 10 Hz. The Petri dishes with nutrient media were inoculated with aliquots of the mixture and incubated for 24 hours at 37°C. Evaluation of results was represented in CFU/ml compared to non-treated samples.

Results. MXenes, as PTA, demonstrated remarkable success against C. albicans at both tested concentrations, completely eliminating the fungus. S. aureus was less sensitive to laser exposure, and noticeable microbial growth retardation was observed only at MXene concentration of 0.44 mg/ml. The varying responses of bacteria and fungi to MXene-based photothermal therapy (PTT) can be attributed to differences in its cell wall composition and susceptibility to heat. Moreover, the absence of a significant impact on fungal or bacterial growth in samples treated with MXene alone (without laser exposure) underscores the importance of thermal activation in achieving antimicrobial effects, highlighting the selective nature of MXene-based PTT against different microorganisms.

Conclusion. MXene has the potential to become a groundbreaking weapon against microbial infections. To fully utilize this potential, additional studies are essential to establish a precise protocol for antimicrobial PTT that involves determining factors like the irradiation mode, intensity, and exposure time, taking into account that the cell wall structure and thermal tolerance of bacteria differ from those of fungi, influencing their responses to PTT.