Pristine and antibiotic-loaded nanosheets/nanoneedles-based boron nitride films as a promising platform to suppress bacterial and fungal infections

In recent years, bacteria inactivation during their direct physical contact withsurface nanotopography has become one of the promising strategies for fighting infection. Contact-killing ability has been reported for several nanostructured surfaces, e.g. black silicon, carbon nanotubes, zinc oxide nanorods, and copper oxide nanosheets. Herein, we demonstrate that Gram-negative antibiotic-resistant Escherichia coli (E. coli) bacteria are killed as a result of their physical destruction while contacting nanostructured h-BN surfaces. BN films, made ofspherical nanoparticles formed by numerous nanosheets and nanoneedles with a thickness 99 % inactivation of colony forming units after 24 h, same as gentamicin-loaded (150 µg/cm2) BN sample. The BN films loaded with a mixture of gentamicin (150 and 300 µg/cm2) and amphotericin B (100 µg/cm2) effectively inhibit the growth of E. coli K-261 and Neurospora crassa strains. During immersion in the normal saline solution, the BN film generates reactiveoxygen species (ROS), which can lead to accelerated oxidative stress at the site of physical cell damage. The obtained results are valuable for further development of nanostructured surfaces having contact killing, ROS and biocide release abilities