Introduction: Modern scientific and clinical data indicate that 60% of chronic wounds contain microbial biofilms, which are associated with the main pathophysiological processes and contribute to the prolongation of infection. The nitric oxide (NO) radical, depending on application time and concentration, has been shown to cause the dissolution of biofilms and sensitization of bacteria to antibiotics without causing resistance. In nanomolar concentrations, NO stimulates vasodilation, enhances the proliferation of endothelial cells, reduces thrombus formation, and promotes angiogenesis and wound healing. Therefore, research and development of the immobilization of nitric oxide precursors on carriers for local delivery of controlled amounts of NO for specific medical purposes is relevant.

Methods: The deposition of plasma polymers was carried out using a ZP-COVANCE-RFPE-3MP vacuum system equipped with an oil diffusion pump providing the residual pressure in a vacuum chamber below 30 Pa. Isopentyl nitrite (99.995%) and C2H4 (99.95%) were used as precursors to deposit thin films on silicon wafers and polycaprolactone nanofibers at a discharge power of 30 W. The obtained plasma-deposited polymer films were studied by SEM, EDX analysis, XPS, FTIR spectroscopy, and WCA. The films were tested against different pathogens.

Results: Plasma deposition resulted in homogeneous and well-bonded layers. SEM micrographs showed no pinholes, cracks, or other damage in the deposited layers. According to FTIR and XPS, the obtained spectra indicated the presence of nitroxyl compounds on the surface of samples. It was shown that nitroxyl-containing films prevented the formation of biofilms.

Conclusions: We developed an approach to deposit nitroxyl-containing films from a mixture of isopentyl nitrite/C2H4 and demonstrated antibacterial effects against Gram-positive and Gram-negative pathogens.

This work was supported by the Russian Science Foundation (grant №20-19- 00120-P).