Zn-doped and Cu-doped SiO_x films were synthesized by atmospheric pressure plasma chemical vapor deposition to study their antibacterial efficiency against Gram-negative Escherichia coli and their cytotoxic effect on the growth of mouse cells. Zn-rich and Cu-rich particles with diameters up to several microns were found to be homogeneously distributed within the SiO_x films. For both doping elements, bacteria are killed within the first three hours after exposure to the film surface. In contrast, mouse cells grow well on the surfaces of both film types, with a slight inhibition present only after the first day of exposure. The obtained results indicate that the films show a high potential for use as effective antibacterial surfaces for medical applications.

In this study, assessment of the antimicrobial activity of a novel, plasma-cured 2.5% (w/v) Cu(NO₃)₂-containing sol–gel surface was performed. In contrast to state-of-the-art sol–gel coatings, the plasma curing led to a gradient in cross-linking with the highest values at the top of the coating. As a result, the coating behaved simultaneously hard, scratch-resistant, and tough, the latter due to the more flexible bulk of the coating toward the substrate. Further, the diffusion and permeation through the coating also increased toward the substrate. In our study, tests according to ISO 22196 showed antibacterial activity of the 2.5% (w/v) Cu(NO₃)₂-containing sol–gel surface against all bacterial strains tested, and we expanded the testing further using a “dry” evaluation without an aqueous contact phase, which confirmed the antimicrobial efficacy of the 2.5% (w/v) Cu(NO₃)₂-containing sol–gel surface. However, further investigation under exposure to soiling with the addition of 0.3% albumin, used to simulate organic load, led to a significant impairment in the antibacterial effect under both tested conditions. Furthermore, re-testing of the surface after disinfection with 70% ethanol led to a total loss of antibacterial activity. Our results showed that besides the mere application of an antimicrobial agent to a surface coating, it is also necessary to consider the future use of these surfaces in the experimental phase combining industry and science. Therefore, a number of tests corresponding to the utilization of the surface should be obligative on the basis of this assessment.