Plasma, serum, albumin, and divalent metal ions inhibit the adhesion and the biofilm formation of Cutibacterium (Propionibacterium) acnes.

Adhesion and biofilm formation of human skin bacteria C. acnes on plasma, serum and albumin-coated polystyrene or in the presence of these blood components were studied. The proteins which were pre-adsorbed to polystyrene surface or added to the medium simultaneously with bacterial cells reduced C. acnes adhesion and biofilm formation by 2-5 times to compare to the control. The role of calcium, magnesium and zinc on C. acnes attachment was also assessed. Calcium (1 and 10 mM) had the inhibitory effect on C. acnes adhesion, whereas zinc (1 and 10 mM) diminished the biofilm formation of C. acnes. We also observed that C. acnes cells did not bind to erythrocytes. Thus, we suggest that bacteria C. acnes preferably colonize the plasma-poor environment due to the inhibitory effect of blood components, in particular, albumin, calcium, and zinc.

Structural-mechanical and antibacterial properties of a soft elastic polyurethane surface after plasma immersion N2(+) implantation.

The surface of elastic polyurethane treated by plasma immersion N2(+) ion implantation at different fluences has been investigated. A folded surface structure is observed in all cases. Analysis has been performed to study the structural (roughness, steepness and fraction of folds, fractal characteristics), mechanical (stiffness, adhesion force between the AFM probe and the material) and wetting properties of surfaces. Under uniaxial stretching the cracks orthogonal to the axis of deformation and longitudinal folds are formed on the examined surfaces. After unloading the initial structure of the surface of deformed materials exposed to low fluences becomes smoother and does not recover, i.e. it has plastic properties. By contrast, the structure of the surfaces of materials subjected to high-fluence treatment recovers without visible changes and the cracks are fully closed. The study of Staphylococcus colonies grown on these materials has demonstrated significant reduction (from 3 to 5 times) in the vitality of bacteria on treated surfaces. This result was repeated on samples after 11 months of storage. Such antibacterial properties are primarily related to the structural changes of the surfaces accompanied by the increased hydrophilicity.