Surface treatment of artificial implants with hybrid nanolayers: results of antibacterial tests, leachates and scanning electron microscope analysis

The aim of this study was to evaluate the antibacterial efficacy of surface-treated hernia implants modified by a hybrid nanolayer with incorporated Ag, Cu, and Zn cations using the sol-gel method. The materials (polypropylene, polyester, and polyvinylidene difluoride) were activated by vacuum plasma treatment or UV C radiation, then modified and tested for bacterial strains of (gram-negative) and (gram-positive). The AATCC 100 (2019) method for quantitative and the ISO 20645 agar plate propagation method for qualitative evaluation of microbiological efficacy were used. The gradual release of incorporated ions was monitored over time in simulated body fluids (blood plasma, peritoneal fluid) and physiological saline using an inductively coupled plasma mass spectrometer. The thickness and the homogeneity of the layers were measured for individual random samples with scanning electron microscope analysis (SEMA) and evaluated with an elemental analysis. Qualitative and quantitative microbiological tests clearly show the great suitability of vacuum plasma and UV C with sol AD30 (dilution 1:1) surface treatment of the implants. The absolute concentration of Ag, Cu, and Zn cations in leachates was very low. SEMA showed a high degree of homogeneity of the layer and only very rare nanocracks by all tested materials appear after mechanical stress. This study confirms that surface treatment of meshes using the sol-gel method significantly increases the antibacterial properties. The nanolayers are sufficiently mechanically resistant and stable and pose no threat to health.