Introduction: Bacterial adhesion represents a physicochemical process which occurs when cells (bacteria) are bound to the substrate. Bacteria attached to medical devices and implants may cause many infections that can be dangerous to humans. By coating surfaces bacterial adhesion and consequent biofilm formation can be reduced. Purpose: The purpose of this thesis is to change the surface of stainless steel AISI 316 by coating with different coatings and to determine the effect of coating on bacterial adhesion Psudomonas aeruginosa. Working methods: In diploma thesis a descriptive and a research method were used. For the research we used electropolishing tiles of stainless steel AISI 316 in size 10 mm × 10 mm, which we coated with coating Funcosil AG, Funcosil SNL and Si-QAC. Both tiles, coated and non-coated, were exposed to the bacterial culture Pseudomonas aeruginosa. At time t0 and after twenty hours of incubation (t20), we detected the presence of bacteria on surfaces by dyeing with crystal violet dye, iodo-nitro-tetrazolium chloride and sonication. Contact angles and surface roughness were measured for all four tiles groups. Tiles with bacterial culture intended for analysis by Scanning Electron Microscope were evaporated with carbon, analysed and the number of attached bacteria was estimated. Results: Uncoated tiles have the least rough surface. Funcosil AG-coated tiles proved the roughest surface. The minimum limit angle (82,6°) was measured in uncoated tiles, followed by SI-QAC coated tiles, where the limit angle was 92.8°. An even higher limit angle (105,7°) was measured in Funcosil SNL-coated tiles and the highest angle was measured on Funcosil AG-coated tiles (111,5°). All three coatings thus proved to be hydrophobic. With the Scanning Electron Microscope analysis, bacteria were visible at time t0 and t20 only on Si-QAC-coated tiles, no bacteria were present on the other groups of tiles. The average number of live bacteria obtained by colony counting units (CFU) was lower at time t0 and time t20 on coated tiles compared to uncoated tiles. The average number of bacteria after staining with crystal violet dye, showing both live and dead bacteria, was higher on the coated tiles. Discussion and conclusion: We proved that coatings affect bacterial adhesion and survival on surfaces.
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