Microstructure and antibacterial properties of a ZnO coating on a biomaterial surface

A promising strategy for fighting the bacterial biofilm on the surface of biomaterials involves modification of their surface with the use of bactericidal and bacteriostatic coatings. Ongoing studies concentrate on the development of material that can limit bacterial colonisation and is safe for the human organism. Therefore, the current research focuses on the conditions related to implant coating to limit biofilm formation. However, previous outcomes in this area have not been satisfactory. Accordingly, the main goal of the carried out tests was to study the impact of the physicochemical properties of the surface layers on the course of processes taking place on the surface of implants made of metallic biomaterials used in the bone system. The surface of the analysed biomaterial-316LVM steel-was modified using such processes as grinding, electrochemical polishing, sandblasting, application of a ZnO layer using low-temperature Atomic Layer Deposition (ALD), and medical sterilisation. Initial assessments involved the chemical composition, phase composition, and the microstructure of the surface layer. The last stage involved microbiological studies, including an assessment of the adhesion of Gram-positive and Gram-negative bacteria to the modified surface, proliferation of MG-63 osteoblast-like cells and cytotoxicity tests. The analysis of adhesion of S. aureus and E. coli colonies confirmed that the ZnO coating is effective in reducing bacterial adhesion to the 316LVM steel substrate, regardless of the number of cycles, process temperature and surface treatment method.