Antibacterial composite hybrid coatings of veterinary medical implants.

The aim of the work was to develop innovative antibacterial hybrid coatings applied on implants that are used for anastomoses of animals' long bones and to assess their physicochemical and biological properties. Plates made of the titanium alloy were covered with composite hybrid layers so as to protect the implant surface against corrosion and to enhance it with antibacterial properties.The hybrid coatings were obtained electrochemical oxidation and sol-gel. First, a layer of titanium nanotubes was applied to the implants surface through anodization. Next, the sol-gel method was used to create the second layer with silver nanoparticles. The microstructure examination of the materials was performed with the SEM. The phase composition analysis was carried out via the X-ray diffraction. The surface parameters (roughness, contact angle and free surface energy) were assessed. Biological studies of implants were conducted, including the analysis of degradation processes, cell response and bactericidal activity. The results confirmed that the hybrid antibacterial layers effectively protected the implant surface against scratches and corrosion and eliminated bacteria, which in turn would promote bone healing. The advantageous physicochemical and biological properties of metallic implants with hybrid composite layers raise hopes for their applicability in the veterinary treatment of bone fractures.

Biopolymeric hydrogels - nanostructured TiO2 hybrid materials as potential injectable scaffolds for bone regeneration.

The present work aims at development of novel hybrid materials from genipin crosslinked collagen or collagen/chitosan hydrogels containing various types of TiO2 nanoparticles characterized with different anatase/rutile ratios. Collagen and chitosan were selected as hydrogel components since they are biopolymers being, like collagen, the major compound present in extracellular matrix or exhibit structural similarity to glycosaminoglycans, like chitosan. TiO2 nanoparticles were introduced to the hydrogel matrices to improve their mechanical properties as well as bioactivity. A series of twelve novel hybrid materials were prepared and their physicochemical, mechanical and biological properties were evaluated. It was found that TiO2 nanostructures introduced to the hydrogels have significant influence on the swelling properties of the synthesized hybrids and their impact is strongly dependent on the type of matrices. The surfaces of hybrid materials were found to be more hydrophilic than these of corresponding hydrogel matrix. It was also observed that, the storage modulus values of the hybrids based on collagen-chitosan hydrogel are comparable to these for plain hydrogels what indicates that the mechanical properties of the materials obtained are satisfactory for possible biomedical application. The in vitro cell culture studies have shown that prepared materials are biocompatible as they can support mitochondrial activity of MEFs as well as MG-63 cells. In vitro experiments performed under simulated body fluid (SBF) conditions have revealed that all studied TiO2 nanoparticles present in hydrogel matrices, regardless of anatase/rutile ratio, successfully induced formation of apatite-like structures. The hybrid materials developed here are promising candidates for preparation of bioactive, injectable scaffolds for tissue engineering.