Preparation and Biological Activity of New Collagen Composites, Part III. Collagen/(Ag/RGO) and Collagen/(Ag/RGO/SiO2) Composites

The aim of this study is preparation, characterization, and biological activity evaluation of 2 new collagen composites, Collagen/(Ag/RGO) and Collagen/(Ag/RGO/SiO₂) with expected antimicrobial activity. The loading of collagen matrix by self-prepared Ag/RGO and Ag/RGO/SiO₂ was varied. The morphology of these antimicrobial agents, as well as of the corresponding collagen composites, was observed by SEM. Their biological activity was evaluated against 3 Gram-negative and 3 Gram-positive microbial strains, as well as against 3 type eukaryotic cells: osteoblast, fibroblast, and epithelial. Dependent on the concentration of Ag/RGO, well pronounced activity against Gram-negative bacterium (E. coli), fungus (C. Lusistaniae) and 2 Gram-positive bacteria (S. epidermidis and B. cereus) was found for Collagen/(Ag/RGO) composites at weight ratios of 2:1, 2:0.8, and 2:0.6, at the last one accompanied by low cytotoxicity. Dependent on the concentration of Ag/RGO/SiO₂ biological activity was found for the Collagen/(Ag/RGO/SiO₂) composites also, better expressed than that of Collagen/(Ag/RGO) composites with the same level of antimicrobial agent loading. The experimental results demonstrated that the doping of RGO with Ag nanoparticles increases the antimicrobial activity of the Collagen/(Ag/RGO) composites. Improving its dispersion, the silane matrix in the Ag/RGO/SiO₂ additionally increases the biological activity of the studied Collagen/(Ag/RGO/SiO₂) composites and their well-pronounced, broad spectrum (against 3 Gram-negative, 2 Gram-positive bacteria and a fungus), antimicrobial activity is similar to that of the broad spectrum antibiotics. The novel Collagen/(Ag/RGO) and Collagen/(Ag/RGO/SiO₂) composites are promising antimicrobial collagen biomaterials that widen the assortment of such for variety biomedical applications.