Preparation and Biological Activity of New Collagen Composites Part II: Collagen/Reduced Graphene Oxide Composites

With the idea of exploring the biological activity of some newly synthetized chemical compounds and their combinations for development of novel antimicrobial collagen biomaterials, a serial investigation was initiated, starting with the preparation and biological activity study of Collagen/ZnTiO₃ nano-composites. This serial investigation continued with the preparation and biological activity study of new collagen-based composites in which self-prepared reduced graphene oxide (RGO) sheets were included as an antimicrobial agent. The new porous collagen/RGO composites demonstrated specific antimicrobial activity to different types microbial species; well pronounced activity against Gram-positive microorganisms (Listeria innocua and Bacillus cereus, both bacteria with typical chains forming, large size cells, and Candida lusitaniae, fungus with specific micelle organization) and lack of activity against Gram-negative bacteria (Pseudomonas putida, Salmonella enterica, Pseudomonas aeruginosa, and Escherichia coli; all bacteria with small size cells) combined with lack of cytotoxicity to eukaryotic cells. For the first time, well-pronounced antifungal activity of collagen/RGO composites, depending on the RGO concentration was observed. Sterile zone of 17 mm was measured for C. lusitaniae on collagen/RGO composite, 2:1 wt/wt. The possible mechanism of the biological activity of the new collagen/RGO composites was correlated with their characteristics and the specific cell morphology and size of the test microorganisms. The results of this investigation demonstrated that with their specific and adjustable bioactivity, the new collagen/RGO composites are promising antimicrobial biomaterial for variety of biomedical applications, including tissue engineering.