Calcium alginate/graphene oxide films: Reinforced composites able to prevent Staphylococcus aureus and methicillin-resistant Staphylococcus epidermidis infections with no cytotoxicity for human keratinocyte HaCaT cells

The rapid emergence of drug resistance in pathogenic bacteria is becoming a serious global public health problem. Therefore, there is an imminent need of finding new alternative antibacterial approaches which are cost-effective and able to impede multi-drug resistant infections. Alginate is a low-cost material in comparison with other biopolymers, it is renewable and it possess excellent hydrophilicity, biocompatibility and biodegradability. Thus, in this study, alginate composite films were produced with calcium chloride as cross-linker and several low graphene oxide (GO) contents ranging from 0 to 1% w/w. These composites were tested against two clinically relevant pathogens, one of them multidrug-resistant, Staphylococcus aureus and methicillin-resistant Staphylococcus epidermidis, by two complementary antibacterial methods. The results of this study showed that the incorporation of a low amount of GO (0.5% w/w) can produce compression reinforced calcium alginate films with a low reduction of transparency and very high antibacterial activity against these two life-threatening pathogens. Furthermore, none of the extracts of these hydrophilic composite films caused any statistically significant cytotoxic effect in the presence of human keratinocyte HaCaT cells, which render these low-cost composites very promising for many bioengineering applications such as tissue engineering, wound healing and drug delivery systems.