Investigating the best strategy to diminish the toxicity and enhance the antibacterial activity of graphene oxide by chitosan addition.

The main objective of this work was to find a way to increase the bio-applicability of graphene oxide (GO) nanoparticles. In this way, various kinds of graphene oxide-chitosan (GO-CS) nano-hybrids were synthesized through attachment of different kinds of chitosan (CS) structures with GO. Subsequently, they were assessed in terms of structural characterization, antibacterial activity and cytotoxicity to obtain a hybrid structure representing the highest bactericidal and biocompatibility performance. Our results revealed that the single-layer GO and also three different kinds of GO-CS nano-hybrid structures (pristine powder, spherical and nano-fibrilar network structures) were successfully synthesized. Antibacterial activity results indicated superior antibacterial activity of nano-hybrids compared to the pure GO. In addition, it was observed that the attachment of CS to GO interestingly reduced the cytotoxicity effect of GO and even caused cell proliferation in some samples. Furthermore, the antibacterial and bio-safety properties of different hybrids were compared and suggestive mechanisms for their particular performances were proposed.