Research Of Peptide Modified Graphene Oxide Material And Its Application

Graphene oxide(GO) is a novel two–dimensional planar nanomaterial consisting of rings of carbon atoms. This unique nanocarbon material with outstanding physical, chemical, mechanical and electrical properties is a promising material for biomedical applications. However, its antibacterial property, which affects by various factors such as concentration, size and functional groups, is not stable. This disadvantage and its potential cytotoxicity limit the practical applications of GO as biomedical material. Peptide is a compound that formed by peptide bonds linked α-amino acids. RGD peptide commonly used to improve the biocompatibility of materials. Antimicrobial peptide(AMP) with broad-spectrum antimicrobial activity doesn’t cause bacterial resistance. For the purpose of solving the problems mentioned above, a facile and efficient chemical method(click chemistry) to graft short peptides onto the surface of GO was reported here. Additionaly, the electrospinning was employed to prepare surface-modified GO and polycaprolactone(PCL) co-spinning nano fiber membrane materials.We prepared GO through the improved Hummers’ method which using KMnO4 and H2SO4 as oxidant. Alkyne groups were conjugated onto GO by reacting with silane coupling agent. With click sites, AMP or RGD can be grafted onto the surface of GO nanosheets via CUAAC click reaction catalyzed by Cu(Ⅰ). The achieved materials were characterized using Raman, FTIR, XPS, AFM and TEM. Besides, the cytocompatibility and antibacterial properties of modified GO were investigated. According to the results of cell viability assay, the cytotoxicity of GO significantly reduced after grafted with RGD peptide. The pristine GO showed negligible antibacterial effect comparing with the blank group. On the contrary, nearly 80% of bacteria have been killed by GO grafted with AMP.Electrospun was used to prepare surface-modified GO and PCL co-spinning nanofiber membrane materials with antimicrobial property. Surface morphologies of the membranes were observed using SEM and TEM. ATR, Raman, DSC and TGA were used to characterize the membranes. The antimicrobial results showed that the modified GO fixed on PCL nanofibers still has antimicrobial activity against E. coli and S. aureus with the antibacterial rate of 60% and 50%, respectively. According to the results of cell viability assay, NIH-3T3 cells spread and proliferate well on the surface of the as-prepared electrospun nanofiber membranes, with no difference to the blank group. Those results showed the possibility of using the modified GO as a low toxic and antibacterial material for biomedical.