Study On The Preparation And Antibacterial Properties Of Graphene Oxide Coatings

Silicone rubber is widely used as implant materials due to its excellent chemical stability,physiological inertia and aging resistance.But the surface of silicone rubber is prone to bacteria adhension and the formation of biofilm,leading to infection and complications.Antibacterial coating was a simple and effective way to provide the silicone rubber substrates with antibacterial performance.However,the commonly used antibacterial agents,such as silver icons,have potential risk of cell toxicity as well as effective antibacterial activity.To obtain safe and effective antibacterial coatings,graphene oxide was used in this study and grafted onto substrates surface to form the antibacterial coatings.Firstly,ultraviolet radiation was employed to generate active groups on the surface of silicone rubber,followed by the grafting of silane coupling agents(3-Mercaptopropyl)trimethoxysilane(MPTS).The MPTS was served as bridge moleculars to bond graphene oxide onto modified substrates to form the antibacterial coatings.Besides,to enlarge the specific surface area of graphene oxide,the nanostructured graphene oxide was obtained by using the lyotropic liquid crystalline templates,and the nanostructured graphene oxide coatings was resultantly prepared.Raman spectroscopy and small angle X-ray scattering are used to analyze the graphene oxide coatings,scanning electron microscopy(SEM)is employed to observe the morphology,contact angle measurement instrument is applied to test the wettability.Polarizing microscopy and low angle X-ray diffraction are used to analyze the structure of lyotropic liquid crystal,low angle X-ray diffraction and transmission electron microscopy(TEM)are employed to analyze the nanostructure of nanostructured graphene oxide.The antibacterial properties of the coatings were tested by plate colony-counting methods and fluorescent staining method.The LIVE/DEAD viability /cytotoxicity kit is used to detect the death of cells and the cytotoxicity of the coatings to endothelial cells.The results are as follows:(1)The ultraviolet radiation activation and siliane coupling agents modification bonded graphene oxide onto the surface of silicone rubber and formed antibacterial coatings.(2)The graphene oxide coatings showed antibacterial activity against E.coli and S.aureus,which may come from oxidative stress of graphene oxide,not just physical damage.(3)The graphene oxide coatings showed no obvious cytotoxicity to endothelial cells.(4)The lamellar and hexagonal nanostructured graphene oxide were prepared by using lyotropic liquid crystal soft template.(5)Compared with the graphene oxide,the nanostructured graphene oxide coatings showed stronger antibacterial activity.