Thesis (Ph.D.) - Cairo University - Faculty of Science - Department of Biophysics

Graphene oxide (GO) and reduced graphene oxide (rGO) hold great promise for enormous potential in biological applications because of their biocompatibility, unique structure and relatively low cost. The GO was obtained in this work by using graphite as starting material by a modified Hummers and Offeman{u2019}s method. Functionalization of GO and rGO sheets by Polyvinylpyrrolidone (PVP) polymer followed by decorating the sheets with silver nanoparticles ~5 nm (AgNPs) was successfully achieved in order to enhance its antimicrobial activity and biocompatibility. The structural characterizations were performed by Ultraviolet-visible (UV-VIS), Fourier transform infrared (FTIR), Raman spectroscopy and X-ray diffraction. The surface morphology will be shown by High Resolution Transmission Electron Microscopy. The antimicrobial activity of Graphene oxide-silver (GO-Ag), functionalized graphene oxide-silver (FGO-Ag) and functionalized reduced graphene oxide silver (FrGO-Ag) was investigated against Gram positive (Staphylococcus aureus), gram negative (Pseudomonas aeroginosa) bacteria and fungi (Candida ablicans) using colony counting method. The antimicrobial results reveals that the decoration of GO, FGO and FrGO with 5 nm AgNPs improved the antimicrobial activity of these materials (100 og/ml) to 90.5 %, 96 % and 100 %, respectively. The cytotoxicity and cell viability of the prepared materials were tested against BJ1 normal skin fibroblasts. Results revealed that functionalization of GO, rGO, and rGO-Ag increased their biocompatibility (64.4 %, 52.5 % and 88 %) besides to its high antimicrobial activity. It could be concluded that FGO-Ag and FrGO-Ag could be promising as biocompatible antimicrobial materials for burn wound treatment

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