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Synthesis and Mechanical Properties of a Biocompatible Chitosan-Graphene Oxide Nanocomposite for Tissue Engineering

Mazaheri, Mozhdeh | 2013

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 44147 (07)
  4. University: Sharif University of Technology
  5. Department: Materials Science and Engineering
  6. Advisor(s): Simchi, Abdolreza; Akhavan, Omid
  7. Abstract:
  8. Chitosan (CS) is a natural polysaccharide, which is widely used for various biomedical applications due to its excellent properties such as biocompatibility, biodegradability, bioadhesivity, and bactericidal capacity. Nevertheless, the poor mechanical strength and the loss of structural integrity limit the applications of chitosan. Graphene oxide (GO) has been recognized as an ideal filler for reinforcement of a polymer matrix and its excellent water solubility makes it as a promising candidate for biopolymers. In this work, biocompatible chitosan-graphene oxide nanocomposites were synthesized. First, graphene oxide was prepared using modified Hummer’s method from graphite powder. Solvent casting procedures were then utilized to prepare CS-GO composite films. The effect of the GO content (0, 1.5, 3, 6 in wt.%) on the mechanical properties of the films was investigated using uniaxial tensile test at ambient temperature. It was shown that the addition of GO improves the strength of chitosan significantly. For instance, the fracture strength and elastic modulus of a chitosan-6 wt.% GO nanocomposite were 72% and 43% higher than those of the unreinforced chitosan, respectively. We showed that the enhanced strength is attributed to the strong interfacial adhesion between GO and chitosan as carboxylic and hydroxyl groups of GO nano-sheets interact with the chitosan matrix. We also examined the antibacterial activity of CS-GO against S. aureus by the colony counting method. Results confirmed that the nanocomposites possess bactericidal capacity, e.g., in the presence of 6 %wt GO bacterial growth inhibited over 80%. Contact angle measurements and AFM results showed that the addition of GO increased the surface roughness and wettability of the films and thus affected their cellular behavior. Culturing of stem cells (hMSCs) and the viability assay using the fluorescein diacetate (FDA) method determined cytocompatibility of graphene oxide. Therefore, the synthesized nanocompsites with enhanced tensile properties, antibacterial activity and cytocompatibility could be a promising material for biomedical applications
  9. Keywords:
  10. Graphene Oxide ; Chitosan ; Nanocomposite ; Mechanical Properties ; Biocompatibility

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