| Summary: | 博士 === 元智大學 === 化學工程與材料科學學系 === 106 === Polyhydroxyalkanoates (PHAs) are biodegradable and biocompatible plastic materials produced by microorganisms with biomedical productions. For tissue engineering. Among PHA composites, poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) polymer demonstrates better mechanical properties and processability. Thus, the purpose of this research work was to explore the fabrication of PHAs polymer obtained from Ralstonia eutropha H16 using both solvent casting and electrospinning approaches. This is followed by surface modification with plasma treatment as to improve the surface properties of the material. The performance of the plasma-treated films for regenerative medicine and tissue engineering could be evaluated by their performance of adipose-derived stem cells (ASCs) on membrane. This study was designated to be 3 portions.
Firstly, the strain R. eutropha H16 was used for culture to investigate the performance of cell growth and PHAs synthesis with various optimized parameters. The optimal culture conditions were 72 hours of culture duration, 5% (w/v) of crude glycerol, 7.5 g L-1 sodium propionate with its adding time after 12 hours of cultured period, 0.2 g L-1 of yeast extract and O2 supplied as inlet culture gas. The PHBV polymer with different 3-HV contents were analyzed by nuclear magnetic resonance (NMR) spectroscopy. The NMR spectra confirmed with literature were identified to be PHBV. In addition, basic physical and chemical properties (e.g., molecular weight and identification of PHBV functional groups) were analyzed. The results suggested that PHBV owned better thermal stability when compared to PHB, and its crystallinity decreased with increased 3-HV content.
Subsequently, two different approaches, namely solvent casting and electrospinning were used to fabricate the polymer films. The surface modifications were performed using plasma treatment of methane/oxygen (CH4/O2) and 1,1,1,2-tetrafluoroethane (C2H2F4) in order to enhance hydrophilicity and hydrophobicity properties, respectively. Moreover, analyses of scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Fourier transforms infrared (FTIR) spectroscopy and water contact angle were carried out. Our results revealed in an improvement of the surface properties like hydrophilic, hydrophobic and roughness as well as the presence of new functional groups of the plasma-treated films, owing to the high-energy of plasma surface activation.
Lastly, in vitro cellular studies of ASCs on the plasma-treated and untreated film were evaluated. Evidently, electrospun CH4/O2-treated PHBV film (hydrophilic PHBV) exhibited better cell proliferation and wound repairing function than the others. This work concluded that PHBV membrane showed better biocompatibility than that of PHB to facilitate cell growth. In addition, plasma surface treatment technology can effectively enhance cell growth on modified PHBV membranes. The combination of these two can be beneficial to the development and application of biomedical materials.
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