| Summary: | 碩士 === 元智大學 === 化學工程與材料科學學系 === 99 === Polyhydorxyalkanoates (PHAs) is a biodegradable plastic that can be produced and/or decomposed by microorganism. PHAs possess material properties which are similar to those of petroleum polymer. Thus, PHAs have been known to be biodegradable and biocompatible, it seemed to be a promising alternative in place of traditional plastics for various applications. These properties make them good candidate for possible applications as medical. The purpose of this research is to estimate the probavility of application of PHAs in hernia repaired membrane.
In this study, poly(3-hydroxybutyrate) (PHB) was generated via fermentation in our lab, and commercial available oly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) purchased from Sigma-Aldrich Chemical Co., USA, were used for this feasibility testing. First, the effect of thermal treatment on characteristics of PHAs was investigated. Then, the membranes made from PHAs were tested as the material for the hernia repaired in mice. To compare the cost-effectiveness of our produvts, commercial hernia repaired membrane of polypropylene (PP) purchased from Bard Co., USA, were used as a control material.
By using XRD, when the temperature increased from 130 oC to 150 oC the crystallinity profiles of PHAs were increased with the raising temperature and the holding time. However, the crystallinity was decreased at 180 oC for a holding time of 10 min. The crystal plane (101) and (111) were also shown that the crystal morphology was changed. Meanwhile, the molecular weight (Mw) of PHAs decomposed rapidly according to GPC analysis. This result apparently explained the significant decrease in crystallization of PHAs at 180 oC was due to a noteworthy decrease in molecular weight. It is also observed that the no peak signal was found in GPC after heating at 150 oC. It can be attributed the solubility changed to increase the crystallinity of PHAs.
In the study of application of hernia membrane, this research removed endotoxin of PHAs and designed the model for hernia in mice successfully. The result shows that the endotoxin unit was decreased from 21,100 (EU/gPHA) to less than 0.001 (EU/gPHA) after removal of endotoxin process. After removing endotoxin, the cells can grow and proliferate well in PHAs membranes. The relative surface cell density of PHAs is 0.5. It means that the PHB and PHBV membranes which are endotoxin free have good biocompatibility. The membranes were tested in vivo to evaluate the immune response. The result shows that the PHAs mambranes does not cause the terribly immune response. In the pictures of tissue, it was observed that the PHB membrane is more slowly degradable than PHBV membrane. The adhesion ratio of PHB membrane is also smaller than those of PHBV and PP membrane. It shows PHB is suitably used in hernia repaired membrane. .
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