A novel PGA-chitosan biomaterial fabrication, modification and biomedical applications

• Main Authors: Yu-chi Wang, 王羽淇
• Other Authors: Hsyue-Jen Hsieh
• Format: Others
• Language: en_US
• Published: 2002
• Online Access: http://ndltd.ncl.edu.tw/handle/68334917199354753338

博士 === 國立臺灣大學 === 化學工程學研究所 === 91 === Abstract In recent years, free tissue transfers, which require tissue or organ substitutes to repair/replace the damaged/diseased organs or tissues have been developed. The immediate problem is the shortage in donor availability. To solve this problem, people use the technology of tissue engineering, which elucidates the structure-function relationships in normal and diseased tissues, to create tissue or organ replacements. Biomaterials play an important role in many of these activities, for example, serving as matrices to guide tissue regeneration, releasing polypeptide growth factors and stimulating cellular response to an antificial implant. This study focused on the development of a novel biomaterial, the modification of the biomaterial, and the application of this novel biomaterial. In the first part, a freeze-fixing method was used to prepare a novel porous PGA-chitosan hybrid matrices (P/C matrices) containing 70% of PGA. The P/C matrices prepared at -20℃ have 100-200 m interconnected micropores in the interior region, with a porous layer present on the bottom and top of the matrices. Another set of the P/C hybrid matrices with freezing temperature at -80℃ were also prepared. The pore size of these matrices is 70-80 m. Fibroblast cells cultured on these P/C matrixes exhibited high viability and maintained spindle morphology, suggesting good biocompatibility for the P/C matrices. It can be concluded that the P/C matrices, due to their high porosity, biocompatibility and degradability, are a promising biomaterial. In the second part, I focus to the surface modification of a biomaterial to enhance its function. The use of wheat germ agglutinin (WGA), a commonly used lectin, covalently bound on to chitosan films to improve the biocompatibility and specificity of chitosan films via oligosaccharide-mediated cell adhesion was examined. After seeding for 12 h, the ratio of live fibroblast cells was about 80% on the WGA-modified chitosan films but at the same time only 65% cells were alive on the control chitosan films. The percentage of live cells on the WGA-modified chitosan films and the chitosan films increased to nearly 100% and 85%, respectively, at 48 h after seeding. The DNA staining revealed that a portion of fibroblasts cultivated on the chitosan films were undergoing apoptosis. In contrast, fibroblasts growing on the WGA-modified chitosan films did not show any indication of apoptosis. Further, the evaluation of the heat shock protein (HSP) mRNA expression in the cells using the reverse transcription-polymerase chain reaction (RT-PCR) method indicated that HSP 90 expression was enhanced on the chitosan films and decreased to normal levels on the WGA-modified chitosan films. Taken together, our data suggest that the use of WGA to enhance the cell-biomaterial interaction is a promising way to achieve appropriate cell adhesion and proliferation, the two key issues in tissue engineering. The third part was to address new applications of this novel P/C biomaterial. Endometriosis, a disease that affects many women in reproductive age, is defined as the presence of endometrial tissue outside its normal location. Although treatment options have improved considerably in recent years, but such as unexplained pelvic problems and infertility still remain. In this study, the growth-inhibitory effect of a novel P/C material-based biological spray on endometriosis was evaluated. Flow cytometry analysis reveled that both fractions of early apoptotic and late apoptotic cells increased in the endometrial cells treated with this P/C spray. This is the first trial using the P/C spray to successfully inhibit cell proliferation by inducing apoptosis. Therefore, this novel P/C spray should have great application potential in endometriosis therapy.