| Summary: | 碩士 === 長庚大學 === 化學工程研究所 === 90 === In this research, we utilize collagen and chitosan as scaffolds for cultivation of liver cells. The pore size of matrices were influenced by the freezing temperature during the preparation step. Collagen matrices prepared at -30℃ give average pore sizes of 60 μm, while chitosan matrices prepared at -20℃ give pore sizes of 100 μm. The collagen matrices were crosslinked by dehydrothermal（DHT） treatment or with a chemical reagent（EDC）. The pores of the matrix were partial collapsed after DHT but remained intact after EDC-crosslinking. Chitosan matrices were crosslinked by genipin（GP） and glutaraldehyde（GA）, the most suitable crosslinking conditions were at 25℃, reaction for 9 hr, and with 0.625% reagent concentration.
Chondroitin sulphate（CS） could be covalently attached to the collagen matrices during crosslinking. Over 100 mg of CS could be attached to collagen per 1 g of collagen matrix. Collagen matrices with or without CS were used in HepG2/C3A cultivation. Cell growth in collagen matrix containing CS were better than that without CS. For liver specific functions, ammonia, urea-N and albumin synthesis rates are higher for cells grown in collagen matrices （with or without CS） than those of cells grown on dishes Collagen matrices also promote cell proliferation and maintain liver specific functions in long time culture.
For chitosan matrices crosslinked by GA, weight loss are higher than those crosslinkied by GP. MTT assay also revealed less cells toxicity for GP-crosslinked chitosan matrices.
The cell loading efficiency approaches 90﹪ when the initial cell loading numbers were below 1×105, and seeding efficiency decreased to 80﹪ for cell density above 1×105 .Rat hepatocyte specific functions decrease with seeding cell number increase, and cells aggregation was observed after cultivation for 1 day in chiotsan-GP matrices. Metabolic functions of hepatocytes for ammonia removal, urea-N and albumin synthesis were better when cells cultivated in chitosan matrices then in dishes.
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