Tomoaki Kawai

PREPARATION OF THE HONEYCOMB PATTERNED POROUS FILM OF BIODEGRADABLE POLYMER FOR TISSUE ENGINEERING SCAFFOLDS

Fabrication and surface modification of a cell scaffold are very important in tissue engineering. In this study, the effects of pore size and surface wettability on hepatocyte adhesion and morphology was studied, using the porous poly-e-caprolactone (PCL) film prepared by a simple casting technique. The degree of spreading of hepatocyte was enhanced with the decrease of the pore size (~10 μm). Hepatocyte motility and spreading were restricted on the patterned film having cellular-sized pores (ca. 20 μm). Partial hydrolysis of the film surface enhanced the migration and spheroid formation of the cultured hepatocyte.

Maintenance of morphology and function of mixed liver cell spheroids under collagen gel environment

Mixed liver cell spheroids from rats consisting of hepatocytes and nonparenchymal cells lose three-dimensional structure and function when cultured on dishes. In order to maintain the configuration and function of the spheroids, we cultured them with collagen gel in various conditions, such as on the surface of collagen gel (group 2), between two collagen gel layers (group 3), and within collagen gel (group 4). Spheroids cultured on a standard collagen-coated dish were used as controls (group 1). Culture was continued for 10 days. Phase-contrast microscopy revealed that the spheroids of group 1 lost their spheroidal configuration and became a monolayer within 24 h. Group 2 spheroids also spread out to a monolayer, but thus occurred at 24 to 48h. In group 3, spheroid configuration was sustained until day 10, though slightly flattened. In group 4, the spheroid configuration was well maintained throughout the culture period. Urea synthesis of the spheroids cultured with collagen gel was significantly higher than in group 1 between days 1 and 3. Albumin synthesis of three experimental groups was also significantly higher than that of group 1. Although three experimental groups showed no difference in urea synthesis, albumin production by spheroids in groups 3 and 4 was better maintained than in group 2, even toward the end of the culture period. It is concluded that mixed liver-cell spheroid culture within collagen gels showed better maintenance of their configuration and function.