ABSTRACT
Collagen is the most abundant protein in animals, and its polymer, collagen fibrils, regulate cellular proliferation, differentiation, and migration. Low antigenicity, biocompatibility, and biodegradability make collagen fibrils suitable functional scaffolds for tissue engineering. In a previous study, we found that the type I atelocollagen purified from the swim bladder of Bester sturgeon (swim bladder collagen, SBC) showed high fibril-forming ability, producing thicker fibrils faster than porcine collagen. In this study, we report a novel method to coat cell culture wells with highly aligned collagen fibrils using the SBC. Two types of fibrils with different thicknesses were prepared by changing the crosslinking treatment timing. The oriented, thick collagen fibrils induced pre-osteoblastic MC3T3-E1, pre-adipocytic 3T3-L1, pre-myocytic C2C12, and fibroblastic L929 cells to align in the same direction, whereas the oriented, fine fibrils made a cell network with their long pseudopods. Cellular proliferation was inhibited on both fibrils. Furthermore, both fibrils induced the early differentiation of MC3T3-E1 cells without differentiation stimuli. In contrast, the morphology of pre-chondrocytic ATDC5 cells on both fine and thick fibrils extended very short pseudopods and continued to maintain a spherical shape without stretching, suggesting a distinct effect by the fibrils. The newly developed fibril coatings are in the form of a thin film, thereby providing good visibility of the cell structure, including cell-cell and cell-ECM interactions, using a phase contrast microscope. The fibril coatings have high potential as a useful tool for tissue engineering research.