Cell growth on immobilized cell growth factor. 9. Covalent immobilization of insulin, transferrin, and collagen to enhance growth of bovine endothelial cells.

Bovine endothelial cells were cultivated on the surface of polyurethane membranes or tubes immobilized with insulin, transferrin, and/or collagen, and growth was measured. For the purpose of immobilization, amino groups were introduced on the membranes or tubes by glow-discharge treatment in the presence of ammonia gas. The proteins were coupled to the amino groups on the surfaces by using dimethyl suberimidate (DMS) or water-soluble carbodiimide (WSC). Growth of bovine endothelial cells was higher on immobilized insulin or transferrin using DMS than that using WSC. The cell growth was higher on immobilized insulin or transferrin than on free insulin or transferrin, respectively. Though immobilized collagen did not affect the cell growth, coimmobilization with insulin or transferrin brought about greater acceleration of cell growth. In addition, the immobilized collagen was indispensible to maintain the endothelial cells on the material surface for a long time. The endothelial cells grown in the polyurethane tubes, on which insulin and collagen are coimmobilized, kept a normal cobblestone-like appearance and maintained the ability to secrete prostacyclin for 9 months.