Biocompatibility control of recombinant collagen by ion beam modification

Collagen, which is widely used as a biomaterial because of its excellent tissue compatibility, is generally extracted from animal tissues. The animal-derived biomaterials have the potential for viral or infectious agent contamination risks and allergic reaction problems. Therefore, this study focused on a recombinant human collagen which was pure and homogeneous, compared to the collagen derived from animals. Recombinant human type I collagen was modified by using an ion beam to control the biocompatibility for the substrates of medical devices. He+ ion beam irradiation of the recombinant collagen was performed at an energy of 150 keV with fluences of 1 × 1013, 1 × 1014 and 1 × 1015 ions/cm2. To investigate anti-thrombogenicity, Ca2+-replenished platelet-rich plasma (PRP) was placed in contact with the surfaces for 5 min. Platelet response was significantly inhibited at a fluence of 1 × 1014 ions/cm2, although the surfaces of the non-modification and other fluences promoted this response. Endothelial cells were cultured on the surfaces for 4 days to evaluate the cellular response. The cell-adhesive property of the recombinant collagen still remained at the fluences of 1 × 1014 ions/cm2 or less; however, the surface modified with a fluence of 1 × 1015 ions/cm2 dramatically inhibited the cell adhesion. These results suggest that platelet and cell adhesion onto the recombinant collagen surface can be individually controlled by the fluence of 150 keV He+ ion beam modification. It is concluded that the recombinant collagen surface modified with a fluence of 1 × 1014 ions/cm2 not only retains cell-adhesive property but also possesses anti-thrombogenicity.