Application of radiation crosslinking technique to development of gelatin scaffold for tissue engineering

Abstract

The potential of a radiation crosslinking technique for developing gelatin scaffolds for tissue engineering was evaluated by comparing it with a chemical crosslinking method. Radiation-crosslinked gelatin exhibited higher visible light transmittance as compared to chemically crosslinked gelatin. The radiation crosslinking efficiency of the gelatin was estimated to be 91%; it was affected by hydroxyl (OH) radicals formed by γ-radiolysis of the aqueous gelatin solution under nitrous oxide or nitrogen-saturated conditions. The proportions of phenylalanine, tyrosine, and histidine in the gelatin decreased significantly with increasing absorbed dose. At the same time, the amounts of 12 other amino acids remained almost unchanged after γ-ray irradiation, and these amino acids did not participate in the crosslinking reactions. The contents of tyrosine, phenylalanine, and histidine in gelatin were the most important factors for radiation crosslinking. Cell adhesion of the radiation-crosslinked gelatin would be maintained before and after γ-ray irradiation because there was no decrease in the proportion of the cell adhesion active sequence (arginine-glycine-aspartic acid, RGD motif). The yield for dityrosine formation was estimated to be 0.030 µmol l−1 Gy−1, and this is considered to be the point at which crosslinking occurred in the radiation-crosslinked gelatin. As the crosslinked gelatin and degradation products have no absorption bands in the visible region, the radiation crosslinking technique, unlike chemically crosslinking techniques, can modify the gelatin while maintaining high transparency.