Radiation stability and modification of gelatin for biological and medical applications

• Mw of solid gelatin decreased by approximately7–10% with sterilization doses of 5–25 kGy.
• Hydrolysis rate of gelatin at 37 °C was decreased after radiation decomposition.
• Gelatin was radiation-crosslinked (RX) when irradiated in water solution.
• Simultaneous fabrication and sterilization of RX-gelatin hydrogel were performed.
• RX-gelatin hydrogel was stable for 7 days in water at 37 °C.

Gelatin is used in various biological and medical fields, including drug delivery systems and tissue engineering. In the context of these applications, radiation sterilization of gelatin was evaluated in terms of radiation stability. The molecular weight of gelatin powder irradiated by electron beams (EB) was analyzed using gel permeation chromatography (GPC). We found that irradiation decomposed the gelatin and that the weight-averaged molar mass (Mw) decreased by approximately 7–10% with sterilization doses in the range of 5–25 kGy. Also, we found that the hydrolysis rate in body and cell culture environments (37 °C water) was affected by irradiation. Although gelatin powder underwent chain scission when irradiated, crosslinking was predominantly induced when the gelatin was irradiated in water solution. Radiation-crosslinked (RX) gelatin hydrogel was fabricated without using any crosslinkers. In this case, fabrication and radiation sterilization were performed simultaneously. Using gel fraction and GPC analysis of the eluted sol, it was determined that the RX-gelatin hydrogel was stable for 7 days in water at 37 °C. These results provide important data for evaluating the feasibility of biological and medical applications of gelatin and RX-gelatin hydrogel.