Bessho Masahiko, Furuta Masakazu, Kojima Takao, Okuda Shuichi, Hara Masayuki
Research Institute for Advanced Science and Technology, Osaka Prefecture University, 1-2 Gakuen-cho, Sakai City, Osaka 599-8531, Japan.
J Biomater Sci Polym Ed. 2005;16(6):715-24. doi: 10.1163/1568562053992478.
Gelatin hydrogels cross-linked by y-ray irradiation using 60Co as gamma-ray source were prepared. As a model of controlled release of low-molecular-weight compounds, absorption and release of methylene blue, a water-soluble cationic dye, was investigated. Irradiated gelatin hydrogels did not redissolve at temperatures over 40 degrees C, while unirradiated gels were thermoplastic and reversibly changed the stage between gel and sol. Measurement of both the wet weight after swelling in distilled water and dry weight after freeze-drying showed that the higher-dose irradiation gave stiffer and more compact gels with the lower specific water content, irrespective of the absorbed dose rate. The time-course of absorption and release of methylene blue in aqueous solution was measured. Since absorption of dye into gelatin gels was much affected by liquid phase pH, amount of absorption was higher in pH above an IEP of gelatins. Moreover, the absorption and release of methylene blue with Type-B gelatin were higher than with Type-A gelatin, respectively. Therefore, absorption and release of the dye depend on the electrostatic interaction between the dye molecule and gelatin.
制备了以60Co作为γ射线源通过γ射线辐照交联的明胶水凝胶。作为低分子量化合物控释的模型，研究了水溶性阳离子染料亚甲基蓝的吸收和释放。辐照后的明胶水凝胶在温度超过40℃时不会再溶解，而未辐照的凝胶是热塑性的，并且在凝胶和溶胶之间可逆地变化状态。对在蒸馏水中溶胀后的湿重和冷冻干燥后的干重进行测量表明，无论吸收剂量率如何，较高剂量的辐照都会产生更硬且更致密的凝胶，其比含水量更低。测量了亚甲基蓝在水溶液中的吸收和释放的时间进程。由于染料进入明胶水凝胶的吸收受液相pH值的影响很大，在高于明胶等电点的pH值下吸收量更高。此外，B型明胶对亚甲基蓝的吸收和释放分别高于A型明胶。因此，染料的吸收和释放取决于染料分子与明胶之间的静电相互作用。
