Matsumoto T, Okazaki M, Inoue M, Yamaguchi S, Kusunose T, Toyonaga T, Hamada Y, Takahashi J
Division of Biomaterials Science, Graduate School of Dentistry, Osaka University, 1-8 Yamadaoka, Suita, Osaka 565-0871, Japan.
Biomaterials. 2004 Aug;25(17):3807-12. doi: 10.1016/j.biomaterials.2003.10.081.
This study examines the possibility of using hydroxyapatite (HAp) particles as a controlled release carrier of protein. In order to achieve effective protein release from HAp particles, it is necessary to regulate the conjugated amount of protein on HAp and the resorption of HAp. HAp particles were synthesized at different temperatures (40 degrees C, 60 degrees C, 80 degrees C) in wet condition and the physico-chemical properties of synthesized HAp particles were examined. HAp particles synthesized at low temperatures showed low crystallinity, high solubility and large specific surface area. The useful growth factors for bone regeneration, such as BMP, bFGF and TGF-beta, are basic proteins, so cytochrome c (pI=10.2) was used as a model protein and the adsorptive property of protein on HAp particles was investigated. The protein adsorption on HAp particles changed depending on its specific surface area and the chart of protein adsorption on HAp particles showed a typical Langmuir curve. These findings suggest that the adsorbed amount of protein on HAp particles could be regulated by HAp synthesizing temperature and the concentrations of protein solution. The release kinetics of protein from the HAp particles that adsorbed the protein (HAp-pro) was also evaluated in different pH solutions (pH 4.0 and 7.0). The released protein gradually increased time dependently when HAp-pro were immersed in pH 4.0 solution, but the released protein was significantly smaller when HAp-pro were immersed in pH 7.0 solution. Moreover, the release rate of protein from HAp-pro differed in each HAp that was synthesized at different temperatures, suggesting that the release of protein from HAp-pro depended on HAp resorption. These results suggest that HAp particles synthesized at different temperature are useful as a controlled release carrier of protein.
本研究考察了使用羟基磷灰石（HAp）颗粒作为蛋白质控释载体的可能性。为了实现蛋白质从HAp颗粒中的有效释放，有必要调节蛋白质在HAp上的结合量以及HAp的再吸收。在湿法条件下于不同温度（40℃、60℃、80℃）合成HAp颗粒，并对合成的HAp颗粒的物理化学性质进行了考察。低温合成的HAp颗粒结晶度低、溶解度高且比表面积大。骨再生的有用生长因子，如骨形态发生蛋白（BMP）、碱性成纤维细胞生长因子（bFGF）和转化生长因子-β（TGF-β）都是碱性蛋白质，因此使用细胞色素c（pI = 10.2）作为模型蛋白，研究了蛋白质在HAp颗粒上的吸附特性。蛋白质在HAp颗粒上的吸附因其比表面积而异，蛋白质在HAp颗粒上的吸附图呈现典型的朗缪尔曲线。这些发现表明，HAp颗粒上蛋白质的吸附量可通过HAp合成温度和蛋白质溶液浓度来调节。还在不同pH溶液（pH 4.0和7.0）中评估了吸附蛋白质的HAp颗粒（HAp-pro）中蛋白质的释放动力学。当HAp-pro浸入pH 4.0溶液中时，释放的蛋白质随时间逐渐增加，但当HAp-pro浸入pH 7.0溶液中时，释放的蛋白质明显较少。此外，不同温度合成的每种HAp中，HAp-pro释放蛋白质的速率不同，这表明HAp-pro中蛋白质的释放取决于HAp的再吸收。这些结果表明，不同温度合成的HAp颗粒可作为蛋白质的控释载体。
