Department of Orthopaedic Surgery, The First Hospital of Jilin University, Xinmin Street No. 71, Changchun TX: 130021, PR China; Key Laboratory of Polymer Ecomaterials, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun TX: 130022, PR China.
School of Public Health, Jilin University, Changchun 130021, PR China.
Mater Sci Eng C Mater Biol Appl. 2015 Jan;46:158-65. doi: 10.1016/j.msec.2014.10.014. Epub 2014 Oct 5.
To explore the controlled delivery of protein drugs in micro-environment established by osteoblasts or osteoclasts, the loading/release properties of bovine serum albumin (BSA) depending on pH environment were assessed. The adsorption amounts over mesoporous hydroxyapatite (MHA) or hydroxyapatite (HA) decreased as the pH increased, negatively correlating with zeta-potential values. The adsorption behavior over MHA fits well with the Freundlich and Langmuir models at different pHs. The results suggest that the adsorbed amount of protein on MHA or HA depended on the pH of protein solution. MHA adsorbed BSA at basic pH (MHApH 8.4) exhibited a different release kinetics compared with those in acid and neutral environments (MHApH 4.7 and MHApH 7.4), indicating that the release of protein could be regulated by environmental pH at which MHAs adsorb protein. MHApH 8.4 showed a sustained release for 6h before a gradual release when immersing in acidic environment, which is 2h longer than that in neutral environment. This suggests that MHApH 8.4 showed a more sustained release in acidic environment, which can be established by osteoclasts. The variation of adsorption strength between protein and MHA may be responsible for these behaviors. Our findings may be very useful for the development of MHA applications on both bone repair and protein delivery.
为了探索在成骨细胞或破骨细胞所建立的微环境中对蛋白质类药物的控制释放，评估了牛血清白蛋白（BSA）在不同 pH 值环境下的载入/释放性能。BSA 在介孔羟基磷灰石（MHA）或羟基磷灰石（HA）上的吸附量随 pH 值的升高而降低，与 ζ 电位值呈负相关。在不同 pH 值下，MHA 上的吸附行为均符合弗伦德利希（Freundlich）和朗缪尔（Langmuir）模型。结果表明，MHA 或 HA 上蛋白质的吸附量取决于蛋白质溶液的 pH 值。与在酸性和中性环境（MHApH4.7 和 MHApH7.4）中的释放动力学相比，在碱性 pH 值（MHApH8.4）下吸附的 BSA 具有不同的释放动力学，这表明通过吸附蛋白质的 MHA 的环境 pH 值可以调节蛋白质的释放。当在酸性环境中浸泡时，MHApH8.4 在 6 小时内呈现持续释放，然后逐渐释放，比在中性环境中长 2 小时。这表明，MHApH8.4 在酸性环境中表现出更持续的释放，这种释放可以由破骨细胞建立。蛋白质和 MHA 之间吸附强度的变化可能是导致这些行为的原因。我们的研究结果可能对开发 MHA 在骨修复和蛋白质递送方面的应用非常有用。
