W. M. Keck Biomedical Materials Research Laboratory, School of Mechanical and Materials Engineering, Washington State University, Pullman, WA 99164-2920, USA.
Mater Sci Eng C Mater Biol Appl. 2013 Oct;33(7):3576-82. doi: 10.1016/j.msec.2013.04.001. Epub 2013 Apr 10.
β-Tricalcium phosphate (β-TCP) with three different particle size ranges was used to study the effects of particle size and surface area on protein adsorption and release. Polycaprolactone (PCL) coating was applied on the particle systems to investigate its effect on particulate system properties from both structural and application aspects. The maximum loading of 27 mg/g was achieved for 100 nm particles. Bovine serum albumin (BSA) loading amount was controlled by varying the BSA loading solution concentration, as well as the sample powder's surface area. Increasing the surface area of the delivery powder significantly increased loading and release yield. Unlike the samples with low surface area, the lowest particle size samples showed sigmoidal release profile. This indicated that release was governed by different mechanisms for particles with different sizes. While the majority of samples showed no more than 50% release, the 550 nm particles demonstrated 100% release. PCL coating showed no significant ability to attenuate burst release in PBS. However, it led to a steadier release profile as compared to the bare TCP particles. FTIR analysis also proved that the secondary structure of BSA did not change significantly during the adsorption; however, minor denaturation was found during the release. The same results were found when PCL coating was applied on the TCP particles. We envision potential use of TCP and TCP+PCL systems in bone growth factor or orthopedic drug delivery applications in future bone tissue engineering application.
β-磷酸三钙（β-TCP）具有三种不同的粒径范围，用于研究粒径和比表面积对蛋白质吸附和释放的影响。聚己内酯（PCL）涂层被应用于颗粒体系，从结构和应用两个方面研究其对颗粒体系性能的影响。对于 100nm 粒径的颗粒，达到了 27mg/g 的最大载药量。通过改变 BSA 加载溶液浓度以及样品粉末的比表面积来控制牛血清白蛋白（BSA）的载药量。增加给药粉末的比表面积显著提高了载药量和释放产率。与低比表面积的样品不同，最小粒径的样品表现出 S 型释放曲线。这表明不同粒径的颗粒释放机制不同。虽然大多数样品的释放量不超过 50%，但 550nm 粒径的样品释放量达到 100%。PCL 涂层在 PBS 中对突释释放没有明显的抑制作用。然而，与裸 TCP 颗粒相比，它导致了更稳定的释放曲线。傅里叶变换红外（FTIR）分析也证明了 BSA 的二级结构在吸附过程中没有发生显著变化；然而，在释放过程中发现了轻微的变性。当 PCL 涂层应用于 TCP 颗粒时，也得到了相同的结果。我们设想在未来的骨组织工程应用中，TCP 和 TCP+PCL 系统有可能用于骨生长因子或骨科药物输送应用。
