Department of Orthodontics, Nanjing Stomatological Hospital, Medical School of Nanjing University, 210008 Nanjing, China; Department of Oral Implantology and Prosthetic Dentistry, Academic Centre of Dentistry Amsterdam (ACTA), VU University and University of Amsterdam, 1081LA Amsterdam, the Netherlands.
Departments of Osteoporosis and Orthopaedic Surgery, Inselspital (University Hospital), Bern, 3010 Bern, Switzerland.
Mater Sci Eng C Mater Biol Appl. 2019 Mar;96:329-336. doi: 10.1016/j.msec.2018.11.017. Epub 2018 Nov 14.
(1) To determine whether the biocompatibility of coralline hydroxyapatite (CHA) granules could be improved by using an octacalcium phosphate (OCP) coating layer, and/or functionalized with bone morphogenetic protein 2 (BMP-2), and (2) to investigate if BMP-2 incorporated into this coating is able to enhance its osteoinductive efficiency, in comparison to its surface-adsorbed delivery mode.
CHA granules (0.25 g per sample) bearing a coating-incorporated depot of BMP-2 (20 μg/sample) together with the controls (CHA bearing an adsorbed depot of BMP-2; CHA granules with an OCP coating without BMP-2; pure CHA granules) were implanted subcutaneously in rats (n = 6 animals per group). Five weeks later, the implants were retrieved for histomorphometric analysis to quantify the volume of newly generated bone, bone marrow, fibrous tissue and foreign body giant cells (FBGCs). The osteoinductive efficiency of BMP-2 and the rates of CHA degradation were also determined.
The group with an OCP coating-incorporated depot of BMP-2 showed the highest volume and quality or bone, and the highest osteoinductive efficacy. OCP coating was able to reduce inflammatory responses (improve biocompatibility), and also simple adsorption of BMP-2 to CHA achieved this.
The biocompatibility of CHA granules (reduction of inflammation) was significantly improved by coating with a layer of OCP. Pure surface adsorption of BMP-2 to CHA also reduced inflammation. Incorporation of BMP-2 into the OCP coatings was associated with the highest volume and quality of bone, and the highest biocompatibility degree of the CHA granules.
Higher osteoinductivity and improved biocompatibility of CHA can be obtained when a layer of BMP-2 functionalized OCP is deposited on the surfaces of CHA granules.
（1）确定八钙磷酸盐（OCP）涂层和/或骨形态发生蛋白 2（BMP-2）功能化是否可以提高珊瑚羟基磷灰石（CHA）颗粒的生物相容性，（2）研究与表面吸附递送方式相比，掺入这种涂层的 BMP-2 是否能够增强其成骨诱导效率。
将含有 BMP-2 包埋库的 CHA 颗粒（每个样品 0.25g，共 20μg/sample）以及对照物（含有吸附 BMP-2 的库的 CHA；无 BMP-2 的 OCP 涂层 CHA 颗粒；纯 CHA 颗粒）植入大鼠皮下（每组 6 只动物）。5 周后，取出植入物进行组织形态计量学分析，以定量测量新生成的骨、骨髓、纤维组织和异物巨细胞（FBGC）的体积。还确定了 BMP-2 的成骨诱导效率和 CHA 降解率。
具有 OCP 涂层包埋库的 BMP-2 组显示出最高的骨体积和质量，以及最高的成骨诱导效率。OCP 涂层能够减少炎症反应（提高生物相容性），并且 BMP-2 简单地吸附到 CHA 上也能实现这一点。
用 OCP 层涂覆 CHA 颗粒可显著提高其生物相容性（减少炎症）。BMP-2 纯表面吸附到 CHA 上也可减轻炎症。将 BMP-2 掺入 OCP 涂层中与骨的最高体积和质量以及 CHA 颗粒的最高生物相容性程度相关。
当将功能化的 BMP-2 OCP 层沉积在 CHA 颗粒表面时，可以获得更高的成骨诱导性和改善 CHA 的生物相容性。
