Nanocrystalline spherical hydroxyapatite granules for bone repair: in vitro evaluation with osteoblast-like cells and osteoclasts
Nanocrystalline spherical hydroxyapatite granules for bone repair: in vitro evaluation with osteoblast-like cells and osteoclasts
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DOI：
10.1007/s10856-013-4933-2
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发表时间：
2013-07-01
影响因子：
3.7
通讯作者：
Gelinsky, M.
中科院分区：
文献类型：
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作者：
Bernhardt, A.;Dittrich, R.;Gelinsky, M.
常规烧结的羟基磷灰石基骨修复材料由于纳米结晶度的损失而显示出较差的可吸收性。本研究描述了一种制备纳米羟基磷灰石颗粒的方法。该材料是通过含有羟基磷灰石（HA）粉末的藻酸盐溶胶的离子凝胶化制备的。随后在650 A摄氏度下热消除藻酸盐产生未烧结但出乎意料地稳定的羟基磷灰石颗粒。通过将硬脂酸作为有机填料添加到藻酸盐/HA悬浮液中，颗粒在热处理后表现出大孔。第三种类型的材料是通过用二氧化硅颗粒额外涂覆颗粒来实现的。通过与已经确定的粒状磷酸钙材料Cerasorb M-A（R）进行比较，对不同材料的微观结构和比表面积进行了表征。通过骨肉瘤细胞和破骨细胞的体外实验评价材料的细胞相容性和骨再生潜力。成骨样SaOS-2细胞在所有检测材料上增殖，并在培养过程中表现出碱性磷酸酶（ALP）活性的典型增加。RT-PCR检测表明，材料上有ALP、骨连接素、骨桥蛋白、骨钙素和骨唾液蛋白II等骨相关基因的表达。将人单核细胞接种到不同的颗粒上，并通过酒石酸特异性酸性磷酸酶（TRAP）的活性测量来检查破骨细胞生成。培养23天后的基因表达分析显示，破骨细胞相关基因TRAP，玻连蛋白受体和组织蛋白酶K的表达增加，这是在同一水平上的所有检查材料。这些结果表明，纳米晶颗粒材料具有临床意义，特别是用于骨再生。
Conventionally sintered hydroxyapatite-based materials for bone repair show poor resorbability due to the loss of nanocrystallinity. The present study describes a method to establish nanocrystalline hydroxyapatite granules. The material was prepared by ionotropic gelation of an alginate sol containing hydroxyapatite (HA) powder. Subsequent thermal elimination of alginate at 650 A degrees C yielded non-sintered, but unexpectedly stable hydroxyapatite granules. By adding stearic acid as an organic filler to the alginate/HA suspension, the granules exhibited macropores after thermal treatment. A third type of material was achieved by additional coating of the granules with silica particles. Microstructure and specific surface area of the different materials were characterized in comparison to the already established granular calcium phosphate material Cerasorb M-A (R). Cytocompatibility and potential for bone regeneration of the materials was evaluated by in vitro examinations with osteosarcoma cells and osteoclasts. Osteoblast-like SaOS-2 cells proliferated on all examined materials and showed the typical increase of alkaline phosphatase (ALP) activity during cultivation. Expression of bone-related genes coding for ALP, osteonectin, osteopontin, osteocalcin and bone sialoprotein II on the materials was proven by RT-PCR. Human monocytes were seeded onto the different granules and osteoclastogenesis was examined by activity measurement of tartrate-specific acid phosphatase (TRAP). Gene expression analysis after 23 days of cultivation revealed an increased expression of osteoclast-related genes TRAP, vitronectin receptor and cathepsin K, which was on the same level for all examined materials. These results indicate, that the nanocrystalline granular materials are of clinical interest, especially for bone regeneration.