Strengthening mechanisms of bone bonding to crystalline hydroxyapatite in vivo
Strengthening mechanisms of bone bonding to crystalline hydroxyapatite in vivo
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DOI：
10.1016/j.biomaterials.2003.11.017
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发表时间：
2004-08-01
期刊：
影响因子：
14
通讯作者：
Luk, KDK
中科院分区：
文献类型：
--
作者：
Chen, QZ;Wong, CT;Luk, KDK
采用高分辨透射电镜（HRTEM）和能谱分析（EDX）研究了结晶羟基磷灰石（HA）骨结合的形成和强化机制。结果表明：（i）在溶解前，在晶体HA颗粒表面形成了一层与植入HA具有相同化学性质的无定形HA;（ii）在3个月时，在成熟骨和HA植入物之间形成了由纳米晶和无定形磷灰石组成的骨样组织结合区; 6个月时，成熟骨与HA颗粒直接接触，胶原纤维垂直插入植入HA晶体的表层。结果（i）和（ii）表明以下溶解沉淀过程。(i)结晶HA转变成无定形HA;（ii）无定形HA溶解到周围溶液中，导致过饱和;和（iii）在胶原纤维存在下，纳米晶体从过饱和溶液中沉淀。初步分析表明：（1）结晶HA向无定形HA的转变可能是结晶HA骨结合的控制步骤;（二）生物交错胶原纤维与HA的结合（或结合）和磷灰石层的化学结合都是加强和韧化骨结合所必需的，不仅对于6个月时骨和HA之间的结合，而且对于3个月时的结合区也是如此，否则由于多晶陶瓷的固有脆性，该结合区将非常脆弱;以及（iii）垂直交错是胶原纤维将其独特的柔性和强度组合赋予它们所键合的界面的有效方式。(C)2003 Elsevier Ltd.保留所有权利。
The formation and strengthening mechanisms of bone bonding of crystalline hydroxyapatite (HA) has been investigated using high-resolution transmission electron microscope (HRTEM) and energy-dispersive X-ray (EDX) analysis. A series of results were obtained: (i) a layer of amorphous HA, which has almost the same chemistry as the implanted HA, was formed on the surface of crystalline HA particles prior to dissolution; (ii) at 3 months a bone-like tissue formed a bonding zone between mature bone and the HA implant, composed of nanocrystalline and amorphous apatite; and (iii) at 6 months, mature bone was in direct contact with HA particles, and collagen fibres were perpendicularly inserted into the surface layer of implanted HA crystals. Findings (i) and (ii) indicated the following dissolution precipitation process. (i) The crystalline HA transforms into amorphous HA; (ii) the amorphous HA dissolves into the surrounding solution, resulting in over- saturation; and (iii) the nanocrystallites are precipitated from the over-saturated solution in the presence of collagen fibres. A preliminary analysis indicated several conclusions: (i) the transition from crystalline to amorphous HA might be the controlling step in the bone bonding of crystalline HA; (ii) biological interdigitation (or incorporation) of collagen fibres with HA and chemical bonding of a apatite layer were both necessary to strengthen and toughen a bone bond, not only for the bonding between bone and HA at 6 months, but also for the bonding zone at 3 months, which would otherwise be very fragile due to the inherited brittleness of polycrystalline ceramics; and (iii) perpendicular interdigitation is an effective way for collagen fibres to impart their unique combination of flexibility and strength to the interface which they are keying. (C) 2003 Elsevier Ltd. All rights reserved.