In situ observation of fluoride-ion-induced hydroxyapatite-collagen detachment on bone fracture surfaces by atomic force microscopy
In situ observation of fluoride-ion-induced hydroxyapatite-collagen detachment on bone fracture surfaces by atomic force microscopy
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DOI：
10.1088/0957-4484/18/13/135102
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发表时间：
2007-04-04
期刊：
影响因子：
3.5
通讯作者：
Hansma, P. K.
中科院分区：
文献类型：
--
作者：
Kindt, J. H.;Thurner, P. J.;Hansma, P. K.
新鲜断裂的牛和人骨表面的地形确定通过使用原子力显微镜（AFM）。从这两种样品的断裂表面表现出复杂的景观形成的羟基磷灰石矿物血小板的横向尺寸范围从类似于90 nm × 60 nm到类似于20 nm × 20 nm。新的AFM技术被用来研究这些断裂面在各种化学处理。显着的地形变化后，观察到暴露于乙二胺四乙酸（EDTA）或高浓度氟化钠（氟化钠）的水溶液。两种处理均导致羟基磷灰石矿物血小板在几秒的时间尺度上明显损失。胶原纤维位于下面的覆盖矿物血小板清楚地暴露，并可以解决与高空间分辨率在所获得的AFM图像。时间依赖性的质量损失实验表明，所施加的代理（氟化钠或EDTA）有非常不同的结果的影响。尽管这两种处理在AFM检查后表现出几乎相同的结果，但用EDTA处理的大块骨样品在72小时后表现出类似于70%的质量损失，而对于NaF处理的样品，质量损失仅为类似于10%的量级。这些结果支持从先前的机械测试实验中获得的那些结果，表明表面氟磷灰石的增强形成显著地削弱了蛋白质-羟基磷灰石界面。此外，我们发现用氟化钠水溶液处理可有效地从骨粉中提取非胶原蛋白。
The topography of freshly fractured bovine and human bone surfaces was determined by the use of atomic force microscopy (AFM). Fracture surfaces from both kinds of samples exhibited complex landscapes formed by hydroxyapatite mineral platelets with lateral dimensions ranging from similar to 90 nm x 60 nm to similar to 20 nm x 20 nm. Novel AFM techniques were used to study these fracture surfaces during various chemical treatments. Significant topographical changes were observed following exposure to aqueous solutions of ethylenediaminetetraacetic acid ( EDTA) or highly concentrated sodium fluoride (NaF). Both treatments resulted in the apparent loss of the hydroxyapatite mineral platelets on a timescale of a few seconds. Collagen fibrils situated beneath the overlying mineral platelets were clearly exposed and could be resolved with high spatial resolution in the acquired AFM images. Time-dependent mass loss experiments revealed that the applied agents ( NaF or EDTA) had very different resulting effects. Despite the fact that the two treatments exhibited nearly identical results following examination by AFM, bulk bone samples treated with EDTA exhibited a similar to 70% mass loss after 72 h, whereas for the NaF-treated samples, the mass loss was only of the order of similar to 10%. These results support those obtained from previous mechanical testing experiments, suggesting that enhanced formation of superficial fluoroapatite dramatically weakens the protein-hydroxyapatite interfaces. Additionally, we discovered that treatment with aqueous solutions of NaF resulted in the effective extraction of noncollagenous proteins from bone powder.