Department of Physics and Astronomy, Washington State University, Pullman, Washington 99164, USA.
J Biomed Mater Res B Appl Biomater. 2012 Oct;100(7):1836-45. doi: 10.1002/jbm.b.32751. Epub 2012 Jul 23.
This study investigates the use of hydroxyapatite (HAp) doped with hexavalent tungsten to improve its interaction with bone cells and to influence the polarizing capacity of HAp. Increases in dopant concentration increased the β-TCP phases and decreased the HAp phases in sintered samples. Results of thermally stimulated depolarization current measurements suggested that doped HAp had stored fewer charge compared with pure HAp. However, the decrease in stored charge was related to fraction of HAp or β-TCP phases present in sintered samples. Activation energy of dipole relaxation and stored charge was used to examine the mechanism of polarization. The charge stored in doped samples due to polarization was attributed to the migration of H(+) ions in HAp phases and O(2-) or Ca(2+) ions in β-TCP phases. Hindrance of ion migration due to the presence of different phases appeared to lower charge storage ability in doped samples. In vitro study revealed an increase in bioactivity of doped HAp when compared with pure HAp. Polarization further improved the bioactivity of doped HAp. Results of our study provide evidence for the use of higher valent cations to improve biological performance of HAp ceramics.
本研究探讨了掺杂六价钨的羟基磷灰石（HAp）的应用，以提高其与骨细胞的相互作用，并影响 HAp 的极化能力。掺杂浓度的增加增加了烧结样品中的 β-TCP 相，减少了 HAp 相。热刺激去极化电流测量的结果表明，掺杂 HAp 与纯 HAp 相比存储的电荷量更少。然而，存储电荷的减少与烧结样品中存在的 HAp 或 β-TCP 相的分数有关。偶极子弛豫和存储电荷的激活能用于研究极化机制。掺杂样品中由于极化而存储的电荷归因于 HAp 相中 H(+)离子和 β-TCP 相中 O(2-)或 Ca(2+)离子的迁移。由于存在不同的相，离子迁移的阻碍似乎降低了掺杂样品的电荷存储能力。体外研究表明，与纯 HAp 相比，掺杂 HAp 的生物活性增加。极化进一步提高了掺杂 HAp 的生物活性。我们的研究结果为使用高化合价阳离子来提高 HAp 陶瓷的生物学性能提供了证据。
