Du Rui Lin, Chang Jiang
Graduate School of Chinese Academy of Sciences, Shanghai 200050, China.
Biomed Mater Eng. 2006;16(4):229-36.
To evaluate the influence of Zn on the formation of hydroxyapatite (HA), zinc-containing glass 58S4Z was prepared by substitution of CaO with 4 wt% ZnO in 58S bioactive glass, and Zn-containing simulated body fluid (ZnSBF) was prepared as soaking fluid. During the soaking, all samples could induce the deposition of HA, but 58S4Z in SBF and 58S in ZnSBF showed lower formation rate of HA than 58S in SBF, which suggests that both the Zn in glass and the Zn2+ in soaking fluid retarded the deposition of HA. The ICP and EDS analysis results indicated that the main factor was the preferential reaction of Zn2+ with PO4(3-), which resulted in a decrease of the PO4(3-) concentration in soaking fluid and the nucleation of HA. Besides the inhibitory effect of Zn2+ in the soaking fluid, Zn in 58S4Z glass caused a lower release rate of Ca2+ in the initial soaking periods because of the lower CaO content as compared with 58S, and resulted in a lower nucleation rate of HA. The results suggested that small amount of Zn in bioactive glass retarded the nucleation of HA, but with the exhaustion of Zn2+ by PO4(3-), it did not affect the long-term deposition of HA in SBF.
为了评估锌对羟基磷灰石（HA）形成的影响，通过在58S生物活性玻璃中用4 wt%的ZnO替代CaO制备了含锌玻璃58S4Z，并制备了含锌模拟体液（ZnSBF）作为浸泡液。在浸泡过程中，所有样品都能诱导HA的沉积，但SBF中的58S4Z和ZnSBF中的58S的HA形成速率低于SBF中的58S，这表明玻璃中的锌和浸泡液中的Zn2+都阻碍了HA的沉积。ICP和EDS分析结果表明，主要因素是Zn2+与PO4(3-)的优先反应，这导致浸泡液中PO4(3-)浓度降低以及HA的成核。除了浸泡液中Zn2+的抑制作用外，与58S相比，58S4Z玻璃中的锌由于CaO含量较低，在初始浸泡阶段导致Ca2+的释放速率较低，从而导致HA的成核速率较低。结果表明，生物活性玻璃中的少量锌阻碍了HA的成核，但随着PO4(3-)耗尽Zn2+，它并不影响HA在SBF中的长期沉积。
