Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117542.
J Phys Chem B. 2009 Dec 24;113(51):16393-9. doi: 10.1021/jp905846p.
Fluoride exerts a substantial impact on the biominearlization of hydroxyapatite (HAP). In this study, the effect of fluoride on the nucleation kinetics of HAP was examined quantitatively in a simulated body fluid. It was found for the first time that fluoride promotes the nucleation of HAP. Furthermore, both the concentration of fluoride and the supersaturation of HAP play a key role in the formation of an ordered assembly of rod-like HAP crystallites. At relatively low concentrations of fluoride, an ordered assembly of rod-like crystallites similar to the structure of enamel could be obtained in the simulated body fluid, which could be explained by the self-epitaxial nucleation-mediated assembly. At high concentrations, fluoride may lead to the deterioration of the ordered assembled structure of HAP crystallites. That result is caused by the fast nucleation and growth of HAP crystallites when the supply of nucleation seeds is limited, resulting in the formation of spherulites. Our results illustrate how and why fluoride influences the self-assembled structures of HAP crystallites at low and high concentrations of F(-). Thus, they will substantially advance our understanding on the impact of fluoride ions on the mineralization of HAP and consequently on the dental and bone fluorosis.
氟化物对羟基磷灰石（HAP）的生物矿化有很大的影响。在这项研究中，我们在模拟体液中定量研究了氟化物对 HAP 成核动力学的影响。我们首次发现氟化物能促进 HAP 的成核。此外，氟化物的浓度和 HAP 的过饱和度在形成有序的棒状 HAP 晶须组装体中起着关键作用。在相对较低的氟化物浓度下，可以在模拟体液中获得类似于牙釉质结构的有序棒状晶须组装体，这可以用自外延成核介导的组装来解释。在高浓度下，氟化物可能导致 HAP 晶须组装体有序结构的恶化。这是由于在成核种子供应有限的情况下，HAP 晶须的快速成核和生长导致形成球晶。我们的结果说明了氟化物如何以及为何在低浓度和高浓度 F（-）下影响 HAP 晶须的自组装结构。因此，这些结果将大大提高我们对氟离子对 HAP 矿化的影响以及对牙齿和骨骼氟中毒的认识。
