Dalas E, Malkaj P, Vasileiou Z, Kanellopoulou D G
Department of Chemistry, University of Patras, Patras 26504, Greece.
J Mater Sci Mater Med. 2008 Jan;19(1):277-82. doi: 10.1007/s10856-006-0050-9. Epub 2007 Jun 28.
Crystallization kinetics of hydroxyapatite, HAP, in the presence of Leucine, a natural amino acid with hydrophobic side groups, were investigated at conditions of sustained supersaturation, 37 degrees C, pH 7.40, ionic strength 0.15 M. In the presence of Leucine, the crystal growth rates of HAP decreased markedly. Tauhis action is due to adsorption and subsequent blocking of the active growth sites onto the surface of the HAP crystals. The kinetic results revealed that a Langmuir-type adsorption isotherm is followed and an affinity constants of k(aff )=20.26 x 10(2) L/mol for HAP crystal surface were calculated. The apparent order of the crystal growth reaction was found to be equal to two, suggesting a surface diffusion controlled mechanism.
在37℃、pH 7.40、离子强度0.15 M的持续过饱和条件下，研究了在具有疏水侧基的天然氨基酸亮氨酸存在下羟基磷灰石（HAP）的结晶动力学。在亮氨酸存在下，HAP的晶体生长速率显著降低。这种作用是由于亮氨酸吸附并随后阻断了HAP晶体表面的活性生长位点。动力学结果表明，遵循朗缪尔型吸附等温线，并计算出HAP晶体表面的亲和常数k(aff ) = 20.26×10² L/mol。发现晶体生长反应的表观级数等于二级，表明是表面扩散控制机制。
