Chen Haifeng, Chen Yunqing, Orr Bradford G, Holl Mark M Banaszak, Majoros Istvan, Clarkson Brian H
School of Dentistry, Department of Physics, Program in Macromolecular Science and Engineering, Center for Biologic Nanotechnology, University of Michigan, Ann Arbor, Michigan 48109-1078, USA.
Langmuir. 2004 May 11;20(10):4168-71. doi: 10.1021/la0303005.
Although it is known that noncollagenous proteins of dental origin bind to the hydroxyapatite crystal surfaces, no measure of their binding strength has been calculated. This experiment used -COOH-capped generation 7 PAMAM dendrimers as nanoprobes of the biological hydroxyapatite nanorod surfaces. Dendrimer distribution was characterized using AFM. The results showed dendrimers to be spaced at intervals along the c-axis of the crystals. From these observations and assuming a fully ionized -COOH dendrimer, a mathematical model of the binding capacity of the crystal surface with the dendrimer was developed. The Monte Carlo method was used to simulate the binding process between the dendrimer and crystal surface, and the binding strength of the -COOH groups to the surface was calculated to be 90 +/- 20 kJ/mol. These results support the CFM studies which have described alternating bands of charge domains on the crystal surface and that the binding strength will be dependent on both the intensity of the charge on the protein and the crystal surface.
虽然已知牙齿来源的非胶原蛋白会与羟基磷灰石晶体表面结合，但尚未计算出它们的结合强度。本实验使用羧基封端的第7代聚酰胺-胺（PAMAM）树枝状大分子作为生物羟基磷灰石纳米棒表面的纳米探针。使用原子力显微镜（AFM）对树枝状大分子的分布进行了表征。结果表明，树枝状大分子沿晶体的c轴间隔排列。基于这些观察结果，并假设羧基树枝状大分子完全电离，建立了晶体表面与树枝状大分子结合能力的数学模型。采用蒙特卡罗方法模拟树枝状大分子与晶体表面之间的结合过程，计算得出羧基与表面的结合强度为90±20 kJ/mol。这些结果支持了临界场模型（CFM）研究，该研究描述了晶体表面电荷域的交替带，并且结合强度将取决于蛋白质和晶体表面上电荷的强度。
