Pernodet Nadine, Rafailovich Miriam, Sokolov Jonathan, Xu D, Yang Nan-Loh, McLeod Kenneth
Departments of Orthopaedics and Materials Science and Engineering, State University of New York, Stony Brook, New York 11794-5281, USA.
J Biomed Mater Res A. 2003 Mar 15;64(4):684-92. doi: 10.1002/jbm.a.10394.
Extracellular matrix (ECM) protein adsorption and organization serves as a critical first step in the development and organization of tissues. Advances in tissue engineering, therefore, will depend on the ability to control the rate and pattern of ECM formation. Fibronectin is a prominent component of the ECM, which undergoes fibrillogenesis in the presence of cells. Using sulfonated polysyrene surfaces, we showed that fibronectin undergoes a transition from monolayer to multilayer adsorption at calculated surface charge densities above 0.03 Coulombs (C)/m(2). At charge densities above approximately 0.08 C/m(2), distinct fibronectin fibrillar networks are observed to form with a fibril morphology similar to those observed to form in situ on cell surfaces. This self-organization process is time dependent, with the fibrils achieving dimensions of 30-40 microm in length and 1 microm in height after 72 h of incubation. We suggest that the polarization of charge domains on the polyampholytic fibronectin molecules near high charge density surfaces is sufficient to initiate the multilayer adsorption and the organization of these fibrillar structures. These results suggest that the nonlinear dependence of adsorption on surface charge density may play an important role in the self-organization of many matrix components.
细胞外基质（ECM）蛋白的吸附与组织化是组织发育和形成过程中的关键第一步。因此，组织工程的进展将取决于控制ECM形成速率和模式的能力。纤连蛋白是ECM的重要组成部分，在细胞存在的情况下会发生纤维形成。利用磺化聚苯乙烯表面，我们发现，当计算出的表面电荷密度高于0.03库仑（C）/平方米时，纤连蛋白会从单层吸附转变为多层吸附。在电荷密度高于约0.08 C/平方米时，会观察到形成了独特的纤连蛋白纤维网络，其纤维形态与在细胞表面原位观察到的相似。这种自组织过程是时间依赖性的，孵育72小时后，纤维长度达到30 - 40微米，高度达到1微米。我们认为，在高电荷密度表面附近，两性离子纤连蛋白分子上的电荷域极化足以引发多层吸附和这些纤维结构的组织化。这些结果表明，吸附对表面电荷密度的非线性依赖性可能在许多基质成分的自组织中起重要作用。
