Requirement for both micron- and submicron scale structure for synergistic responses of osteoblasts to substrate surface energy and topography
Requirement for both micron- and submicron scale structure for synergistic responses of osteoblasts to substrate surface energy and topography
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DOI：
10.1016/j.biomaterials.2007.02.024
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发表时间：
2007-06-01
期刊：
影响因子：
14
通讯作者：
Boyan, B. D.
中科院分区：
文献类型：
--
作者：
Zhao, G.;Raines, A. L.;Boyan, B. D.
目的：表面粗糙度和表面自由能是调节细胞对生物材料反应的两个重要因素。先前的研究证实，具有微米级和亚微米级形貌的钛(Ti)衬底可以促进成骨细胞分化和成骨局部因子的产生，并且对于通过限制碳氢化合物污染的加工保持其高表面能量的微粗糙钛表面，存在协同反应。本研究验证了成骨细胞对这些修饰表面的协同反应取决于表面微结构和表面能的假说。方法：制备了三种不同的表面结构：表面光滑的预处理层(PT)表面，表面Ra为0.2微米，酸蚀表面(A)，亚微米粗糙度R-a为0.83微米；与常规低表面能A和SLA表面进行了比较，结果表明，改性酸蚀(MODA)和改性喷砂/酸蚀(ModSLA)钛表面污染小，表面羟基/水化，保持了较高的表面能。在此基础上培养人成骨样MG63细胞，分析细胞形态、生长、分化(碱性磷酸酶、骨钙素)和局部因子产生(转化生长因子β1、前列腺素E(2)、骨保护素(OPG))的反应(每个变量N=6)。结果：除OPG略有增加外，光滑的PT和A表面之间无显著差异。与A表面相比，MG63细胞在MODA上多产生30%的骨钙素，在SLA上多产生70%的骨钙素。然而，在modSLA上的生长增加了超过250%的骨钙素，这超过了表面能和地形的独立影响的总和。当检测条件介质中潜伏的转化生长因子-β1、前列腺素E_2和骨钙素的水平时，也发现了类似的效应。结论：结果表明高表面能与钛衬底的表面形貌之间存在协同效应，说明微米级和亚微米级的结构特征都是必要的。(C)2007爱思唯尔有限公司。保留所有权利。
Objective: Surface roughness and surface free energy are two important factors that regulate cell responses to biomaterials. Previous studies established that titanium (Ti) substrates with micron-scale and submicron scale topographies promote osteoblast differentiation and osteogenic local factor production and that there is a synergistic response to micro-rough Ti surfaces that have retained their high surface energy via processing that limits hydrocarbon contamination. This study tested the hypothesis that the synergistic response of osteoblasts to these modified surfaces depends on both surface micro-structure and surface energy.Methods: Ti disks were manufactured to present three different surface structures: smooth pretreatment (PT) surfaces with Ra Of 0.2 mu m; acid-etched surfaces (A) with a submicron roughness R-a of 0.83 mu m; and sandblasted/acid-etched surfaces (SLA) with R-a of 3-4 mu m. Modified acid-etched (modA) and modified sandblasted/acid-etched (modSLA) Ti substrates, which have low contamination and present a hydroxylated/hydrated surface layer to retain high surface energy, were compared with regular low surface energy A and SLA surfaces. Human osteoblast-like MG63 cells were cultured on these substrates and their responses, including cell shape, growth, differentiation (alkaline phosphatase, osteocalcin), and local factor production (TGF-beta 1, PGE(2), osteoprotegerin (OPG)) were analyzed (N = 6 per variable). Data were normalized to cell number.Results: There were no significant differences between smooth PT and A surfaces except for a small increase in OPG. Compared to A surfaces, MG63 cells produced 30% more osteocalcin on modA, and 70% more on SLA. However, growth on modSLA increased osteocalcin by more than 250%, which exceeded the sum of independent effects of surface energy and topography. Similar effects were noted when levels of latent TGF-beta 1, PGE2 and OPG were measured in the conditioned media.Conclusions: The results demonstrate a synergistic effect between high surface energy and topography of Ti substrates and show that both micron-scale and submicron scale structural features are necessary. (C) 2007 Elsevier Ltd. All rights reserved.