Molecular Adhesion between Cartilage Extracellular Matrix Macromolecules

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• 作者：Fredrick P. Rojas ; Michael A. Batista ; C. Alexander Lindburg ; Delphine Dean ; Alan J. Grodzinsky ; Christine Ortiz ; Lin Han
• 刊名：Biomacromolecules
• 出版年：2014
• 出版时间：March 10, 2014
• 年：2014
• 卷：15
• 期：3
• 页码：772-780
• 全文大小：559K
• 年卷期：v.15,no.3(March 10, 2014)
• ISSN：1526-4602

文摘

In this study, we investigated the molecular adhesion between the major constituents of cartilage extracellular matrix, namely, the highly negatively charged proteoglycan aggrecan and the type II/IX/XI fibrillar collagen network, in simulated physiological conditions. Colloidal force spectroscopy was applied to measure the maximum adhesion force and total adhesion energy between aggrecan end-attached spherical tips (end radius R 鈮?2.5 渭m) and trypsin-treated cartilage disks with undamaged collagen networks. Studies were carried out in various aqueous solutions to reveal the physical factors that govern aggrecan鈥揷ollagen adhesion. Increasing both ionic strength and [Ca²⁺] significantly increased adhesion, highlighting the importance of electrostatic repulsion and Ca²⁺-mediated ion bridging effects. In addition, we probed how partial enzymatic degradation of the collagen network, which simulates osteoarthritic conditions, affects the aggrecan鈥揷ollagen interactions. Interestingly, we found a significant increase in aggrecan鈥揷ollagen adhesion even when there were no detectable changes at the macro- or microscales. It is hypothesized that the aggrecan鈥揷ollagen adhesion, together with aggrecan鈥揳ggrecan self-adhesion, works synergistically to determine the local molecular deformability and energy dissipation of the cartilage matrix, in turn, affecting its macroscopic tissue properties.