Molecular Adhesion between Cartilage Extracellular Matrix Macromolecules
Author(s)Rojas, Fredrick P.; Batista, Michael A.; Lindburg, C. Alexander; Dean, Delphine; Grodzinsky, Alan J.; Ortiz, Christine; Han, Lin; ... Show more Show less
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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 ≈ 2.5 μm) 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–collagen 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–collagen interactions. Interestingly, we found a significant increase in aggrecan–collagen adhesion even when there were no detectable changes at the macro- or microscales. It is hypothesized that the aggrecan–collagen adhesion, together with aggrecan–aggrecan self-adhesion, works synergistically to determine the local molecular deformability and energy dissipation of the cartilage matrix, in turn, affecting its macroscopic tissue properties.
DepartmentMassachusetts Institute of Technology. Department of Biological Engineering; Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science; Massachusetts Institute of Technology. Department of Materials Science and Engineering
American Chemical Society (ACS)
Rojas, Fredrick P., Michael A. Batista, C. Alexander Lindburg, Delphine Dean, Alan J. Grodzinsky, Christine Ortiz, and Lin Han. “Molecular Adhesion Between Cartilage Extracellular Matrix Macromolecules.” Biomacromolecules 15, no. 3 (March 10, 2014): 772–780. © 2014 American Chemical Society.
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