This article is a U.S. Government work, and as such, is in the public domain in the United States of America.
Probing interactions between aggrecan and mica surface by the atomic force microscopy†
Article first published online: 16 SEP 2010
Copyright © 2010 Wiley Periodicals, Inc.
Journal of Polymer Science Part B: Polymer Physics
Volume 48, Issue 24, pages 2575–2581, 15 December 2010
How to Cite
Chandran, P. L., Dimitriadis, E. K., Basser, P. J. and Horkay, F. (2010), Probing interactions between aggrecan and mica surface by the atomic force microscopy. J. Polym. Sci. B Polym. Phys., 48: 2575–2581. doi: 10.1002/polb.22132
- Issue published online: 11 NOV 2010
- Article first published online: 16 SEP 2010
- Manuscript Accepted: 27 JUL 2010
- Manuscript Revised: 7 JUL 2010
- Manuscript Received: 27 MAY 2010
- atomic force microscopy;
- osmotic pressure
Aggrecan is a bottlebrush shaped macromolecule found in the extracellular matrix of cartilage. The negatively charged glycosaminoglycan (GAG) chains attached to its protein backbone give aggrecan molecules a high charge density, which is essential for exerting high osmotic swelling pressure and resisting compression under external load. In solution, aggrecan assemblies are insensitive to the presence of calcium ions, and show distinct osmotic pressure versus concentration regimes. The aim of this study is to investigate the effect of ionic environment on the structure of aggrecan molecules adsorbed onto well-controlled mica surfaces. The conformation of the aggrecan was visualized using Atomic Force Microscopy. On positively charged APS mica the GAG chains of the aggrecan molecules are distinguishable, and their average dimensions are practically unaffected by the presence of salt ions. With increasing aggrecan concentration they form clusters, and at higher concentrations they form a continuous monolayer of conforming molecules. On negatively charged mica, the extent of aggrecan adsorption varies with salt composition. Understanding aggrecan adsorption onto a charged surface provides insight into its interactions with bone and implant surfaces in the biological milieu. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2010