Probing nanomechanics of aggrecan and the aggrecan-rich pericellular matrix of chondrocytes in cartilage

The mechanical properties of articular cartilage are associated with the extracellular matrix network of type II collagen and the proteoglycan, aggrecan, which in combination provide the tensile, shear, and compressive stiffness of the tissue. While the collagen network mainly provides resistance to tensile and shear deformation, aggrecan enmeshed within this network contributes significantly to the tissue's compressive and shear properties under equilibrium as well as dynamic loading conditions. Aggrecan has a "bottle-brush" structure that includes -100 negatively charged chondroitin sulfate glycosaminoglycan (CS-GAG) chains attached covalently to a core protein. Electrostatic interactions between these GAGs contribute to the compressive and shear stiffness of the tissue. Variations in the structure of aggrecan and its GAG constituents are known to exist as a function of tissue age, disease, and species. Using atomic force microscopy (AFM), we directly visualized the nanometer scale structure of aggrecan deposited on a 2-D substrate, including the first high resolution imaging of individual GAG chains along the core protein. We also visualized and quantified the differences in structure between aggrecan obtained from fetal epiphyseal and mature nasal bovine cartilages.

Department dc:contributor.department

Massachusetts Institute of Technology. Biological Engineering Division.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2005

Author dc:creator

• Ng, Laurel Jean

Advisor dc:contributor.advisor

• Alan J. Grodzinsky and Christine Ortiz.

• Biological Engineering Division.

Statement dc:rights

• MIT theses are protected by copyright. They may be viewed, downloaded, or printed from this source but further reproduction or distribution in any format is prohibited without written permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/33863

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/33863