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09:02
Characterization of Intra-Cartilage Transport Properties of Cationic Peptide Carriers
Published on: August 10, 2020
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Structure and Properties of Cartilage Proteoglycans
Ferenc Horkay1, Peter J Basser1, Anne-Marie Hecht2
1Section on Quantitative Imaging and Tissue Sciences, Eunice Kennedy Schriver National Institute of Child Health and Human Development, National Institutes of Health, 13 South Drive, Bethesda, MD 20892, USA.
Macromolecular Symposia
|May 8, 2018
Summary
Aggrecan, a key cartilage proteoglycan, forms microgels in solution. Adding hyaluronic acid (HA) to aggrecan solutions affects osmotic pressure and microgel dynamics, impacting cartilage structure and function.
Area of Science:
- Biochemistry
- Biophysics
- Materials Science
Background:
- Aggrecan is the most abundant cartilage proteoglycan, characterized by its bottlebrush structure with numerous negatively charged glycosaminoglycan chains.
- These chains, including chondroitin sulfate and keratan sulfate, contribute to aggrecan's functional properties in cartilage.
- Aggrecan interacts with hyaluronic acid (HA) to form large aggregates crucial for cartilage structure and mechanical integrity.
Purpose of the Study:
- To investigate the macroscopic and microscopic behavior of aggrecan solutions and aggrecan-hyaluronic acid complexes.
- To understand the formation and properties of aggrecan microgels in dilute solutions.
- To elucidate the influence of hyaluronic acid on the osmotic and dynamic properties of aggrecan assemblies.
Main Methods:
- Macroscopic properties were studied using osmotic pressure and rheological measurements.
- Microscopic properties were investigated using small angle neutron scattering (SANS), static light scattering (SLS), and dynamic light scattering (DLS).
Main Results:
- In dilute solutions, aggrecan forms microgels composed of loosely connected clusters with diffuse boundaries.
- The osmotic pressure of aggrecan-HA systems decreases as hyaluronic acid concentration increases.
- Dynamic light scattering revealed a relaxation rate varying as q^3 in aggrecan microgels, indicative of internal modes. The aggrecan-HA complex showed slightly faster relaxation rates than pure aggrecan solutions.
Conclusions:
- Aggrecan self-assembles into microgels in dilute solutions, influencing cartilage mechanical properties.
- Hyaluronic acid modulates the osmotic and dynamic behavior of aggrecan assemblies, affecting cartilage hydration and resilience.
- Understanding these molecular interactions is vital for comprehending cartilage physiology and pathology.
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