(116be) We "Knee"d to Look at What We're Losing, Too! - the Effect of Mechanical Loading and Hydrogel Structure on the Release of Extracellular Matrix Components

Tissue engineering is a promising field for addressing the issue of the inability of cartilage to heal. Although many scaffolds have been used to support cartilage regeneration, functional tissue with native properties has not been achieved, thus many methods have been employed to stimulate this growth and organization. For example, dynamic mechanical compression has seen success in encouraging chondrocytes (cartilage cells) to produce tissue with superior properties compared to non-loaded samples.

A reoccurring issue with loading scaffolds is the enhanced release of extracellular matrix (ECM) components that comprise cartilage tissue. To examine this problem in more detail, two common ECM components (chondroitin sulfate and hyaluronic acid) were loaded in poly(ethylene glycol) (PEG) based hydrogels in the presence and absence of dynamic mechanical loading. ECM release as a function of gel structure and loading parameters, such as frequency and duration, was examined.

Gel crosslinking density significantly affected the rate of release of ECM components from the hydrogel, where higher crosslinked gels resulted in decreased release. The frequency of mechanical loading also affected the release of ECM components, but only when water content and mesh size was decreased. One strategy to overcome this problem was to design a peptide than could be covalently linked to the hydrogel in order to attach to these ECM components. Initial studies show interaction between this peptide and ECM components, resulting in decreased release when scaffolds were dynamically loaded.