(582k) Aggrecan As a Chondroinductive Signal in Interpenetrating Network Hydrogels for Cartilage Tissue Engineering

Rennerfeldt, D., University of Kansas
Gehrke, S. H., University of Kansas
Detamore, M., University of Kansas

We recently introduced interpenetrating network (IPN) hydrogels composed of agarose and poly(ethylene glycol) diacrylate (PEGDA) as a promising material for cartilage tissue engineering.  We have shown that swelling and mechanical properties of such IPNs can be tuned by selecting appropriate monomer concentrations and PEGDA molecular weights while maintaining encapsulated chondrocyte viability.  In the current study, we investigated a higher molecular weight than we have previously and found that IPNs consisting of 15% w/v PEGDA (molecular weight = 10 kDa) and 2% w/v agarose exhibited nearly a four-fold increase in compressive modulus over single-network PEGDA gels (197 kPa vs. 56.8 kPa) with only a slight decrease in swelling ratio (11.8, vs. 16.8 in pure PEGDA gels). 

In addition, we have recently shown that the incorporation of aggrecan, a proteoglycan largely responsible for the stiffness and swelling properties of cartilage, improved encapsulated chondrocyte viability and matrix synthesis in agarose/PEGDA IPNs.  In our presentation, we will report the findings of a study in progress with a different, more clinically relevant cell source: bone marrow stromal cells (BMSCs).  The aggrecan has not adversely affected the swelling ratio or the mechanical performance of the IPNs, as expected.  Therefore, the results of viability and gene expression assays from our ongoing studies will allow us to test our hypothesis that we may be able to control the cell response independent of the already superior mechanical performance of the IPNs.