Glycosaminoglycan (GAGs) are major components of the mammalian extracellular matrix. GAGs such as chondroitin sulfate (CS) and hyaluronic acid (HA) are widely used in tissue engineering, but a major limitation is the poor mechanical properties. A tough and ductile double-network (DN) biopolymer-based hydrogel was developed and characterized. The DN hydrogel was made using methacrylated chondroitin sulfate (MCS), and polyacrylamide (PAAm) or hyaluronic acid. The major conclusion is that MCS/PAAm DN hydrogels have proved to provide excellent toughness and strength for a biomaterial and are comparable to previously developed tough double-network gels of poly(2-acrylamido-2-methylpropane-sulfonic acid) (PAMPS)/PAAm. Further the MCS/PAAm DN had no hysteresis in the first 15% strain after 12 cycles and showed minimal hysteresis at higher strains. Increasing concentrations of MCS also increases the fracture stress but minimizes the fracture strain and the yielding diminishes the yielding phenomenon. Polyethylene (glycol) diacrylate (PEGDA) was added to the MCS first network. PEGDA was previously found to act as a cross-linker in co-polymerizations of MCS and PEGDA. PEGDA increases the modulus with concentration but reduces the fracture properties. Overall, this is the first demonstration of a tough, ductile biopolymer-based network displaying a substantial necking region, demonstrating the generality of this failure mechanism in such DN gel formulations and can be tuned by changing the concentrations and adding a chemical cross-linker. Future strategies are to develop biocompatible GAG-DNs. 

Improving the fracture properties of glycosaminoglycan hydrogels by double network strategy

245th National Meeting (2013)

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