Injectable synthetic extracellular matrices for tissue engineering and repair.

The development of novel biointeractive hydrogels for tissue engineering1, 2, 3, tissue repair, and release of drugs4 and growth factors5 has attracted considerable attention over the past decade. Our attention has focused on hydrogels based on the extracellular matrix (ECM), a heterogeneous collection of covalent and noncovalent molecular interactions comprised primary of proteins and glycosaminoglycans (GAGs)6. In the ECM, covalent interactions connect chondroitin sulfate (CS), heparan sulfate (HS) and other sulfated GAGs to core proteins forming proteoglycans (PGs). Noncovalent interactions include binding of link modules of PGs to hyaluronan (HA), electrostatic associations with ions, hydration of the polysaccharide chains, and triple helix formation to generate collagen fibrils.