Controlled degradation of peptide modified hydrogels improves rate, quality, and quantity of in vivo bone formation

Biodegradability is a critical polymer scaffold characteristic for tissue engineering applications. A scaffold for cell transplantation should provide mechanical support and structure in concert with the needs of newly developing tissue. Alginate hydrogels modified with specific adhesion ligands have previously been used to successfully engineer bone and cartilage tissue in vivo, but show negligible degradation in vitro and in viva. Gamma irradiating the alginate, which decreased the average molecular weight of the polymer chains, increased the rate of hydrogel degradation in viva and fibrous tissue ingrowth. Primary rat calvarial osteoblasts combined with gamma irradiated alginate modified with specific adhesion ligands significantly improved the rate, quality, and quantity of new bone tissue formed in vivo compared to the non-irradiated control condition. Control of both the degradation and adhesion characteristics of a polymer scaffold will be a powerful tool in regulating tissue regeneration processes.