Photopolymerization of hydrogels for cartilage tissue engineering

Regeneration of damaged tissues by cell-based strategies has attracted much interest in various tissue engineering applications. For the repair of small cartilage defects, in situ encapsulation of stem cells in injectable, photopolymerizable hydrogels can be used to facilitate new cartilage formation with minimal invasive surgery. In this study, poly(ethylene glycol) diacrylate (PEGDA) hydrogels embedded with Wharton's Jelly mesenchymal stromal cells (WJMSCs) were developed by UV exposure and served as an in vitro model. We demonstrated that the cell viability was more than 60% on day 1 and remained relatively similar on day 8. The decrease in water uptake ability of PEGDA hydrogels without cells was noticeable after incubation in aqueous environment for 2 weeks, suggesting a loss of gel matrix. Taken together, the photopolymerization approach can potentially be applied to deliver stem cells locally at defect sites in vivo to stimulate tissue regeneration.