Implantation of encapsulated human septal chondrocytes into immunocompetent mice using alginate microfibers

Cartilage regeneration is a major challenge for researchers because cartilage tissue has limited innate regenerative ability. Encapsulation within an alginate gel has been used widely for 3D scaffolds to generate cartilage-like tissue, but alginate gels have limitations such as poor mechanical properties. In this study, we fabricated alginate microfibers for human septal chondrocyte (HSC) encapsulation and identified the conditions that result in the optimal mechanical properties of the alginate microfibers. In vitro experiments showed that HSCs encapsulated within alginate microfibers maintained >90% viability for 7 days, and the 140μm condition was more effective in terms of HSC proliferation than the 330 and 520μm conditions. In vivo, HSCs differentiated gradually into cartilage tissue over 4 weeks in immunocompetent mice. Importantly, the alginate-encapsulated HSCs were isolated and protected from the host immune response despite xenograft implantation.