Porous fish collagen for cartilage tissue engineering

Cartilage defects repair is still a challenge in clinical practice until now. Although many breakthroughs have been achieved in cartilage repair using tissue engineering technology, there are still no scaffolds available for large-scale clinical applications. Currently, fish collagen (FC) is a natural source that is considered as an alternative to mammal-derived collagen in engineering cartilage tissue due to its excellent biocompatibility, suitable biodegradability, lack of immunogenicity, rich sources, low cost and minimal risk of transmitting zoonoses, which implies great potential for use in cartilage regeneration. Herein, we successfully prepared three-dimensional porous FC scaffolds from three different concentrations of FC (0.5%, 1% and 2%) by freeze-drying technology. Our results indicated that increasing the FC concentration resulted in comparable levels of suitable biodegradability and good biocompatibility but lead to a concurrent decrease in pore size and porosity and a significant increase in water absorption capacity and mechanical properties; further, initial scaffold dimension was only sustained in the 2% FC concentration. Moreover, the in vivo immunological evaluation suggested that the FC scaffold evoke low immunogenicity. In addition, our results confirmed that the porous FC scaffold facilitated cartilage formation both in vitro and when placed subcutaneously in rabbits. The gross and autopsy outcomes at 12 weeks postoperation suggested that the porous FC scaffold achieved superior cartilage repair effect than what was observed in the empty group with no scaffold. Overall, our results demonstrated that porous FC scaffolds represent a promising prospective natural material for use in engineering cartilage for clinical applications.