The influence of Gelatin/PCL ratio and 3-D construct shape of electrospun membranes on cartilage regeneration

Scaffolds play an important role in directing three-dimensional (3-D) cartilage regeneration. Our recent study reported the potential advantages of electrospun gelatin/polycaprolactone (GT/PCL) membranes in regenerating 3-D cartilage. However, it is still unknown whether the changes of GT/PCL ratio have significant influence on 3-D cartilage regeneration. To address this issue, the current study prepared three kinds of electrospun membranes with different GT/PCL ratios (70:30, 50:50, 30:70). Adhesion and proliferation of chondrocytes on the membranes were examined to evaluate biocompatibility of the membranes. Cartilage with different 3-D shapes was engineered to further evaluate the influences of GT/PCL ratio on cartilage regeneration. The current results demonstrated that all the membranes with different GT/PCL ratios presented good biocompatibility with chondrocytes. Nevertheless, the high PCL content in the membranes significantly hampered early 3-D cartilage formation at 3 weeks in vivo. Unexpectedly, at 12 weeks, all the cylinder-shaped constructs formed mature cartilage-like tissue with no statistical differences among groups. To our surprise, ear-shaped cartilage regeneration obtained quite different results again: the high PCL content completely disrupted cartilage regeneration even at 12 weeks, and only the least PCL content group formed homogeneous and continuous cartilage with a satisfactory shape and elasticity similar to human ear. All these results indicated that the high PCL content was unfavorable for 3-D cartilage regeneration, especially for the cartilage with a complicated shape, and that GT/PCL 70:30 might be a relatively suitable ratio for ear-shaped cartilage regeneration. The research models established in the current study provide detailed information for cartilage and other tissue regeneration based on electrospun GT/PCL membranes.