Osteochondral regeneration using an oriented nanofiber yarn-collagen type I/hyaluronate hybrid/TCP biphasic scaffold

Osteochondral defects affect both the articular cartilage and the underlying subchondral bone, but poor osteochondral regeneration is still a daunting challenge. Although the tissue engineering technology provides a promising approach for osteochondral repair, an ideal biphasic scaffold is in high demand with regards to proper biomechanical strength. In this study, an oriented poly(l-lacticacid)-co-poly(ε-caprolactone) P(LLA-CL)/collagen type I(Col-I) nanofiber yarn mesh, fabricated by dynamic liquid electrospinning served as a skeleton for a freeze-dried Col-I/Hhyaluronate (HA) chondral phase (SPONGE) to enhance the mechanical strength of the scaffold. In vitro results show that the Yarn Col-I/HA hybrid scaffold (Yarn-CH) can allow the cell infiltration like sponge scaffolds. Using porous beta-tricalcium phosphate (TCP) as the osseous phase, the Yarn-CH/TCP biphasic scaffold was then assembled by freeze drying. After combination of bone marrow mesenchymal stem cells, the biphasic complex was successfully used to repair the osteochondral defects in a rabbit model with greatly improved repairing scores and compressive modulus.