Preparation and characterization of PVA-PEEK/PVA-β-TCP bilayered hydrogels for articular cartilage tissue repair

The poly(vinyl alcohol) (PVA) hydrogel is regarded as a potential articular cartilage replacement for its good biocompatibility, high permeability to fluid and load-bearing properties. This work investigated a novel Poly(vinyl alcohol)-polyetheretherketone/Poly(vinyl alcohol)-β-tricalcium phosphate (PVA-PEEK/PVA-β-TCP) bilayered hydrogels by freezing-thawing with biomimetic properties for articular cartilage and subchondral bone is developed. The bilayered hydrogels microarchitecture consists of a highly porous and dense structure, and the internal structure were analyzed by micro-CT. The morphology of the resulting hydrogels was analyzed by scanning electron microscopy (SEM), the enhancement of the mechanical properties of the PVA-PEEK/PVA-β-TCP bilayered hydrogels were demonstrated by mechanical testing. The bilayered structure indicate that a good bonding exist between the two layers, which is known to be a requisite necessary to assure a good integrity and functionality of the osteochondral construct. In addition, in vitro cell culture studies revealed that the hydrogels has no negative effect on the cell viability and proliferation and possess good biocompatibility. Then, the bilayered hydrogels were implanted into the knee joint defect of rabbits and hematoxylin and eosin and immunohistochemical staining. The PVA-PEEK/PVA-β-TCP bilayered hydrogels show good potential for use in the field of articular cartilage repair.