Mechanical properties of polyvinylalcohol/hydroxyapatite cryogel as potential artificial cartilage

The technological advances in material science are not enough to overcome the challenge of construct a material be able to replace the cartilage. The designed material has to meet the mechanical properties of cartilage and has to be also capable to be integrated with the articulation. Articular cartilage damage is a persistent and increasing problem which affects millions of people worldwide. Poly vinyl alcohol (PVA) hydrogels are promising implants, due to their similar properties as soft tissue; however their low mechanical resistance and durability together with its lack to integrate with the surrounding tissue restrict their application in this area. The poor adhesion can be solved by the development a composite hydrogel with bioactive and biocompatible filler, as hydroxyapatite (HA). The aim of this work was to obtain and characterize (physically, chemically and mechanically) PVA/HA composite hydrogels for potential application as articular replacement. Hence, composite hydrogels were prepared by adding of different amounts of HA in an aqueous solution of PVA and subsequent freezing-thawing cycles. It was observed that the addition of HA modified the physical and chemical features of the hydrogel and promoted the material crosslinking and stability. Moreover, it was found that the mechanical properties (compression, tension and nanoindentation) of the hydrogels were improved by the addition of HA. All these result indicate that these materials could be used as a potential cartilage replacement. However, further in vitro and in vivo studies are mandatory for future possible clinical applications and are actually being carried out.