Novel PVP/PVA hydrogels for articular cartilage replacement

Poly(vinyl alcohol) (PVA) hydrogel has been considered as a very interesting and promising material for articular cartilage replacement. The most vital shortcoming of PVA hydrogels is that their mechanical properties are difficult to meet the requirements of articular cartilage. In the present work, blend hydrogels based on PVA and poly (vinyl pyrrolidone) (PVP) were prepared by repeated freezing and thawing method. Such hydrogel had similar internal three-dimensional structure and water content (approximately 75%) as nature articular cartilage. The mechanical and tribological properties were investigated to find out that change of mechanical and tribological properties of PVP/PVA hydrogels were significantly dependent on PVP content and freezing–thawing cycles. The blend hydrogel with 1 wt.% PVP had the best mechanical properties and the friction system consisting of such blend hydrogel and stainless steel ball exhibited a mixed lubrication regime especially under bovine serum lubrication. The results established that such hydrogel would be a novel attractive material for articular cartilage replacement.