Tribological properties of polyvinyl alcohol hydrogels as artificial articular cartilage

Abstract

An exhaustive scientific investigation has been performed on polymeric hydrogels as potential materials to be used in cartilage tissue repair or replacement. Polyvinyl alcohol (PVA) possesses excellent properties as biocompatibility, low coefficient of friction, low interfacial tension and high permeability to fluids, emerging as an eligible material to be studied for biomedical applications. The main goal of this study was the tribological characterization of PVA hydrogels in lubricated sliding with distilled water and phosphate buffered saline solution (PBS). The influence of hydrogels mechanical properties and operating conditions were considered. Tribological tests were performed on a pin-on-plate tribometer with a linear reciprocating geometry using the PVA/stainless steel 316L and PVA/bovine articular cartilage pairs. Experiments were performed at 37 °C with a constant reciprocating sliding frequency of 1 Hz and applied load of 1 MPa, 2 MPa and 3.5 MPa. For each experiment the friction coefficient was determined and the dominating wear mechanisms analysed by scanning electron microscopy and EDS. PVA showed an excellent performance as possible material for the repair of articular cartilage due to the high level of surface preservation and the very low friction coefficient presented when PBS was used as fluid lubricant. The performed tribological study revealed the high potentiality of PVA hydrogels to be used as artificial articular cartilage.