Tribological evaluation of hydrogels for artificial articular cartilage

Abstract

Bacterial cellulose (BC) is a natural and biocompatible gel with unique properties, such as high water holding capacity, ultra-fine fibre network and high strength that make it an interesting material for biotribological purposes. In this work, unmodified BC pellicles were grown from Gluconacetobacter xylinus in order to be used as tribological samples against bovine articular cartilage (BAC) in the presence of phosphate buffered saline (PBS). The tribological assessment was accomplished using reciprocating pin-on-flat tests at 37ºC at constant sliding frequency (1 Hz) and stroke length (8 mm). Contact pressures ranging from 0.8 to 2.4 MPa were applied. The friction coefficient was monitored and the release of total carbohydrates into the lubricating solution was followed by means of the phenol-H2SO4 method as an attempt to evaluate wear losses. Low friction values (~ 0.05) combined with the preservation of the mating surfaces (BC and BAC) indicate the potential of BC to be used as artificial cartilage for articular joints.