Morphology of Cross linked Hyaluronic Acid Porous Hydrogels

Hydrogels, based on hyaluronic acid or hyaluronan (HA), are gaining attention as possible cell-scaffolding materials for the regeneration of a variety of tissues. This article describes how HA, a naturally occurring polymer, has been crosslinked to reduce its degradation rate and freeze dried to produce porous materials suitable for tissue engineering. The resulting pore architecture has been assessed as a function of freezing temperature and freezing rate, type of crosslinkers, and methods used in the crosslinking process. On comparing the average densities of crosslinked and uncrosslinked scaffolds, it is apparent that the chemical modification increases sponge density and wall thickness of the pores while decreasing the pore size. The mechanical response of the modified materials has been investigated by equilibrium-swelling measurements and compression tests. These materials have an average pore size ranging from 167 to 215 mu m, which suggests that they would be a suitable temporary site for cell proliferation. The materials exhibit moderate mechanical integrity and are expected to be capable of withstanding physiological stresses in vivo. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 120: 1040-1049, 2011