EFFECT OF PROTEOGLYCANS ON HYDROXYAPATITE GROWTH IN-VITRO - THE ROLE OF HYALURONAN

The effect of cartilage proteoglycans on HA seed crystal growth was st udied using a system providing constant supersaturation with respect t o HA. The monomers were much less effective than the aggregates in red ucing the rate of HA growth, which correlates with their affinity for the HA crystals. Hyaluronan, which is a normal constituent of the prot eoglycan aggregates, behaved as a strong inhibitor of HA seed crystal growth and had an affinity constant similar to that of proteoglycan ag gregates. The results indicate that inhibition of HA seed crystal grow th is mediated through the interaction of hyaluronan with HA crystal s urface and that the proteoglycans add to the volume of the adsorbate c ausing steric hindrance.