ATOMIC-FORCE MICROSCOPIC STUDIES OF HYLAN AND HYALURONAN

Samples of hyaluronan and hylan have been examined by atomic force mic roscopy (AFM). All samples were deposited from aqueous solutions on to freshly cleaved mica surfaces, air dried, and then imaged under butan ol. At a relatively high concentration (10 mu g ml(-1)) all samples fo rmed similar entangled networks, whose detailed structures were influe nced by the drying process. Upon dilution (1 mu g ml(-1)) the hyaluron an networks dispersed, revealing individual molecules or small aggrega tes. However upon the same dilution the formaldehyde cross-linked hyal uronan (hylan) retains the large aggregated structures. These aggregat es are believed to be the structures responsible for the useful rheolo gical properties of hylan which underpin its medical application in th e viscosupplementation of osteoarthritis diseased joints. Copyright (C ) 1996 Elsevier Science Ltd