Immobilisation of sulphated hyaluronan for improved biocompatibility

Hyaluronan (Hyal) was modified by the insertion of sulphate to hydroxyl gro ups. A series of heparin-like compounds with controllable properties was ob tained. The physicochemical and biological behaviours of all these sulphate d hyaluronan acids (HyalS(x)) and their complexes with heavy metal ions (Cu 2+ and Zn2+) were investigated. HyalS(x) derivatives showed a good anticoag ulant activity and low platelet aggregation which increased with increasing degree of sulphation. Moreover HyalS(x) and their Cu2+ complexes were demo nstrated to favour the growth of human endothelial cells. However, the util isation of HyalS(x) as a material is hindered by its high solubility in phy siological solution. Our approach to improve its stability was directed to the synthesis of new HyalS(x)-based hydrogels and on the preparation of new biocompatible polymeric surfaces obtained through covalent photoimmobilisa tion of HyalS(x). The reaction of primary ovine chondrocytes and B10D2 endo thelial cells was studied on both matrices in terms of cell number, F-actin and CD44 receptor immunostaining. Analysis of cell movement showed that th e cells respond to HyalS(x) showing good adhesion and spreading. These resu lts suggest that HyalS(x) containing materials could be used as biomaterial s to aid cartilage repair and vessel endothelisation. (C) 2000 Elsevier Sci ence Inc. All rights reserved.