Immobilisation of sulphated hyaluronan for improved biocompatibility

Hyaluronan (Hyal) was modified by the insertion of sulphate to hydroxyl groups. A series of heparin-like compounds with controllable properties was obtained. The physicochemical and biological behaviours of all these sulphated hyaluronan acids (HyalS(x)) and their complexes with heavy metal ions (Cu2+ and Zn2+) were investigated. HyalS(x) derivatives showed a good anticoagulant activity and low platelet aggregation which increased with increasing degree of sulphation. Moreover HyalS(x) and their Cu2+ complexes were demonstrated to favour the growth of human endothelial cells. However, the utilisation of HyalS(x) as a material is hindered by its high solubility in physiological 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 photoimmobilisation of HyalS(x). The reaction of primary ovine chondrocytes and B10D2 endothelial cells was studied on both matrices in terms of cell number, F-actin and CD44 receptor immunostaining. Analysis of cell movement showed that the cells respond to HyalS(x) showing good adhesion and spreading. These results suggest that HyalS(x) containing materials could be used as biomaterials to aid cartilage repair and vessel endothelisation. (C) 2000 Elsevier Science Inc. All rights reserved.