Modification of Hb-vesicles with oligosaccharide chains

Synthetic glycolipids were introduced into lipid membranes of Hb-vesicles in order to modify the surface of the vesicles with oligosaccharide chains. The resulting suspension of the Hb-vesicles showed good rheological properties and high structural stability. Intervesicular aggregation induced by the addition of Ca²⁺ (5 mM) or dextran (Mw. 40,000) was suppressed due to the excluded volume effect of the oligosaccharide chains which inhibited the access of the surrounding vesicles. After freeze-thawing of the Hb-vesicles with oligosaccharide chains, no diameter change was observed, and leakage of Hb was also suppressed. No change in oxygen binding properties indicates that small molecular or ions as allosteric effectors were not leaked from the vesicles. Therefore, the Hb-vesicles can be stored in a frozen state by the surface modification of the vesicles with the oligosaccharide chains.