LAYER-CONTROLLED HEMOGLOBIN VESICLES BY INTERACTION OF HEMOGLOBIN WITH A PHOSPHOLIPID ASSEMBLY

Hemoglobin vesicles, which encapsulated concentrated hemoglobin (Hb) w ith a bilayer of ipalmitoylphosphatidylcholine/cholesterol/palmitic ac id, were prepared under various preparation conditions in order to dec rease the number of bilayers (n) constructing the vesicle and increase the Ho concentration in the interior of the vesicle ([Hb](in)). n dec reased when the surface potential of the bilayer became more negative because of the electrostatic repulsion between the bilayers, while wit h a changing xi-potential of Hb from positive to negative, [Hb](im) sh owed a precipitous fall because of the electrostatic repulsion between Hb and the surface of the bilayer. A temperature decrease leads to a quality increase in the Hb vesicles ([Hb]/[lipid]) in spite of the [Hb ](in) decrease by the viscosity increase of the Hb solution. This is e xplained by the effective reduction of n due to the reduction in membr ane fluidity and the protonation of Hb.