Sakai H, Hamada K, Takeoka S, Nishide H, Tsuchida E
Department of Polymer Chemistry, Waseda University, Tokyo, Japan.
Biotechnol Prog. 1996 Jan-Feb;12(1):119-25. doi: 10.1021/bp950068w.
Hemoglobin vesicles (HbV) as red cell substitutes were prepared from a purified carbonylhemoglobin (HbCO) solution and a lipid mixture composed of phospholipids, cholesterol, and alpha-tocopherol. The diameter was controlled to 251 +/- 87 nm using an extrusion method; the vesicles penetrated through the membrane filters with regulated pore sizes. After the ligand exchanging reaction (HbCO-->HbO2), the oxygen affinity (P50) of HbV was 32 Torr, which was controlled with the coencapsulation of pyridoxal 5'-phosphate. The rate of metHb formation in HbV was nonenzymatically reduced with the coencapsulation of DL-homocysteine. The Hb concentration of the HbV suspension, which was dispersed in a phosphate buffered saline solution (pH 7.4), was controlled at 10 g/dL. At this concentration, the total lipid concentration was 6.2 g/dL and the viscosity, 2.6 cP (230 s-1), was lower than that of the blood (4.4 cP). The HbV suspension showed a typical non-Newtonian flow for a particle dispersion and agreed well with the Casson model. The viscosity at shear rates lower than 23 s-1 showed a maximum with increasing the mixing ratio of human blood, plasma, or albumin, while no maximum was observed for the mixture with washed red blood cells. The aggregates of HbV are formed by interaction with plasma proteins, including albumin, while the aggregates reversibly dissociate at higher shear rate.
血红蛋白囊泡（HbV）作为红细胞替代物，是由纯化的羰基血红蛋白（HbCO）溶液和由磷脂、胆固醇及α-生育酚组成的脂质混合物制备而成。采用挤压法将其直径控制在251±87nm；这些囊泡能够穿透具有特定孔径的膜过滤器。配体交换反应（HbCO→HbO₂）后，HbV的氧亲和力（P50）为32 Torr，通过共包封5'-磷酸吡哆醛对其进行控制。通过共包封DL-同型半胱氨酸，非酶促降低了HbV中高铁血红蛋白的形成速率。分散于磷酸盐缓冲盐水溶液（pH 7.4）中的HbV悬浮液的血红蛋白浓度控制在10 g/dL。在此浓度下，总脂质浓度为6.2 g/dL，粘度为2.6 cP（230 s⁻¹），低于血液的粘度（4.4 cP）。HbV悬浮液对于颗粒分散体表现出典型的非牛顿流体特性，并且与卡森模型吻合良好。在剪切速率低于23 s⁻¹时，粘度随着人血、血浆或白蛋白混合比例的增加而出现最大值，而与洗涤过的红细胞混合时未观察到最大值。HbV的聚集体是通过与包括白蛋白在内的血浆蛋白相互作用形成的，而这些聚集体在较高剪切速率下会可逆解离。
