Jovtchev S, Stoeff S, Arnold K, Zschörnig O
Department of Physics and Biophysics, Medical Faculty, Medical University Sofia, Sofia, Bulgaria.
Clin Hemorheol Microcirc. 2008;39(1-4):229-33.
Covalent binding of poly(ethylene glycol), abbreviated as PEG, to red blood cells (RBC) surface leads to masking of the RBC blood group determinants and the PEG layer on the cell surface sterically hinders RBC-RBC and RBC-plasma protein interactions. We cross-linked linear mPEG-SPA of various molecular mass (2000, 5000, 20000) to washed human RBC under varying incubation ratios polymer to RBC. The electrophoretic mobility (EM) of the modified RBC decreases with increasing of chain length and concentration of PEG up to 50%. It may reflect the alteration in the surface layer thickness and friction. The aggregation behaviour of the pegylated RBC was studied with the Zeta sedimentation technique modifying the cell-cell interactions pressing them toward each other under centrifugal forces of various magnitudes. As a rule at low centrifugation forces the increase in chain length and concentration of PEG linked to RBC surface reduces the dextran-induced aggregation probably via elevation of the steric repulsion, which counteracts the depletion force generated by the free polymer. This effect was reversed to some extent by elevation of free dextran concentration and centrifugation forces. If cell-cell polymer bridging starts playing a role under these conditions requires further experimental and theoretical investigations.
聚乙二醇（简称为PEG）与红细胞（RBC）表面的共价结合会导致红细胞血型决定簇被掩盖，并且细胞表面的PEG层会在空间上阻碍红细胞与红细胞以及红细胞与血浆蛋白之间的相互作用。我们将不同分子量（2000、5000、20000）的线性甲氧基聚乙二醇琥珀酰亚胺丙酸酯（mPEG-SPA）在不同的聚合物与红细胞孵育比例下交联到洗涤过的人红细胞上。修饰后红细胞的电泳迁移率（EM）随着PEG链长度的增加和浓度增加至50%而降低。这可能反映了表面层厚度和摩擦力的改变。采用Zeta沉降技术研究了聚乙二醇化红细胞的聚集行为，该技术通过在不同大小的离心力下使细胞相互挤压来改变细胞间相互作用。通常，在低离心力下，连接到红细胞表面的PEG链长度增加和浓度升高会降低葡聚糖诱导的聚集，这可能是通过增加空间排斥力来实现的，空间排斥力会抵消游离聚合物产生的排空力。游离葡聚糖浓度和离心力的升高在一定程度上会使这种效应逆转。在这些条件下细胞间聚合物桥接是否开始起作用需要进一步的实验和理论研究。
