Permeation of blood cells from umbilical cord blood through surface-modified polyurethane foaming membranes

Blood cell permeation of umbilical cord blood (UCB) through surface-modified foamed polyurethane membranes having carboxylic group (PU-COOH) with different pore sizes (i.e., 5, 8.9 and 12 μm) was investigated. Red blood cells and platelets can permeate through PU-COOH membranes with any pore sizes analyzed, while leukocytes and hematopoietic stem and progenitor cells (HSPCs) cannot permeate through PU-COOH membranes with permeation ratio of less than 5%. Several recovery solutions (e.g., 20% dextran, 0.5 wt% serum albumin solution, plasma solution) were evaluated for the isolation of several blood cells including HSPCs from PU-COOH membranes after UCB permeated through the membranes. Recovery ratios of leukocytes were relatively low through PU-COOH membranes having pore size (r) = 5 μm, while higher recovery ratio of RBCs was observed than that of leukocytes. The recovery ratio of HSPCs was found to be 8-27% depending on the membrane pore sizes and recovery solution. The recovery ratio of HSPCs from UCB (8-27% in this study) was found to be less than that from peripheral blood reported previously (60-80% [A. Higuchi, M. Sekiya, Y. Gomei, M. Sakurai, W.-Y. Chen, S. Egashira, Y. Matsuoka, Separation of hematopoietic stem cells from human peripheral blood through modified polyurethane foaming membranes, J. Biomed. Mater. Res.: A 85A (4) (2008) 853-861]). This suggests that the purification of HSPCs form UCB is significantly difficult compared to that from peripheral blood, because of high expression of adhesion proteins of HSPCs in UCB.