Adipose-derived stem cells (ADSCs) were purified from mice adipose-tissue cell solutions by the conventional culture method and the membrane filtration (i.e., batch-type filtration and perfusion-type filtration) method. The ADSCs expressing the mesenchymal stem cell marker CD73 were concentrated in a recovery solution through one sheet of polyurethane (PU) foaming membranes with a pore size of 11 mu m, and in a permeate solution through five sheets of Nylon mesh filters with a pore size of 11 mu m, by the perfusion-type filtration method. This provided a concentration of cells expressing the marker that was 1.7 times higher than that of cells in the primary adipose-tissue cell solution. The ADSCs in the recovery solution that went through the PU foaming membranes but not through the Nylon mesh filters showed greater adipogenic and osteogenic differentiation ability than the cells contained in the primary adipose-tissue cell solution. The perfusion-type filtration effectively recovered ADSCs with a greater ability to differentiate into adipocytes and osteoblasts than the cells recovered by batch-type filtration. These results suggested that the ADSCs with adipogenic and osteogenic differentiation ability tended to adhere to PU membranes but not to Nylon mesh filters when using perfusion-type filtration. The relationship between the ratio of cells expressing the mesenchymal stem cell surface marker (i.e., CD73) and the adipogenic and osteogenic differentiation ability of the cells was also investigated. (C) 2010 Elsevier B.V. All rights reserved.