ROLE OF FILTER SURFACE TENSION IN THE RETENTION OF CELLULAR ELEMENTS BY MICROAGGREGATE BLOOD FILTERS

ABSTRACT

The surface tension of the material composing microaggregate blood filters was determined in order to assess the contribution of surface interactions to the retention of blood cells by these devices. Eight commercially available blood filters were investigated. The filter elements were composed of materials including polyvinyl chloride, polyurethane, dacron, cotton and polyester. The surface tension of these materials was determined using the advancing solidification front technique. In the case of granulocyte concentrates and fresh platelets a striking correlation was shown to exist between the extent of cellular retention and filter material surface tension: the higher the surface tension of the material, the greater the extent of cellular retention in accord with previously published thermodynamic predictions. Filters made of the same material but having a different total surface area retained different amounts of fresh blood cells: the larger the surface area the greater the number of cells retained. The surface tension of the blood filters had no affect on the retention of platelets in stored platelet concentrates.