Efficient Continuous Flow Washing of Red Blood Cells for Exogenous Agent Loading Using a Hollow Fiber Plasma Separator

Abstract

Red blood cells (RBCs) are naturally occumng and biodegradable and are therefore ideal in vivo exogeneous agent (EA) camers. Before being loaded with the EAs, the RBCs are washed, a process that normally involves repeated centrifugation with an iso-osmotic solution. Washing the RBCs can be achieved more efficiently and rapidly using a capillary hollow fiber plasma separator until the blood is 99.5% protein free. Here, a separator area of 0.25 m2 was preferentially selected over a 0.5 m2 device because the reduction in RBC washing time associated with the latter was considered insufficient to justify the use of the more costly (0.5 m2) separator. Mathematical modelling of this continuous flow system indicates that washing time is mainly dependent on the volume of blood to be processed and the filtration rate. Using the separator, 300 ml of blood can be washed in less than 15 min.