Synthesis of Composites of Polyurethane Membranes/Polycaprolactone Fibers for Membrane Blood Oxygenators

Membrane blood oxygenators (MBOs) assure in extracorporeal blood circulation the metabolic functions of failing lungs. The technical and medical progress of the MBOs depends on two major factors: (1) hemocompatibility of the membrane/blood interfaces, and (2) enhancement of the flow management/mass transfer associated to the metabolic functions of the lung. Integral asymmetric bi-soft segment polyurethane (PEUU) membranes with polycaprolactone (PCL) as the second soft segment have been studied and showed enhanced hemocompatibility properties. In the present work, integral asymmetric PEUU membranes, containing 10%wt. of PCL (PEUU10), were synthetized by a modified phase inversion method. The synthesis of the composites, PEUU10/PCL, is carried out by the electrospinning of the PCL fibers over the top surface of the PEUU10 membranes dense layer. The electrospinning was performed in an in-house built set-up by applying an electric potential between the metallic syringe-tip with PCL solution and the target plate with a PEUU10 membrane. The solution was continuously fed to the syringe-tip at a constant flow rate and accelerated by the electric field to be deposited over the target. The PEUU10 membrane was attached to a cylindrical support target that allows to tune the fiber deposition conditions by varying the rotation speed. The PEUU10 membranes and the PEUU10/PCL composites were characterized by Scanning electron microscopy (SEM). The performance of the PEUU10/PCL composites in terms of boundary layer disruption, mixing promotion and subsequent oxygen mass transfer enhancement is evaluated in a surrogate system of a MBO.