Hemocompatibility of PVDF/PS-b-PEGMA membranes prepared by LIPS process

Abstract

The lack of knowledge on the hemocompatibility of PVDF-based membranes suggested the need for a dedicated study. The present work lays the focus on the effect of polystyrene-b-poly (ethylene glycol) methacrylate (PS-b-PEGMA) on the blood compatibility of PVDF membranes prepared by liquid-induced phase separation. First, the adhesion behavior of three major blood plasma proteins – fibrinogen (FN), γ-globulin and human serum albumin (HSA) – onto the membranes is thoroughly discussed. PS-b-PEGMA acts as a protein repellent, favoring the formation of a hydration layer at the surface of the membranes. A similar result is obtained whether using pure proteins or proteins from a platelet-poor plasma solution. Next, our results suggest that interactions between thrombocytes, erythrocytes and leukocytes with PEGylated membranes are importantly reduced. The mechanism for cell repulsion is believed to be identical as that responsible for protein resistance: the formation of a hydration layer around the ethylene glycol groups minimizes (i) the interactions between the membrane and the proteins constituting the wall of blood cells and (ii) prevents mediation of cells attachment by plasma proteins. Also, the hemolytic activity and the plasma clotting time are reduced and delayed, respectively, supporting the improvement of membranes hemocompatibility with PS-b-PEGMA content. Finally, the copolymer contributes to the resistance of irreversible biofouling due to plasma proteins during filtration. A flux recovery ratio of 91% is obtained for modified membranes while it is only 17% for commercial hydrophobic PVDF membrane and 56% for commercial hydrophilic PVDF membrane, after applying a similar treatment involving the adsorption of plasma proteins. Therefore, PEGylated PVDF membranes presented in this work are hemocompatible and could be used in blood contacting devices.