Fabricating hemocompatible bi-continuous PEGylated PVDF membranes via vapor-induced phase inversion

Abstract

Lack of knowledge on their hemocompatibility limit the use of PVDF membranes in biomedical applications. Herein, we investigated the in situ modification of PVDF membranes by a PEGylated copolymer (PS60-b-PEGMA108) using vapor-induced phase separation (VIPS) process. Efforts were first oriented toward the characterization of the effect of copolymer on membrane formation, membranes physical properties and membranes surface chemistry. Then, biofouling was investigated before moving onto the hemocompatibility of membranes. Membranes structure tended to evolve from nodular to bi-continuous with PS60-b-PEGMA108 content, evidencing a change of dominating phenomena during phase inversion (crystallization-gelling vs. non-crystallization gelling), associated to a change of prevailing crystalline polymorph (β-polymorph vs. α-polymorph). Furthermore, the hydration of membranes was importantly enhanced, affecting nano-biofouling: bovine serum albumin, lysozyme and fibrinogen adsorption were drastically reduced, despite rough surfaces, highlighting the efficiency of the copolymer. Bacterial attachment tests revealed that macro-biofouling was inhibited as well. Results of erythrocytes, leukocytes, and thrombocytes adhesion indicated that membranes prepared from a casting solution containing 5wt% copolymer are highly hemocompatible, result supported by low hemolysis ratio (1%) and delay of plasma clotting time. Overall, this study unveils that in situ modification coupled to the VIPS method can readily lead to hemocompatible PVDF membranes.