Poly(vinylidene fluoride)/poly(styrene-co-acrylic acid) nanofibers as potential materials for blood separation

Abstract

This work reports the association of poly(styrene-co-acrylic acid) random copolymer, P(S-r-AA), with poly(vinylidene fluoride) (PVDF) in the fabrication of electrospun fibers for blood filtration. At first, effort was put into the determination of the styrene/acrylic acid molar ratio in P(S-r-AA) copolymer that would improve best the wetting of nanofibers. With a 19/81 molar ratio, the water contact angle of the modified membrane (M5) was 127 ± 1°, while it was slightly higher for the unmodified membrane (M0, 136 ± 1°). However, the copolymer significantly improved hydration after prolonged contact of the membrane with an aqueous medium, as the swelling ratio increased dramatically from 19% (M0) to 1600% (M5). Nanofibers were all found to be physically and chemically homogeneous, with a pore size increasing from 0.56 μm to 1.25 μm for M0 and M5, respectively, and a regular copolymer distribution on the surface. While no flow could be recorded through M0 with white blood cells (WBCs) concentrate, 10-fold diluted whole blood or whole blood, permeation and separation were achievable with M5. 100%, 100% and 99.99% retention of leukocytes was measured with WBCs concentrate, 10-fold diluted whole blood, and pure whole blood using this membrane. Besides, it allowed to recover 79% of red blood cells. Although effort is still needed to enhance the nanofibers biocompatibility and the RBCs recovery, the results of this study prove that PVDF-based nanofibers have potential to be efficient separation media of whole blood.