Porosity and compatibility of novel polysulfone-/vitamin E-TPGS-grafted composite membrane

Polysulfone (Psf) hollow fiber membranes are widely used for hemodialysis. Despite its popularity as a biomaterial, the hydrophobicity of the polymer is a major concern for blood contact applications. Various blends of the polymer with hydrophilic ligands have been reported in the literature, to achieve desired surface property. To increase hydrophilicity, we report here a hydrophilic polysulfone polymer by covalently coupling vitamin E tocopheryl polyethylene glycol 1000 succinate (Vit E-TPGS or TPGS) and Psf. H-1 NMR confirmed grafting of TPGS to Psf. With a high degree of TPGS substitution, the Psf-g-TPGS was completely hydrophilic, which resulted in no fiber formation alone. Hence, composite membranes were prepared by mixing plain Psf and Psf-g-TPGS in 1.8:1 ratio, which also resulted in a hydrophilic character. This can be tuned toward slightly hydrophilic with a higher ratio. The porosity and biocompatibility of the Psf-g-TPGS (M-III, PTC) were compared against those of unmodified Psf membrane (M-I, Psf) and unmodified Psf-TPGS blend membrane (M-II, PTB). The in vitro cellular compatibility was tested in hepatocarcinoma cell line (HepG2); the cells grown on membrane surface were examined by SEM. Results confirmed that the modified membrane is hydrophilic, is non-toxic, and may have improved efficiency in hemodialysis. Hemocompatibility of M-III, PTC had a slightly better performance over M-I; M-I showed better performance in the cellular attachment, which shows the promising role of the grafted hydrophilic polymer for related biocompatibility applications.