Immobilization of superoxide dismutase/catalase onto polysulfone membranes to suppress hemodialysis-induced oxidative stress: A comparison of two immobilization methods

Abstract

a b s t r a c tThe objective of this study is to improve the blood compatibility of polysulfone (PSF) based hemodialysis membranes through generating antioxidative surfaces with superoxide dismutase (SOD)/catalase (CAT) enzyme couple immobilization. Enzymes were attached both covalently and ionically on the plasma treated and polyethyleneimine (PEI) deposited membranes, respectively. The loss of enzymes from PEI modified surface at the end of 4 h was found to be relatively higher during storage in phosphate buffered saline (PBS) at pH 7.4 when compared to the enzymes on the plasma treated surface. The kinetic studies indicated that SOD catalyzed the reaction in the diffusion-limited regime at all substrate concentrations and its inactivation by hydrogen peroxide was prevented in the presence of CAT. SOD/CAT coated PSF membranes were capable of reducing the levels of reactive oxygen species in blood and can significantly prolong activated partial thromboplastin time. In addition, both the adsorption of human plasma proteins and platelet activation on all modified membranes decreased significantly compared to the unmodified PSF membranes. Proposed modification methods did not affect high permeability, high mechanical strength or the non-toxic properties of the PSF membranes.

Enhanced biocatalytic sustainability of laccase by immobilization on functionalized carbon nanotubes/polysulfone membranes

“…The immobilization of laccase can be considered the best of two worlds, since the separation and reuse of this costly biocatalyst becomes possible, while maintaining, or even enhancing its catalytic activity. As mentioned above, there are already studies reporting the use of enzymes immobilized both on PSf and on CNT-based membranes [29][30][31][32]. Yet, to the best of our knowledge, the use of CNT-PSf membranes for laccase immobilization has not been reported in the literature.…”

Immobilization of Superoxide Dismutase on Polyelectrolyte‐Functionalized Titania Nanosheets

“…In addition, enzyme cascades containing SOD, catalase, or other peroxidase enzymes have been prepared, for which these natural biocatalysts were confined in silica nanoparticles, polymeric vesicles, or nanocontainers to mimic the cellular environment and to achieve complete decomposition of ROS into molecular oxygen and water. Antioxidant enzymes have also been covalently linked to polymeric chains to obtain such antioxidant cascades …”

Understanding and tuning of polymer surfaces for dialysis applications

“…Enhanced hemocompatibility and cytocomptability properties have been obtained by blending citric acid grafted polyurethane with polyethersulfone . Superoxide dismutase/catalase on polysulfone (PSf) membranes has also been explored to reduce oxidative stress . The shift from naturally occurring cellulose acetate‐based membranes to synthetic polymeric materials resulted in the reduction of complement activation arising due to dialysis .…”