Mixed matrix membranes for toxin removal from blood

Objectives: Chronic kidney failure requires an artificial kidney treatment called hemodialysis. However, not all uremic toxins can be removed from the blood by dialysis and therefore morbidity and mortality of patients are still high. In this work we develop a Mixed Matrix Membrane (MMM) which consists of adsorptive particles imbedded into a porous polymer matrix for selective adsorption and removal of uremic toxins from blood, combining diffusion and adsorption in one step. A particle-free layer is also introduced on the blood contacting side of the MMM to prevent biocompatibility problems caused by direct blood contact with the adsorbent.

Methods: Polyethersulfone based porous MMM with activated carbon particles and a particle-free top layer were prepared by co-casting and subsequent liquid-liquid phase separation. The membranes were characterized by scanning electron microscopy, clean water flux measurements and adsorption capacity experiments with blood model solutions.

Results: Mixed Matrix Membranes with homogenous distribution of carbon particles and with a high clean water permeability were developed. Creatinine, a small uremic toxin, was selectively removed from a blood model solution both via diffusion as well as adsorption by the MMM.

Conclusions: This study shows a proof of principle for Mixed Matrix Membranes as an artificial kidney treatment. The MMM selectively removes toxins via both diffusion and adsorption in one step.