Synergistic adsorption of creatinine and p-cresol from simulated serum using zeolites in electrospun fibrous mixed-matrix membranes

In this study, fibrous polyethersulfone (PES) mixed-matrix membranes were prepared by electrospinning, to which fine adsorbents including two zeolites, activated carbon, and graphene oxide were added. They were applied as a hemoperfusion unit for efficient clearance of creatinine and p-cresol from simulated serum. Physicochemical and morphological properties of the prepared fibrous membranes were firstly investigated. Batch adsorption tests revealed that the equilibria of uremic toxins on all fibrous membranes were attained within 4 h. The adsorption isotherms of creatinine and p-cresol in simulated serum (37 °C and pH 7.4), with and without 30 g/L of BSA, could be better described by the Langmuir equation, compared to the Freundlich equation. In contrast to pure adsorbent and PES membrane alone, synergistic adsorption (defined in equation (7) in the text) of creatinine and p-cresol using the fabricated mixed-matrix membranes was observed. In particular, the strongest synergism occurred in creatinine adsorption using the zeolite-incorporated PES membranes, mainly due to the comparable dimensions of the fibers and zeolite particles. The operating stability of as-prepared fibrous membranes was assessed by checking their adsorption ability before and after they were sonicated. The hemolysis tests and viability measurements of human umbilical vein endothelial cells finally indicated that the prepared PES-based mixed matrix membranes were hemo- and bio-compatible.