Electrospun EVOH/AST-120 hybrid nanofiber membranes for removal of indoxyl sulfate from blood.

Nanofibers containing activated carbon using poly(ethylene--vinyl alcohol) (EVOH) were prepared to remove indoxyl sulfate (IS) from the blood. IS is a urinary toxin that is highly toxic and triggers the progression of chronic kidney disease (CKD). Here, nanofibers containing activated carbon (AST-120), which has been used practically as an adsorbent for indole (a precursor of IS), were fabricated electrospinning for the adsorption and removal of IS from the blood. EVOH containing different ethylene ratios was used as the nanofiber material; moreover, the effect of the ethylene ratio on various properties of the nanofibers, such as surface wettability and the IS adsorption rate, was investigated. As a result, EVOH/AST-120 nanofibers comprising EVOH with a low ethylene ratio exhibited faster IS adsorption behavior. This adsorption behavior agreed well with the pseudo-second-order model, suggesting that the diffusion of IS into the nanofibers is the rate-limiting step of the process of adsorption. Furthermore, the nanofibers successfully reduced the IS concentration in the blood under circulating conditions. Therefore, these EVOH/AST-120 nanofibers are expected to greatly improve the prognosis of patients with CKD when used in combination with the current hemodialysis therapy as an IS-adsorbing filter.