Dialysis/adsorption bifunctional thin-film nanofibrous composite membrane for creatinine clearance in portable artificial kidney

In this study, we proposed a facile strategy for the lightweight design for portable artificial kidney by using a novel dialysis/adsorption bifunctional thin-film nanofibrous composite (TFNC) membrane, which consisting of polyvinyl alcohol (PVA) hydrogel as a separation layer and polyacrylonitrile (PAN) nanofibrous membrane with UiO-66-(COOH)2 nanoparticles as a porous affinity substrate were developed to effectively remove creatinine and substantially reduce the volume of dialysate in dialysis process simultaneously. Here, as-synthesized UiO-66(COOH)2 nanoparticles were strung through PAN nanofibers using colloid-electrospinning technique to prepare necklace-like nanofibrous affinity membrane for creatinine adsorption. The obtained PAN/UiO-66-(COOH)2 nanofibrous membrane (PAN-U) with optimum UiO-66-(COOH)2 loading (60 wt%) exhibited encouraging maximum adsorption capacities (54 mg/g) based on Langmuir isotherm models and pseudo-second-order kinetic models. In addition, the simulated dialysis results demonstrated that 62.8% of creatinine were eliminated and over 98% of bovine serum albumin (BSA) were rejected. Furthermore, the PVA/PAN-U TFNC membrane not only improved the clearance of creatinine in simulated blood, but also efficiently maintained the concentration of creatinine in simulated dialysate at a very low level compared to the pure PVA/PAN TFNC membrane. More importantly, the usage of dialysate in volume for PVA/PAN-U TFNC membranes in dialysis was only one tenth of that for PVA/PAN TFNC membranes but with very comparable dialysis performance. Therefore, the introduction of adsorption function in TFNC hemodialysis membrane may facilitate the development of the lightweight of portable artificial kidney.