Hypothesis: Graphene oxide (GO)-doping in polyethersulfone hollow fiber membranes (PES HFMs) improves the biocompatibility and separation performance for bioartificial kidney (BAK) application. Experiments: GO was doped in PES HFMs. The physicochemical characterization of the developed HFMs was carried out. The biocompatibility tests including hemocompatibility and cytotoxicity tests, and separation experiments including uremic toxins clearance were performed. Findings: GO-doping resulted in low hemolysis (0.37 +/- 0.15%), prolonged coagulation times, and low SC5b-9 marker level (6.84 +/- 1.7 ng/mL), i.e., significantly improved hemocompatibility of GP HFMs. The monolayer attachment and improved proliferation of kidney cells on the outer surface of GP HFMs were achieved. GO-doping significantly enhanced the separation performance, i.e., high pure water permeability (154 +/- 3 mL/m(2)/h/mmHg) was measured, and similar solute rejection profile as that of the commercial dialyzer membranes was recorded. The clearance of urea, creatinine and phosphorous from the simulated blood was measured to be almost 1.6 to 3.3 times higher than that measured for the commercial membranes. Thus, these results indicated that the GO-doping remarkably improved the performance of the developed GP HFMs thereby making them a potential membrane material for the BAK application. (C) 2017 Elsevier Inc. All rights reserved.