Bioaffinity adsorption has a unique and powerful role as a support tool in the removal of toxic substances from human plasma. Synthetic hollow-fiber membranes have advantages as support matrices in comparison to conventional hemoperfusion columns because they are not compressible and they eliminate internal diffusion limitations. In this study, Cibacron Blue F3GA was covalently attached onto commercially available microporous polyamide hollow-fiber membranes for bilirubin removal from hyperbilirubinemic human plasma. Different amounts of Cibacron Blue F3GA were attached on the polyamide hollow-fibers by changing the dye-attachment conditions, i.e., initial dye concentration, addition of sodium carbonate, and sodium chloride. The maximum amount of Cibacron Blue F3GA attachment was obtained at 42.5 mumol g(-1) when the hollow fibers were treated with 3 M HCl for 30 min before performing the dye attachment. The nonspecific bilirubin adsorption on the unmodified polyamide hollow-fiber membranes was 0.65 mg g(-1) from human plasma. Higher bilirubin adsorption capacities, of up to 39.7 mg g(-1), were obtained with the Cibacron Blue F3GA-attached polyamide hollow-fiber membranes. Further increase in bilirubin adsorption was obtained as 48.9 mg g(-1). Bilirubin molecules interacted with these adsorbents directly. Contribution of albumin adsorption on the bilirubin adsorption was much pronounced. Bilirubin adsorption increased with increasing temperature and maximum adsorption was observed at 37degreesC.