Alkali blue 6B-derivatized poly(EGDMA/HEMA) microbeads for bilirubin removal from human plasma

Alkali Blue 6B-derivatized poly(EGDMA-HEMA) microbeads were used as a specific sorbent for bilirubin removal from human plasma. Poly(EGDMA-HEMA) microbeads were produced by a modified suspension copolymerization technique. Alkali Blue 6B was covalently immobilized to the poly(EGDMA-HEMA) microbeads via condensation reactions between the aromatic amine groups of the dyes and the hydroxyl groups of the HEMA, under alkaline conditions. Bilirubin adsorption was investigated from hyperbilirubinemic human plasma on the poly(EGDMA-HEMA) microbeads containing different amounts of attached Alkali Blue 6B, (between 8.0-23.7 mu mol/g). The non-specific bilirubin adsorption on the underivatized poly(EGDMA-HEMA) microbeads were 0.32 mg/g from human plasma. High adsorption rates were observed at the beginning, and the adsorption equilibrium were then gradually achieved in about 30-60 minutes. Much higher bilirubin adsorption values, up to 6.8 mg/g, were obtained with the Alkali Blue 6B-derivatized microbeads especially at 37 degrees C. The numbers of (as mu mols) bilirubin molecules coupled to albumin molecules on the sorbent microbeads were in the range of 10-15, which showed that bilirubin molecules were preferentially adsorbed to the sorbent beads through the ligand, i.e. Alkali Blue 6B. Bilirubin adsorption increased with increasing temperature.