New sorbent for bilirubin removal from human plasma: Cibacron Blue F3GA-immobilized poly(EGDMA-HEMA) microbeads.

Cibacron Blue F3GA-immobilized poly(EGDMA-HEMA) microbeads were investigated as a specific sorbent for bilirubin removal from human plasma. The poly(EGDMA-HEMA) microbeads were prepared by a modified suspension copolymerization technique. Cibacron Blue F3GA was covalently coupled to the poly(EGDMA-HEMA) microbeads via the nucleophilic reaction between the chloride of its triazine ring and the hydroxyl groups of the HEMA molecule, under alkaline conditions. Bilirubin adsorption was investigated from hyperbilirubinemic human plasma on the poly(EGDMA-HEMA) microbeads containing different amounts of immobilized Cibacron Blue F3GA, (between 5.0-16.5 micromol/g). The non-specific bilirubin adsorption on the unmodified poly(EGDMA-HEMA) microbeads were 0.32 mg/g from human plasma. Higher bilirubin adsorption values, up to 14.8 mg/g, were obtained with the Cibacron Blue F3GA-immobilized microbeads. Bilirubin molecules interacted with these sorbents directly. Contribution of albumin adsorption on the bilirubin adsorption was pronounced. Bilirubin adsorption increased with increasing temperature.

Protein A carrying PMMA microbeads: adsorption of cholesterol and HlgG from human plasma.

Cholesterol and HIgG adsorbed from human plasma obtained from a hypercholesterolemic patient, onto protein A-immobilized polymethyl-methacrylate uniform microbeads carrying different amounts of protein A (0.264-1.682 mg protein A/g PMMA, or 0.66-4.2 mg protein A/m2 PMMA) were investigated in batchwise experiments. There was no interaction between protein A molecules and cholesterol when cholesterol aqueous solutions were used. However, there was significant cholesterol and HIgG adsorption from the plasma obtained from a patient with hypercholesterolemia. The maximum amounts of cholesterol and HIgG adsorbed were 3.96 micromol cholesterol/g PMMA (5.4 mg cholesterol/g PMMA) and 0.242 micromol IgG/g PMMA (35.4 mg IgG/g PMMA).

Protein A carrying monosize PMMA microbeads for the removal of HIgG from human plasma.

Protein A-incorporated polymethylmethacrylate (PMMA) microbeads were investigated for specific removal of HIgG from human plasma. The microbeads were prepared by a phase inversion polymerization, and activated by periodate oxidation. Protein A was then incorporated by covalent binding onto these microbeads through hydroxyl groups coming from the stabilizer. The amount of incorporated protein A was controlled by the initial concentrations of protein A in the immobilization medium and pH. The maximum protein A immobilization of 0.615 mg protein A/g PMMA, was observed at a pH of 9.5 corresponding to an initial protein A concentration of 0.1 mg/ml. There was no HIgG adsorption onto the plain PMMA microbeads, while high HIgG adsorptions of up to 32 mg HIgG/g PMMA were achieved with human plasma.

Protein A immobilized polyhydroxyethylmethacrylate beads for affinity sorption of human immunoglobulin G.

Protein A immobilized polyhydroxyethylmethacrylate (PHEMA) microbeads were investigated for the specific removal of HIgG from aqueous solutions and from human plasma. PHEMA microbeads were prepared by a suspension polymerization technique and activated by CNBr in an alkaline medium (pH 11.5). Protein A was then immobilized by covalent binding onto these microbeads. The amount of immobilized protein A was controlled by changing pH and the initial concentrations of CNBr and protein A. The maximum protein A immobilization was observed at pH 9.5. Up to 3.5 mg protein A/g PHEMA was immobilized on the CNBr activated PHEMA microbeads. The maximum HIgG adsorption on the protein A immobilized PHEMA microbeads was observed at pH 8.0. The non-specific HIgG adsorption onto the plain PHEMA microbeads was low (about 0.167 mg of HIgG/g PHEMA). Higher adsorption values (up to 6.0 mg of HIgG/g PHEMA) were obtained in which the protein A immobilized PHEMA microbeads were used. Much higher amounts of HIgG (up to 24.0 mg of HIgG/g PHEMA) were adsorbed from human plasma.