Flexible porous discs by radiation polymerization method for enzyme immunoassay of alpha-fetoprotein

New porous discs for enzyme immunoassay of alpha-fetoprotein (AFP) have been prepared by radiation polymerization of various monomers at low temperature. The activity (optical density) of immobilized anti-AFP disc varied with irradiation temperature, anti-AFP concentration, and the hydrophilicity of monomer, in which copolymerization of hydrophilic 2-hydroxyethyl methacrylate and hydrophobic monomers at low temperature below 0 degrees C gave a high activity. The immobilized anti-AFP disc was flexible and had a porous structure. The immobilized anti-AFP discs in dry state are convenient for storage. The minimum serum volume in the assay was 5 microliter. A good correlation (r = 0.98) was noted between AFP concentrations measured by ratio immunoassay and enzyme immunoassay with immobilized anti-AFP disc. The mean recovery of AFP (16-80 ng) added to serum was 95-110%.