Polystyrene spheres are widely used in radioimmumoassay kit

but it is limited by weak physical adsorption of proteins and the hard control of the amount of adsorpted proteins.The acrolein was grafted on the surface of polystyrene spheres via gamma induced pre irradiation technique.The induced aldehyde groups could react with the amino groups of proteins to form Schiff base

through which trypsin and 125 I-labeled antibody were successfully immobilized on the polystyrene spheres by chemical bond.Comparing with the polystyrene blank

the acrolein grafted polystyrene spheres obviously enhanced the amount of immobilized proteins.So by using this method

the radioimmunoassay kit could be improved

but it is better to change to another monomer with aldehyde group because acrolein is irritant and easy to induce oxo-addition reaction with polystyrene.