Photochemical surface modification of polystyrene in the presence of cerium(IV) ammonium nitrate: improved binding of proteins, amines and mercaptans in the presence of detergent
By irrdiating various polymer surfaces covered with cerium(IV) ammonium nitrate (CAN) with long-wavelength u.v. light (u.v.-A), which is not absorbed by the polymer, the physical behaviour of the surface is modified. The surface becomes more hydrophilic and there is an improvement in the binding of proteins and low-molecular-mass amines and mercaptans in the pressence of nonionic detergents. Specifically, it is shown that binding of peroxidase-conjugated IgG to treated plates in the presence of Berol EMU-043 is severalfold increased as compared with non-irradiated materials. Furthermore, biotin-mercaptan and biotin-amine reagents bind to the modified material, and this binding is quenched by addition of spermine or benzylmercaptan. By using [/sup 3/H] spermidine it is shown that CAN/u.v.-A treatment also activates polyethylene, polypropylene and polymethyl methacrylate for binding of amines.