Quantitation of immunoglobulin adsorption to plastics

Adsorption of 125I-labelled rabbit IgG to plastics (cellulose nitrate, polyallomer, polystyrene, polyvinyl) was primarily dependent on initial antibody concentration and, to a lesser extent, on time allowed for adsorption. The highest concentration tested (100 μg/ml) gave the highest quantities adsorbed after 18 h at room temperature. This concentration, however, gave the lowest percent adsorption (6.5 to 12.0%) of the initial amount. IgG concentration of 10 μg/ml resulted in 25.0 to 65.1% adsorption over the same time period; at 1 μg/ml, 47.0 to 96.6% of the initial amount was adsorbed. All of the plastics tested adsorbed IgG to approximately the same degree, with the exception of cellulose nitrate. This plastic adsorbed 32 to 49% less than the others, under maximal adsorption conditions.