POLYACROLEIN LATEX AS A SOLID-PHASE CARRI ER FOR RADIOIMMUNOASSAY - COMPARISON WITH MICROCRYSTALLINE CELLULOSE AND POLYSTYRENE TEST-TUBE SURFACE

The immunosorbent obtained through a covalent immobilization of antibo dies on a polyacrolein latex was studied in comparison with the sorben ts based on microcrystalline cellulose and with the surface of polysty rene test tubes in a two-center radioimmunoassay for ferritin. It was shown that the polyacrolein latex provides a covalent binding of up to 75 mg protein per g dry polymer with an immobilization efficiency of 50 - 70% and a high effective association constant of immobilized anti bodies (K-a = 4.5 x 10(9) M(-1)). The same parameters for the sorbent based on microcrystalline cellulose were 33 mg/g, 25 - 35%, and 4.3 x 10(8) M(-1) respectively. In the radioimmunoassay for ferritin, the im munosorbents based on polyacrolein latex and cellulose ensured a nearl y the same analytical sensitivity at the level of(0.7 - 0.9) x 10(-13) M ferritin and pointed to the possibility of eliminating the ''hook-e ffect''. Compared to the immunosorbent based on polystyrene test tubes , the advantages of the polyacrolein latex are the decrease in the min imum detectable concentration (increase in analytical sensitivity), th e extension of the dynamical range of analysis, and the absence of the ''hook-effect''.