COVALENT COUPLING OF ANTIBODIES TO ALDEHYDE GROUPS ON POLYMER CARRIERS

The aim of the present work is to prepare and characterize a functiona lized latex with acetal groups on the surface and to obtain the covale nt coupling of an a-CRP IgG protein. The acetal latex was synthesized by means of a core-shell emulsion polymerization in a batch reactor. T he core was a seed of polystyrene and the shell was obtained by terpol ymerization of styrene, methacrylic acid and methacryloylacetaldehyde di(n.methyl)acetal. The latex was characterized by TEM and conductimet ric and potentiometric titration, in order to obtain the particle size distribution and the amount of carboxyl and acetal groups on the surf ace, respectively. Several latex-protein particles with the IgG physic ally or chemically bound to the surface were obtained by modifying the incubation conditions. In the covalent coupling experiments of the Ig G, the protein physically adsorbed was removed by redispersion of the complexes in the presence of a non-ionic surfactant (Tween 20). The la tex-protein complexes were characterized from the electrokinetic point of view with the aim to determine the isoelectric point of the comple xes and to detect any difference in the electric state of the protein when these molecules are physically or chemically coupled to the surfa ce. The final pa rt of th is work was to study the immunoreactivity of several latex-lgG complexes at several experimental conditions. By me asuring the change in the turbidity after the addition of CRP antigen into the dispersion, it was possible to compare the immunoreactivity r esults when the protein is physically or chemically bound to the surfa ce, and to study the effect of the presence of a surfactant in the rea ction medium.