of the latex-protein complexes requires the study of their The present work deals with the study of the colloidal stability colloidal stability, as this aspect is very important when and immunoreactivity of acetal-functionalized latex particles covlooking for its application in the field of clinical diagnostics, ered by different amount of IgG a-CRP protein. This protein has where one of the two main requirements is colloidal stability been previously coupled onto the acetal particle surface by covaof the latex particles covered by protein. However, there lent binding, and it was possible to obtain latex-protein particles are not many studies on protein chemical adsorption which with different degrees of coverage by this protein. The sensitized complete the characterization of the latex-protein samples latex particles were resuspended under several conditions (differincluding their colloidal stability and, if so, the results cannot ent pH and ionic strength values), and their colloidal stability was be generalized to other polymer supports (2, 3) and have to studied by particle size measurements. The latex-protein complexes obtained by covalent binding of the protein show a good be studied specifically, especially in the case of acetal latex colloidal stability at neutral pH and high ionic strength (200 mM), with noncharged groups on the surface.
which is a first condition for their application in the immunodiag-Another requirement for the application of these comnostic field. As a final part of this work, the immunoreactivity of plexes in clinical diagnostics is the immunoreactivity of the several complexes was studied following the changes in the turproteins after adsorption or coupling on the particle surface. bidity after the addition of CRP antigen. The immunoreactivity of Although this could be a simple study, again only a scarce these complexes depends on their colloidal stability, and treatment number of works complete the immunological application with a nonionic surfactant is also important. The surface structure with the immunoreactivity studies (4, 5), and the results of the latexes has a significant role in the immunological behavior cannot be generalized from one to other systems. By covalent of the complexes because a very high surface charge density can binding, the protein can be adsorbed in such a way that the prevent the aggregation of the sensitized particles in the presence of the antigen molecules. The latex-protein complexes obtained active sites of the protein molecule are directed toward the by covalent binding show a good immunological response which solution, where they can react with the antigens present in is not disturbed by the presence of a nonionic surfactant in the this solution. Thus, the covalent binding can be a method that reaction medium and is stable with time.