Synthesis of Latex-Protein Complexes for Immunoassays

GONZALEZ, V. D. G.; GARCIA, V. S.; VEGA, J. R.; MARCIPAR, I. S.; MEIRA, G. R.; GUGLIOTTA, L. M.

Los Cocos, Córdoba

Simposio; V Simposio Argentino – Chileno de Polímeros - ARCHIPOL ‘09; 2009

Immunodiagnosis latex-protein complexes are useful for detecting pregnancies, rheumatoid arthritis, toxoplasmosis, malaria, brucelosis, and leptospirosis. Immunodiagnosis tests involve specific reactions between an antigen (or antibody) contained in a human fluid and an antibody (or antigen) contained in the latex-protein complex. The particles agglutination process can be visualized either directly or via instrumental methods. Biomolecules are attached onto latex particles either by simple physical adsorption or by covalent coupling. The latex-protein complexes obtained by physical adsorption have low stability and can give unspecified agglutinations, resulting in false diagnosis. Moreover, the complexes are considered of a lower quality, due to the potential desorption and denaturalization of the adsorbed proteins (Hidalgo and Galisteo, 1995). For the chemical coupling of proteins, hydrophilic functionalized latexes of uniform particle size and uniform functional group density are used. Their hydrophilic nature increases the stability of their latex-protein complexes, and it also prevents nonspecific latex-protein interactions (Elwing et al., 1988). The uniformity in particle size and functional density: a) increase the colloidal stability; b) enable a homogeneous distribution of the diagnosis protein onto the particles surface; and c) generate a neat agglutination process. The linkage of proteins is strongly affected by the medium; and its ionic strength or its pH can affect the amount of bound protein (Bale et al., 1989). With the final aim of producing an immunodiagnosis kit for the Chagas disease, the present work describes the sensitization of base latexes with 3 antigenic proteins of Trypanosoma cruzi.