Latex of Immunodiagnosis for Detecting the Chagas Disease. II. Chemical Coupling of Antigen Ag36 onto Carboxylated Latexes

GONZALEZ, V. D. G.; GUGLIOTTA, L. M.; MEIRA, G. R.

JOURNAL OF MATERIALS SCIENCE-MATERIALS IN MEDICINE

Springer

Año: 2007

0957-4530

A novel immunodiagnosis reagent for detecting the Chagas Disease was developed, by chemical coupling of antigen Ag36 of Trypanosoma cruzi onto two (carboxylated and core-shell) latexes. The coupling reactions involved the use of a carbodiimide intermediate. Bovine serum albumin (BSA) was used as a model protein for determining the appropriate conditions for its physical and chemical coupling. BSA showed an increased adsorption onto the base carboxylated latexes, with respect to a PS latex without carboxyl groups. The chemical bonding experiments only involved the carboxylated latexes. With BSA, the final density of covalently-bound protein was 2.30 mg/m2. In addition, around 55% of the total linked protein was chemically-coupled, and the reaction was little affected by the pH. With Ag36, the final density of covalently-bound protein was 2.44 mg/m2, around 80% of the total linked protein was chemically-coupled, and the chemical coupling was maximum at pH = 5 (i.e., close to the isoelectric point).