INTEC   05402
INSTITUTO DE DESARROLLO TECNOLOGICO PARA LA INDUSTRIA QUIMICA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
SYNTHESIS AND CONJUGATION OF COLLOIDAL GOLD PARTICLES FOR IMMUNOCHROMAPHIC STRIPS TO DETECT TOXOPLASMOSIS
Autor/es:
PUJATO, NAZARENA; BERLI, CLAUDIO; PERETTI, LEANDRO E; MIRABALLES, IRIS; PEVERENGO, LUZ; MARCIPAR, IVÁN S.
Lugar:
Córdoba
Reunión:
Congreso; II Brazil?Argentine Microfluidics Congress V Congreso de Microfluídica Argentina; 2019
Institución organizadora:
Microfluídica Argentina - UNC - FAMAF
Resumen:
Toxoplasmosis acquired during the gestation stage, mainly in the first trimester, can produce abortion or induce malformations, hydrocephalus, macro or microcephaly and eye injuries. Proper diagnosis and timely treatment are the best ways to both prevent transplacental transmission and to reduce morbidity and mortality and congenital toxoplasmosis sequels.With the final aim of obtaining strips of lateral flow immunochromatography (LFI) for the early detection of toxoplasmosis, this work presents the synthesis and characterization of colloidal gold nanoparticles, their sensitization with biomolecules, the study of the proper conditions of the process, and the utilization of the conjugate in LFI strips.Different types of biomolecules were evaluated in order to study biorecognition alternatives. The evaluated alternatives include: i) the use of a polyclonal antibody capable of recognizing human antibodies (IgG or IgM) bound to gold particles and the immobilization of antigens (recombinant proteins or mixture of T gondii extract) in the detection line of the strip; ii) the use of antigens (recombinant proteins or mixture of T gondii extract) conjugated to the gold particles and an anti-IgG or anti-IgM polyclonal antibody in the detection line of the strip.For the synthesis of the colloidal particles, the sodium citrate-based reduction of gold tetrachloride (‎‎HAuCl4) was used. Ultrapure water was heated in an Erlenmeyer flask while stirring constantly. Once boiling, the gold salt and then the reducing agent were added. The reaction was continued at 100 °C under stirring until the color change from dark blue to intense red was observed (characteristic color of the desired nanoparticle sizes). The presence of particles with average diameter of 30 nm was confirmed by measuring the light absorbance of the sample and observing the corresponding peak at the light wavelength of 520 nm. The sample was also analyzed by dynamic light scattering, observing a unimodal particle size distribution with the required average diameter.Prior to the conjugation of the particles to the recombinant antigens, the minimum amount of protein necessary to stabilize the gold-protein conjugate before the addition of salt was determined. For the test, an U bottom ELISA plate was used, where different concentrations of antigen and buffers with different pHs were analyzed to obtain the optimum condition for the conjugation reaction, which ensures the stability of the colloidal gold particles.Finally, the obtained conjugates were used in the manufacture of IFL strips and evaluated against positive and negative control sera. Preliminary results are promising and further work is currently in progress.