Serological diagnosis of Toxoplasmosis disease using a fluorescent immunosensor with chitosan-ZnO-nanoparticles.
Medawar-Aguilar, V., Jofre, C. F., Fernandez-Baldo, M. A., Alonso, A., Angel, S., Raba, J., Pereira, S. V. and Messina, G. A.
INQUISAL, Departamento de Quimica, Facultad de Quimica, Bioquimica y Farmacia, Universidad Nacional de San Luis, Chacabuco 917, San Luis, Argentina.
Instituto Tecnologico de Chascomus (IIB-INTECH) CONICET-Universidad Nacional de General San Martin, Camino de Circunvalacion Laguna Km. 6 CC 164, B7130IWA, Chascomus, Provincia de Buenos Aires, Argentina.
INQUISAL, Departamento de Quimica, Facultad de Quimica, Bioquimica y Farmacia, Universidad Nacional de San Luis, Chacabuco 917, San Luis, Argentina. Electronic address: messina@unsl.edu.ar.
This article describes a microfluidic LIF immunosensor for the quantitative determination of anti-Toxoplasma gondii IgG (anti-T. gondii) specific antibodies. The serological detection of these antibodies plays a crucial role in the clinical diagnosis of toxoplasmosis. Zinc oxide nanoparticles (ZnO-NPs) obtained by wet chemical procedure were covered with chitosan and then used to conjugate T-gondii antigens into the central microfluidic channel. Serum samples containing anti-T-gondii IgG antibodies were injected into the immunosensor where they interact immunologically with T. gondii antigens. Bound antibodies were quantified by the addition of anti-IgG antibodies labeled whit alkaline phosphatase (ALP). ALP enzymatically converts the non-fluorescent 4-methylumbelliferyl phosphate (4-MUP) to soluble fluorescent methylumbelliferone that was measured using excitation at 355nm and emission at 440nm. The relative fluorescent response of methylumbelliferone is proportional to the concentration of anti-T. gondii IgG antibodies. The coefficients of variation are less than 4.73% for within-day assays and less than 6.34% for between-day assays. Results acquired by LIF immunosensor agree with those obtained by enzyme-linked immunosorbent assay method, suggesting that the designed sensor represents a promising tool for the quantitative determination of anti-T. gondii IgG antibodies of clinical samples.
Analytical Biochemistry 564-565: 116-122 (2019)