An electrochemical immunosensor for anti-T. cruzi IgM antibodies, a biomarker for congenital Chagas disease, using a screen-printed electrode modified with gold nanoparticles and functionalized with shed acute phase antigen

SIRLEY V. PEREIRA; JULIO RABA; SIRLEY V. PEREIRA; JULIO RABA; MATÍAS REGIART; CARLOS D. GARCIA; MATÍAS REGIART; CARLOS D. GARCIA; FRANCO A. BERTOLINO; PEDRO ARANDA; FRANCO A. BERTOLINO; PEDRO ARANDA

MIKROCHIMICA ACTA

SPRINGER WIEN

Lugar: Viena; Año: 2016 vol. 183 p. 1203 - 1210

0026-3672

The authors describe a sandwich immunosensor foranti-IgM T. cruzi-specific antibodies which are a biomarkerfor congenital Chagas disease (CCD). A screen-printed carbonelectrode (SPCE) was modified with gold nanoparticles(AuNPs) and then functionalized with recombinant shed acutephase antigen (SAPA). The AuNPs/SPCE was characterizedby scanning electron microscopy, cyclic voltammetry, andX-ray diffraction. The AuNPs provide an increased activesurface area, high conductivity, and improved electrocatalyticcharacteristics, this resulting in a significantimprovement of the detection limit. Following interaction betweenimmobilized SAPA and the target antibodies in theserum sample, secondary antibody (an anti-human IgM-HRPconjugate) and solutions of H2O2 and 4-tert-butylcatecholwere added and the enzymatic product was detected at−100 mV (vs. Ag/SPCE). The resulting current was proportionalto the anti-T. cruzi IgMantibodies present in the sampleand showed a linear trend from 10 to 200 ng mL−1(R = 0.998). The detection limit was 3.03 ng mL−1. Thesevalues demonstrate that this electrochemical immunosensorcan be used as an alternative serological method for diagnosis