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

• Published in: Mikrochimica acta (1966) 2016-03, Vol.183 (3), p.1203-1210
• Main Authors: Regiart, Matías, Pereira, Sirley V., Bertolino, Franco A., Garcia, Carlos D., Raba, Julio, Aranda, Pedro R.
• Format: Article
• Language: English
• Subjects: Analytical Chemistry; Antibodies; Antigens; Biomarkers; Chagas' disease; Characterization and Evaluation of Materials; Chemistry; Chemistry and Materials Science; Congenital diseases; Diffraction; Electric properties; Electrodes; Electron microscopy; Gold; Hydrogen peroxide; Immunoglobulins; Immunosensors; Medical screening; Microengineering; Nanochemistry; Nanoparticles; Nanotechnology; Original Paper; Protozoa; Viral antibodies; X-rays
• ISSN: 0026-3672; 1436-5073
• DOI: 10.1007/s00604-016-1752-4

The authors describe a sandwich immunosensor for anti-IgM T. cruzi -specific antibodies which are a biomarker for congenital Chagas disease (CCD). A screen-printed carbon electrode (SPCE) was modified with gold nanoparticles (AuNPs) and then functionalized with recombinant shed acute phase antigen (SAPA). The AuNPs/SPCE was characterized by scanning electron microscopy, cyclic voltammetry, and X-ray diffraction. The AuNPs provide an increased active surface area, high conductivity, and improved electrocatalytic characteristics, this resulting in a significant improvement of the detection limit. Following interaction between immobilized SAPA and the target antibodies in the serum sample, secondary antibody (an anti-human IgM-HRP conjugate) and solutions of H 2 O 2 and 4-tert-butylcatechol were added and the enzymatic product was detected at −100 mV (vs. Ag/SPCE). The resulting current was proportional to the anti- T. cruzi IgM antibodies present in the sample and showed a linear trend from 10 to 200 ng mL −1 ( R  = 0.998). The detection limit was 3.03 ng mL −1 . These values demonstrate that this electrochemical immunosensor can be used as an alternative serological method for diagnosis of congenital Chagas disease. Graphical abstract A screen printed carbon electrode was modified with gold nanoparticles functionalized with recombinant shed acute phase antigen (SAPA). The resulting biosensor was applied to the quantification of antibodies against anti-IgM T. cruzi that are biomarkers for congenital Chagas disease.