Desenvolvimento de imunossensor para detecção específica de Leishmanioses em eletrodo de grafite com ouro eletrodepositado

Abstract

This work describes the methodology for electrochemical diagnosis of Leishmaniasis (LSH), it suppresses cross-reaction of Chagas disease (DC). Cross-reactions happen in commercially available (ELISA) tests and thus do not allow correct beginning and / or early treatment. Knowing the sensitivity of the sensor, total antigens tested in the ELISA were methodologically appropriate to the sensor. There were used 3 kinds of screen-printed electrodes: gold, graphite and graphite with electrodeposited gold film to observe biomolecular interaction in the work’s electrode and recognizing the samples. Antibodies present in serum from patients with diverse types of Chagas' Disease and Leishmaniases were chosen. The electrochemical analyses took place from the redox analysis of Ferri solution/Potassium ferrocyanide. The results showed that the graphite electrode with gold electrodeposited film guaranteed effective adsorption of the total antigens so that the epitope of specific recognition for Leishmaniasis occurred efficiently and without cross-reaction with the evaluated Chagas disease. The oxidation current peaks reduced linearly after the recognition, and still being able to notice the discrimination between kinds of diseases. Pool of sera or specific kinds (digestive, cardiac, undetermined Chagas / Acute and chronic Leishmaniasis) presented remarkable discrimination in the immunosensor. Comparative analyses with indirect ELISA were performed with the same groups, presenting cross reactions. Furthermore, the sensor presented relative stability within 5 days. Thus, we presented an innovative proposal of an immunosensor that suppressed the cross reaction to Chagas disease for specific detection of Leishmaniasis.