Label-free electrochemical impedance immunosensor based on modified screen-printed gold electrodes for the diagnosis of canine visceral leishmaniasis.

Leishmaniasis is a disease with high impact on public health in many countries. Visceral leishmaniasis (VL) is a vectorial zoonosis, with dogs as primary reservoirs in the domestic environment. VL presents high morbidity, mortality and importance in epidemiology in the American continent. In the present study, the first label-free electrochemical impedance immunosensor using screen-printed electrodes (SPEs) for the detection of anti-Leishmania infantum antibodies was developed. The soluble antigens of L. infantum were immobilized on an SPE by a 3-mercaptopropionic acid monolayer. Electrochemical impedance spectroscopy (EIS) was used for detecting bimolecular interactions occurring at the electrode surface. The addition of real samples consisting of canine and human sera positive and negative for VL presented high sensitivity and selectivity through EIS. Based on the results, a sensitive, specific, rapid and simple immunosensor was developed successfully with potential application for the serological diagnosis of leishmaniasis disease.