Biosensors for Efficient Diagnosis of Leishmaniasis: Innovations in Bioanalytics for a Neglected Disease

The need for reliable, fast diagnostics is closely linked to the need for safe, effective treatment of the so-called neglected diseases The list of diseases with no field adapted diagnostic tools includes leishmaniasis, shigella, typhoid, and bacterial meningitis Leishmaniasis, in particular, is a parasitic disease caused by Leishmania spp transmitted by infected phlebotomine sandfly, which remains a public health concern in developing countries with ca 12 million people infected and 350 million at risk of infection Despite several attempts, methods for diagnosis are still noneffective, especially with regard to specificity due to false positives with Chagas' disease caused by Trypanosoma cruzi Accepted golden standards for detecting leishmamasis involve isolation of parasites either microscopically, or by culture, and in both methods specimens are obtained by invasive means Here, we show that efficient distinction between cutaneous leishmaniasis and Chagas' disease can be obtained with a low cost biosensor system made with nanostructured films contaming specific Leishmania amazonensis and T cram antigens and employing impedance spetroscopy as the detection method This unprecedented selectivity was afforded by antigen antibody molecular recognition processes inherent in the detection with the immobilized antigens, and by statistically correlating the electrical Impedance data, which allowed distinction between real samples that tested positive for Chagas' disease and leishmaniasis Distinction could be made of blood serum samples containing 10-5 mg/mL of the antibody solution in a few minutes The methods used here are generic and can be extended to any type of biosensor, which is important for an effective diagnosis of many other diseases