Browsing by Author "Ferreira, Lucas Franco"

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    Impedimetric immunosensor for rapid and simultaneous detection of chagas and visceral leishmaniasis for point of care diagnosis.
    (2020) Cordeiro, Taís Aparecida Reis; Martins, Helen Rodrigues; Franco, Diego Leoni; Santos, Fred Luciano Neves; Celedon, Paola Alejandra Fiorani; Cantuária, Vinícius Lopes; Lana, Marta de; Reis, Alexandre Barbosa; Ferreira, Lucas Franco
    In this work, a dual detection system based on an impedimetric immunosensor was developed for the first time for the simultaneous detection of anti-Trypanosoma cruzi and anti-Leishmania infantum antibodies in human and dog serum samples. The IBMP 8.1 and rLci1A/rLci2B recombinant antigens were immobilized over the surface of dual screen-printed carbon electrodes (W1 and W2) modified with poly (4-hydroxyphenylacetic acid). Under optimized conditions, the immunosensor recognized specific interactions for anti-T. cruzi antibodies up to a dilution of 1:10,240 and for anti-L. infantum up to 1:5120 in canine serum samples. Relative standard deviation (RSD) values of 2.8% for W1 and 3.6% for W2 were obtained for T. cruzi (W1) and L. infantum antigen (W2) samples in three different electrodes for 3 days (n = 9). The immunosensor was stored at 4 ◦C for 8 weeks, with activity retention of 70.2% in W1 and 78.2% in W2. The results using the recombinant proteins revealed that all antigens discriminated between negative and positive samples (p < 0.0001) in both dog and human groups, as well as no cross-reactivity could be detected among sera with other infections. With this approach, immunosensor-based diagnostic tests achieved 100% accuracy, suggesting that the antigens are eligible to enter Phase-II studies.
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    Label-free electrochemical impedance immunosensor based on modified screen-printed gold electrodes for the diagnosis of canine visceral leishmaniasis.
    (2019) Cordeiro, Taís Aparecida Reis; Gonçalves, Marcus Vinícius do Carmo; Franco, Diego Leoni; Reis, Alexandre Barbosa; Martins, Helen Rodrigues; Ferreira, Lucas Franco
    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.