Dênio Emanuel Pires Souto
State University of Campinas
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Featured researches published by Dênio Emanuel Pires Souto.
Biosensors and Bioelectronics | 2013
Dênio Emanuel Pires Souto; Jussara Vieira da Silva; Helen Rodrigues Martins; Alexandre Barbosa Reis; Rita de Cassia Silva Luz; Lauro T. Kubota; Flavio Santos Damos
In this work, a surface plasmon resonance (SPR) immunosensor was developed using an 11-mercaptoundecanoic acid (11-MUA) modified gold SPR sensor chip for the detection of anti-Leishmania infantum antibodies. The soluble antigens of L. infantum were securely immobilized on an SPR gold disk by an 11-MUA self-assembled monolayer. Cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and scanning electrochemical microscopy (SECM) techniques were employed in the characterization of the antigen immobilization. After the immunosensor construction, canine serum positive for visceral leishmaniasis was added to its surface and showed significant variation in the SPR angle, indicating excellent sensitivity of the technique for antigen-antibody interaction detection. Moreover, the addition of negative serum was accompanied by a smaller response, demonstrating that the immunosensor shows good specificity against anti-L. infantum antibodies. Therefore, this work demonstrates the successful development of an SPR sensor for anti-L. infantum antibodies detection in short time, showing a great perspective as a sensing system of visceral leishmaniasis in endemic regions.
Biosensors and Bioelectronics | 2015
Dênio Emanuel Pires Souto; Aliani Moura Fonseca; José T.C. Barragan; Rita de Cássia Silva Luz; Hélida Monteiro de Andrade; Flavio Santos Damos; Lauro T. Kubota
In this work, an SPR immunosensor was developed to elucidate the reaction kinetics between a protein of unknown function in Leishmania infantum (hypothetical C1 protein) and specific antibodies of the visceral leishmaniasis (VL). A platform, which is based on layer-by-layer assembly was formed by cysteamine in combination with a fourth-generation poly(amidoamine) dendrimer (PAMAM(G4)) on gold surface for the immobilisation of the protein. This film resulted in amplification of the signal of SPR. Then, a kinetic model based on a bivalent ligation suggested that the reaction between the C1 protein and the anti-C1 antibody occurs in two steps. The value of the equilibrium dissociation constant (KD1×KD2=1.64×10(-7) mol L(-1)) demonstrated high binding affinity between the biomolecules. Furthermore, low limits of detection (LOD=7.37 nmol L(-1)) and quantification (LOQ=7.83 nmol L(-1)) were presented with the proposed SPR immunosensor. Afterwards, the addition of real samples consisting of positive and negative canine sera for VL was accompanied by high sensitivity and selectivity by SPR immunosensor. Therefore, this study quantitatively demonstrated the strong antigenic character of a hypothetical protein and consequently its potential use in the immunodiagnosis of the VL.
Analytical Sciences | 2015
Neuma das Mercês Pereira; Fernando Mota de Oliveira; Nara Rúbia Pereira; Rodrigo M. Verly; Dênio Emanuel Pires Souto; Lauro T. Kubota; Auro Atsushi Tanaka; Flavio Santos Damos; Rita de Cássia Silva Luz
This work describes the highly sensitive detection of organophosphorus pesticides employing the cobalt(II) 4,4,4,4-tetrasulfo-phthalocyanine (CoTSPc) macrocycle complex, carbon nanotubes (CNT), and 1-methyl-3-octylimidazolium tetrafluoroborate (OMIM[BF4]). The technique is based on enzyme acetylcholinesterase (AChE) inhibition. The composite was characterized by scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy, and amperometry. The AChE was immobilized on the composite electrode surface by cross-linking with glutaraldehyde and chitosan. The synergistic action of the CoTSPc/CNT/OMIM[BF4] composite showed excellent electrocatalytic activity, with a low applied potential for the amperometric detection of thiocholine (TCh) at 0.0 V vs. Ag/AgCl. The calculated catalytic rate constant, k(cat), was 3.67 × 10(3) mol(-1) L s(-1). Under the optimum conditions, the inhibition rates of these pesticides were proportional to their concentrations in the ranges of 1.0 pmol L(-1) to 1.0 nmol L(-1) (fenitrothion), 2.0 pmol L(-1) to 8.0 nmol L(-1) (dichlorvos), and 16 pmol L(-1) to 5.0 nmol L(-1) (malathion).
Nano Letters | 2017
Richard Janissen; Prasana Sahoo; Clelton A. Santos; Aldeliane M. da Silva; Antonio A.G. von Zuben; Dênio Emanuel Pires Souto; Alexandre D.T. Costa; Paola Celedon; Nilson Ivo Tonin Zanchin; D. B. Almeida; Douglas Soares de Oliveira; Lauro T. Kubota; Carlos L. Cesar; Anete Pereira de Souza; M. A. Cotta
Electrically active field-effect transistors (FET) based biosensors are of paramount importance in life science applications, as they offer direct, fast, and highly sensitive label-free detection capabilities of several biomolecules of specific interest. In this work, we report a detailed investigation on surface functionalization and covalent immobilization of biomarkers using biocompatible ethanolamine and poly(ethylene glycol) derivate coatings, as compared to the conventional approaches using silica monoliths, in order to substantially increase both the sensitivity and molecular selectivity of nanowire-based FET biosensor platforms. Quantitative fluorescence, atomic and Kelvin probe force microscopy allowed detailed investigation of the homogeneity and density of immobilized biomarkers on different biofunctionalized surfaces. Significantly enhanced binding specificity, biomarker density, and target biomolecule capture efficiency were thus achieved for DNA as well as for proteins from pathogens. This optimized functionalization methodology was applied to InP nanowires that due to their low surface recombination rates were used as new active transducers for biosensors. The developed devices provide ultrahigh label-free detection sensitivities ∼1 fM for specific DNA sequences, measured via the net change in device electrical resistance. Similar levels of ultrasensitive detection of ∼6 fM were achieved for a Chagas Disease protein marker (IBMP8-1). The developed InP nanowire biosensor provides thus a qualified tool for detection of the chronic infection stage of this disease, leading to improved diagnosis and control of spread. These methodological developments are expected to substantially enhance the chemical robustness, diagnostic reliability, detection sensitivity, and biomarker selectivity for current and future biosensing devices.
Clinica Chimica Acta | 2016
João Gabriel Guimarães Luz; Dênio Emanuel Pires Souto; Girley F. Machado-Assis; Marta de Lana; Rita de Cássia Silva Luz; Olindo Assis Martins-Filho; Flavio Santos Damos; Helen Rodrigues Martins
BACKGROUND We defined the methodological criteria for the interpretation of the results provided by a novel immunoassay based on surface plasmon resonance (SPR) to detect antibodies anti-Trypanosoma cruzi in human sera (SPRCruzi). Then, we evaluated its applicability as a diagnostic tool for Chagas disease. METHODS To define the cut-off point and serum dilution factor, 57 samples were analyzed at SPRCruzi and the obtained values of SPR angle displacement (ΔθSPR) were submitted to statistical analysis. Adopting the indicated criteria, its performance was evaluated into a wide panel of samples, being 99 Chagas disease patients, 30 non-infected subjects and 42 with other parasitic/infectious diseases. In parallel, these samples were also analyzed by ELISA. RESULTS Our data demonstrated that 1:320 dilution and cut-off point at ∆θSPR=17.2 m° provided the best results. Global performance analysis demonstrated satisfactory sensitivity (100%), specificity (97.2%), positive predictive value (98%), negative predictive value (100%) and global accuracy (99.6%). ELISA and SPRCruzi showed almost perfect agreement, mainly between chagasic and non-infected individuals. However, the new immunoassay was better in discriminate Chagas disease from other diseases. CONCLUSION This work demonstrated the applicability of SPRCruzi as a feasible, real time, label free, sensible and specific methodology for the diagnosis of Chagas disease.
ChemElectroChem | 2017
Everson T.S.G. da Silva; Dênio Emanuel Pires Souto; José T.C. Barragan; Juliana de Fátima Giarola; Ana Carolina Mazarin de Moraes; Lauro T. Kubota
Electroanalysis | 2012
Eric Oliveira Faria; Antônio Carlos Viera Lopes Junior; Dênio Emanuel Pires Souto; Fernando Roberto Figueiredo Leite; Flavio Santos Damos; Rita de Cássia Silva Luz; Alexandre Soares dos Santos; Diego Leoni Franco; Wallans Torres Pio dos Santos
Journal of Solid State Electrochemistry | 2013
Jussara Vieira da Silva; Delton Martins Pimentel; Dênio Emanuel Pires Souto; Rita de Cássia Silva Luz; Flavio Santos Damos
Journal of Electroanalytical Chemistry | 2013
Danielle Diniz Justino; Ana Luísa Almeida Lage; Dênio Emanuel Pires Souto; Jussara Vieira da Silva; Wallans Torres Pio dos Santos; Rita de Cássia Silva Luz; Flavio Santos Damos
Sensors and Actuators B-chemical | 2015
João Gabriel Guimarães Luz; Dênio Emanuel Pires Souto; Girley F. Machado-Assis; Marta de Lana; Lauro T. Kubota; Rita de Cássia Silva Luz; Flavio Santos Damos; Helen Rodrigues Martins