Navegando por Palavras-chave "Immunosensor"
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- ItemSomente MetadadadosImmunosensor for diagnosis of Alzheimer disease using amyloid-beta 1-40 peptide and silk fibroin thin films(Elsevier Science Bv, 2016) Goncalves, J. M.; Lima, L. R.; Moraes, Marli Leite de [UNIFESP]; Ribeiro, S. J. L.Layer-by-Layer (LbL) films containing silk fibroin (SF) and the 40 aminoacid-long amyloid-beta peptide (A beta 1-40) were prepared with the purpose of developing a new prototype of an electrochemical immunosensor. The film showed a satisfactory growth in quartz substrate and screen-printed carbon electrodes, as observed by UV-vis spectroscopy and cyclic voltammetric, respectively. The peptide immobilized in LbL films in junction with SF shows secondary structure induced, as shown by circular dichroism measurements, favoring the interaction SF/peptide LbL film with the specific antibody. Immunosensor showed a linear response in the presence of the antibody with concentrations from 0 to 10 ng mL(-1) both analyzed by current changes in 0.3 V and voltammogram area. This system can be applied as a new prototype for preliminary diagnosis of Alzheimer's disease. (C) 2016 Elsevier B.V. All rights reserved.
- ItemRestritoImmunosensor for the Diagnostics of Autoimmune Hemolytic Anemia (AIHA) Based on Immobilization of a Monoclonal Antibody on a Layer of Silk Fibroin(American Scientific Publishers, 2019-07) Moraes, Marli L; Vicentini-Oliveira, Josy C; Lima, Lais R; de Souza, Aparecida V G; Oliveira Jr, Osvaldo N; Deffune, Elenice; Ribeiro, Sidney J L; http://lattes.cnpq.br/0639327863515028
- ItemSomente MetadadadosImmunosensors Made with Layer-by-Layer Films on Chitosan/Gold Nanoparticle Matrices to Detect D-Dimer as Biomarker for Venous Thromboembolism(Chemical Soc Japan, 2018) Rodrigues, Valquiria C.; Moraes, Marli L. [UNIFESP]; Soares, Juliana C.; Soares, Andrey C.; Sanfelice, Rafaela; Deffune, Elenice; Oliveira Jr, Osvaldo N.We report on immunosensors to detect D-dimer, a biomarker of venous thromboembolism, which are made with layer-by-layer (LbL) films containing immobilized anti-D-dimer monoclonal antibody alternated with a layer of chitosan/gold nanoparticles (AuNpChi). Detection was due to irreversible adsorption of the antigen D-dimer on its corresponding antibody according to a Langmuir-Freundlich model, thus giving rise to ellipsoidal structures in scanning electron microscopy images whose size and number increased with D-dimer concentration. The chemical groups involved in the adsorption process were inferred from polarization-modulated infrared reflection absorption (PM-IRRAS) through changes in the amide and carbonyl bands. Detection of D-dimer was made with electrical impedance spectroscopy, electrochemical impedance spectroscopy and cyclic voltammetry. The latter was the most sensitive with a detection limit of 9 x 10(-4) mu g/mL, sensitivity of 0.27 x 10(-6) A/mu gmL(-1) with linear increase from 0 to 1 mu g/mL. The selectivity of the immunosensor made with AuNpChi/anti-D-dimer film was verified by noting negligible changes in the cyclic voltammograms when exposed to typical interferents in biological fluids.
- ItemSomente MetadadadosImunossensor para o diagnóstico da Doença de Alzheimer através da detecção do autoanticorpo Anti-βA42(Universidade Federal de São Paulo (UNIFESP), 2020-02-28) Yokomichi, Anna Laura Yuri [UNIFESP]; Moraes, Marli Leite De [UNIFESP]; Universidade Federal de São PauloAlzheimer’s disease (AD) is a progressive neurodegenerative disease, responsible for the most case of dementia. This work offers a promising solution that seeks the early disease diagnosis through the immunosensor development for autoantibody detection against amyloid beta with 42 amino acids (Aβ42). The immunosensor was built by immobilizing Aβ42 with silk fibroin (SF) on screen-printed carbon electrode and gold interdigited electrode for electrochemical and electrical measurement, respectively. Films containing SF and SF with nonspecific peptide were used as control systems. It was observed that antibody (anti-Aβ42) interaction with the immobilized peptide with SF had a different electrical response than antiβA42 interacted with control systems. The data obtained in the previous measurements were treated using Principal Component Analysis. The impedance spectroscopy tests had better results for the film with Aβ42 peptide on SF, there was more signal variation for each anti-Aβ42 concentration. No specific antibody was tested with these immunosensor and the observed behavior was similar to the control films, confirming its specificity. Cyclic voltammetry and impedance tests were performed on film containing Aβ42 with real samples of serum and cerebrospinal fluid, from healthy people and people with Alzheimer’s disease. The immunosensor with Aβ42 peptide on SF can distinguish the positive samples for AD from negative ones, through impedance analytical method, a system that indicating to be a good detector of autoantibody against amyloid beta, showing high sensitivity, specificity and with potential for AD prognosis in real samples.
- ItemSomente MetadadadosSilk fibroin-antigenic peptides-YVO4:Eu3+ nanostructured thin films as sensors for hepatitis C(Elsevier Science Bv, 2016) Lima, Lais R.; Moraes, Marli L. [UNIFESP]; Nigoghossian, Karina; Peres, Maristela F. S.; Ribeiro, Sidney J. L.Nanostructured films prepared by Layer-by-Layer technique and containing silk fibroin, antigenic peptide NS5A-1 derived from hepatitis C virus (HCV) NS5A protein and YVO4:Eu3+ luminescent nanoparticles, were utilized in sensing of hepatitis C. Detection system exploits the biorecognition between the antibody anti-HCV and the antigenic peptide NS5A-1 through changes in luminescence properties. Films deposition was monitored by UV-vis Absorption and Fluorescence Spectroscopy measurements at each bilayer deposited. The Eu3+ luminescence properties were evaluated in the presence of anti-HCV for optical detection of specific antibody and anti-HIV used as negative control. Significant changes in luminescence were observed in the presence of anti-HCV concentrations. A new immunosensor platform is proposed for optical detection of hepatitis C. (C) 2015 Elsevier B.V. All rights reserved.
- ItemSomente MetadadadosSilk fibroin-antigenic peptides-YVO4:Eu3+ nanostructured thin films as sensors for hepatitis C(Elsevier Science Bv, 2016) Lima, Lais R.; Moraes, Marli L. [UNIFESP]; Nigoghossian, Karina; Peres, Maristela F. S.; Ribeiro, Sidney J. L.Nanostructured films prepared by Layer-by-Layer technique and containing silk fibroin, antigenic peptide NS5A-1 derived from hepatitis C virus (HCV) NS5A protein and YVO4:Eu3+ luminescent nanoparticles, were utilized in sensing of hepatitis C. Detection system exploits the biorecognition between the antibody anti-HCV and the antigenic peptide NS5A-1 through changes in luminescence properties. Films deposition was monitored by UV-vis Absorption and Fluorescence Spectroscopy measurements at each bilayer deposited. The Eu3+ luminescence properties were evaluated in the presence of anti-HCV for optical detection of specific antibody and anti-HIV used as negative control. Significant changes in luminescence were observed in the presence of anti-HCV concentrations. A new immunosensor platform is proposed for optical detection of hepatitis C. (C) 2015 Elsevier B.V. All rights reserved.