Navegando por Palavras-chave "Silk fibroin"

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    Immunosensor 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.
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    Silk fibroin organization induced by chitosan in layer-by-layer films: Application as a matrix in a biosensor
    (Elsevier Sci Ltd, 2017) Delezuka, Jorge A. M.; Pavinatto, Adriana; Moraes, Marli L. [UNIFESP]; Shimizu, Flavio M.; Rodrigues, Valquiria C.; Campana-Filho, Sergio P.; Ribeiro, Sidney J. L.; Oliveira, Osvaldo N., Jr.
    In this paper, we show that chitosan may induce conformation changes in silk fibroin (SF) in layer-by-layer (LbL) films, which were used as matrix for immobilization of the enzyme phytase to detect phytic acid. Three chitosan (CH) samples possessing distinct molecular weights were used to build CH/SF LbL films, and a larger change in conformation from random coils to beta-sheets for SF was observed for high molecular weight chitosan (CHH). The CHH/SF LbL films deposited onto interdigitated gold electrodes were coated with a layer of phytase, with which phytic acid could be detected down to 10(-9) M using impedance spectroscopy as the principle of detection and treating the data with a multidimensional projection technique. This high sensitivity may be ascribed to the suitability of the CHH/SF matrix, thus indicating that the molecular-level interactions between chitosan and SF may be exploited in other biosensors and biodevices. (C) 2016 Elsevier Ltd. All rights reserved.
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    Silk 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.
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    Silk 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.