Heavy metal/toxins detection using electronic tongues

FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOThe growing concern for sustainability and environmental preservation has increased the demand for reliable, fast response, and low-cost devices to monitor the existence of heavy metals and toxins in water resources. An electronic tongue (e-tongue) is a multisensory array mostly based on electroanalytical methods and multivariate statistical techniques to facilitate information visualization in a qualitative and/or quantitative way. E-tongues are promising analytical devices having simple operation, fast response, low cost, easy integration with other systems (microfluidic, optical, etc) to enable miniaturization and provide a high sensitivity for measurements in complex liquid media, providing an interesting alternative to address many of the existing environmental monitoring challenges, specifically relevant emerging pollutants such as heavy metals and toxins.73119FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOSem informaçã

Multilayered Nanostructures Integrated with Emerging Technologies

Surface and interface functionalization are crucial steps to introduce new functionalities in numerous applications, as faster dynamics occur on surfaces rather than bulk. Within this context, the layer-by-layer (LbL) technique is a versatile methodology to controllably form organized nanostructures from the spontaneous adsorption of charged molecules. It enables the assembly of multilayered LbL films on virtually any surface using non-covalent molecular interactions, allowing the nanoengineering of interfaces and creation of multifunctional systems with distinct building blocks (polymers, clays, metal nanoparticles, enzymes, organic macromolecules, etc.). Several applications require thin films on electrodes for sensing/biosensing, and here we explore LbL films deposited on interdigitated electrodes (IDEs) that were 3D-printed using the fusing deposition modeling (FDM) technique. IDEs covered with LbL films can be used to form multisensory systems employed in the analysis of complex liquids transforming raw data into specific patterns easily recognized by computational and statistical methods. We extend the FDM 3D-printing methodology to simplify the manufacturing of electrodes and microchannels, thus integrating an e-tongue system in a microfluidic device. Moreover, the continuous flow within microchannels contributes to faster and more accurate analysis, reducing the amount of sample, waste, and costs

Identification of Pax6-Dependent Gene Regulatory Networks in the Mouse Lens

Lineage-specific DNA-binding transcription factors regulate development by activating and repressing particular set of genes required for the acquisition of a specific cell type. Pax6 is a paired domain and homeodomain-containing transcription factor essential for development of central nervous, olfactory and visual systems, as well as endocrine pancreas. Haploinsufficiency of Pax6 results in perturbed lens development and homeostasis. Loss-of-function of Pax6 is incompatible with lens lineage formation and results in abnormal telencephalic development. Using DNA microarrays, we have identified 559 genes expressed differentially between 1-day old mouse Pax6 heterozygous and wild type lenses. Of these, 178 (31.8%) were similarly increased and decreased in Pax6 homozygous embryonic telencephalon [Holm PC, Mader MT, Haubst N, Wizenmann A, Sigvardsson M, Götz M (2007) Loss- and gain-of-function analyses reveals targets of Pax6 in the developing mouse telencephalon. Mol Cell Neurosci 34: 99–119]. In contrast, 381 (68.2%) genes were differently regulated between the lens and embryonic telencephalon. Differential expression of nine genes implicated in lens development and homeostasis: Cspg2, Igfbp5, Mab21l2, Nrf2f, Olfm3, Spag5, Spock1, Spon1 and Tgfb2, was confirmed by quantitative RT-PCR, with five of these genes: Cspg2, Mab21l2, Olfm3, Spag5 and Tgfb2, identified as candidate direct Pax6 target genes by quantitative chromatin immunoprecipitation (qChIP). In Mab21l2 and Tgfb2 promoter regions, twelve putative individual Pax6-binding sites were tested by electrophoretic mobility shift assays (EMSAs) with recombinant Pax6 proteins. This led to the identification of two and three sites in the respective Mab21l2 and Tgfb2 promoter regions identified by qChIPs. Collectively, the present studies represent an integrative genome-wide approach to identify downstream networks controlled by Pax6 that control mouse lens and forebrain development

Electrical conductivity of Ag-Na ion exchanged soda-lime glass

This paper reports on a study of the influence of silver on the electrical conductivity of Ag-Na ion exchanged soda-lime-silica glass. A glass of 22Na(2)O.8CaO.70SiO(2) (mol %) composition was prepared and silver was introduced into its samples by Ag-Na ion exchange at 350 degrees C for 1 h. The ion exchanged samples were further subjected to a thermal treatment at 500 degrees C for 24 h. Complex impedance diagrams (-Z '' vs. Z' plots) at several temperatures were obtained to calculate the activation energy for the dc electrical conductivity, Ea. The electrical conductivity of the ion exchanged sample is close to that of the pristine sample. The complex impedance plots of this sample show a tail in the low frequency range assigned to the non-uniform distribution of silver in the surface layers and stresses produced by the thermal and chemical temperings. The electrical conductivity of the layers was lower than that of the pristine glass. The further thermal treatment reduced the conductivity of the sample due to the formation of metallic silver nanopartides in the glass matrix and the lower concentration of the mobile Na+ ions. UV-visible optical absorption spectra showed an absorption band at 420 nm attributed to the presence of silver nanoparticles in the thermally treated sample. (C) 2014 Elsevier B.V. All rights reserved.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Langmuir and Langmuir-Blodgett films of low-bandgap polymers

CAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL E NÍVEL SUPERIORFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOLow-bandgap conjugated polymers have provided a considerable increase in organic photovoltaic efficiencies, however, an understanding of class-specific nanostructures, necessary to further improve device qualities, remains scarce. Their self-assembly and associated electronic behaviors in Langmuir-Blodgett (LB) films are used here to provide relationships specific to each polymer, clarifying their structure-property characteristics. The behavior of two low-bandgap polymers based on cyclopentadithiophene (PCPDTBT) and dithienosilole (Si-PCPDTBT) units in the Langmuir trough were investigated and it is shown that it is possible to fabricate nanostructured films of low-bandgap polymers on solid substrates with the LB deposition technique. The polymers were mixed with amphiphilic molecules at well-defined concentrations to improve the formation of the LB films. The polymers were also deposited by drop-casting and LB techniques onto interdigitated electrodes to evaluate their electrical properties, and the LB films were characterized for their optical and morphological properties. It was found that both LB and drop-cast films of PCPDTBT showed higher electrical conductivities than those of Si-PCPDTBT. Importantly, LB films resulted in higher electrical conductivities - by an order of magnitude - compared to their equivalent mixtures with stearic acid in drop-cast films, although drop-cast films without stearic acid gave higher conductivities. This fine-tuning of the molecular architectures of the films is thus demonstrated to directly affect the physical properties and may lead to an improvement in device efficiencies in future applications.67810281034CAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL E NÍVEL SUPERIORFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL E NÍVEL SUPERIORFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOCh748 26805WM2010/20094-1LMF 16557Agências de fomento estrangeiras apoiaram essa pesquisa, mais informações acesse artig