Navegando por Autor "Jorio, Ado"

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    Efficient delivery of DNA into bovine preimplantation embryos by multiwall carbon nanotubes.
    (2016) Munk, Michele; Ladeira, Luiz Orlando; Carvalho, Bruno Campos de; Raposo, Nádia Rezende Barbosa; Serapião, Raquel V.; Quintão, Carolina Capobiango Romano; Silva, Saulo Rodrigues; Soares, Jaqueline dos Santos; Jorio, Ado; Brandão, Humberto de Mello
    The pellucid zone (PZ) is a protective embryonic cells barrier against chemical, physical or biological substances. This put, usual transfection methods are not efficient for mammal oocytes and embryos as they are exclusively for somatic cells. Carbon nanotubes have emerged as a new method for gene delivery, and they can be an alternative for embryos transfection, however its ability to cross the PZ and mediated gene transfer is unknown. Our data confirm that multiwall carbon nanotubes (MWNTs) can cross the PZ and delivery of pDNA into in vitro-fertilized bovine embryos. The degeneration rate and the expression of genes associated to cell viability were not affected in embryos exposed to MWNTs. Those embryos, however, had lower cell number and higher apoptotic cell index, but this did not impair the embryonic development. This study shows the potential utility of the MWNT for the development of new method for delivery of DNA into bovine embryos.
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    Nanomechanics of few-layer materials : do individual layers slide upon folding?
    (2020) Batista, Ronaldo Junio Campos; Dias, Rafael Freitas; Barboza, Ana Paula Moreira; Oliveira, Alan Barros de; Manhabosco, Taíse Matte; Silva, Thiago R. Gomes; Matos, Matheus Josué de Souza; Gadelha, Andreij de Carvalho; Rabelo, Cassiano; Cançado, Luiz Gustavo de Oliveira Lopes; Jorio, Ado; Chacham, Helio; Neves, Bernardo Ruegger Almeida
    Folds naturally appear on nanometrically thin materials, also called “2D materials”, after exfoliation, eventually creating folded edges across the resulting flakes. We investigate the adhesion and flexural properties of single-layered and multilayered 2D materials upon folding in the present work. This is accomplished by measuring and modeling mechanical properties of folded edges, which allows for the experimental determination of the bending stiffness (κ) of multilayered 2D materials as a function of the number of layers (n). In the case of talc, we obtain κ ∝ n 3 for n ≥ 5, indicating no interlayer sliding upon folding, at least in this thickness range. In contrast, tip-enhanced Raman spectroscopy measurements on edges in folded graphene flakes, 14 layers thick, show no significant strain. This indicates that layers in graphene flakes, up to 5 nm thick, can still slip to relieve stress, showing the richness of the effect in 2D systems. The obtained interlayer adhesion energy for graphene (0.25 N/m) and talc (0.62 N/m) is in good agreement with recent experimental results and theoretical predictions. The obtained value for the adhesion energy of graphene on a silicon substrate is also in agreement with previous results.