Browsing by Author "Lara, Luciano Roni Silva"

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    Preparation of magnetoliposomes with a green, low-cost, fast and scalable methodology and activity study against S. aureus and C. freundii bacterial strains.
    (2018) Silva, Rosangela Maria Ferreira da Costa e; Lara, Luciano Roni Silva; López Aguilar, Jorge Luis; Andrade, Ângela Leão; Oliveira, Junnia A. C.; Takahashi, Jacqueline Aparecida; Vieira, Henriete da Silva; Matencio, Tulio; Stumpf, Humberto Osório; Domingues, Rosana Zacarias
    A novel, fast, low-cost and scalable methodology to prepare stable magnetoliposomes (MGLs), without the use of organic solvents, is described. The concept of the work is based on the dual use of soy lecithin associated to a new liposome preparation methodology. Soy lecithin was used to coat the nanoparticles of magnetite (Fe3 O4 @lecithin) and for encapsulation of Fe3 O4 @lecithin (Lip-Fe3 O4 @lecithin). Liposomes with size less than 160 nm, polydispersity index of 0.25 and zeta potential of -41 mV, were prepared with the use of autoclave and sonication. The liposomal formulations containing magnetite and stigmasterol (Lip-Fe3 O4 @lecithin, Lip-Stigma and Lip-Stigma-Fe3 O4 @lecithin) were shown to be promising for the application as antibacterial. The liposomal formulation and magnetite were characterized by the following techniques: conventional and high-resolution transmission electron microscopy (TEM/HRTEM), energy-filtered transmission electron microscopy (EFTEM), proton nuclear magnetic resonance (1H NMR), Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRPD), dynamic light scattering (DLS) and zeta potential. The Lip-Fe3 O4 @lecithin had a minimum inhibitory concentration (MIC) of 8.4 µg mL-1 in the presence of 200 Oe magnetic field against S. aureus.
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    Structural, optical, and magnetic evaluation of Co-, Ni-, and Mn-modified multiferroic BiFeO3 ceramics.
    (2021) Sales, Joel Neto Bispo de; Silva, Rafael Tomaz da; Lara, Luciano Roni Silva; Ramos, Sérgio L. L. M.; Soares, Jaqueline dos Santos; Soares, Thiago André Salgueiro; Machado, Giovanna; Manhabosco, Sara Matte; Oliveira, Alan Barros de; Carvalho, Hugo Bonette de; Batista, Ronaldo Junio Campos; Stumpf, Humberto Osório; Manhabosco, Taíse Matte
    Co-, Ni-, and Mn-doped BiFeO3 (BFO) ceramics were synthesized herein through a solid-state reaction. All doped BFO samples exhibit visible-light response, and the Co- and Ni-doped BFO samples present enhanced ferro-magnetic order at room temperature. All doped samples show secondary phases in minor quantities. Optical spectra reveal two absorptions bands, indicating multiple electron transitions for BFO and its secondary phases. M − H hysteresis loops suggest enhanced ferromagnetism in the Co- and Ni-doped BFO samples because of magnetic spinel CFP and NFO phases, respectively, whereas changes in oxygen vacancies and Fe–O–Fe bond angle play minor roles in the ferromagnetic behavior.