Examinando por Autor "Tello, A."

Mostrando 1 - 2 de 2
  • Miniatura
    Ítem
    Synthesis and morphological characterization of nanocomposite based on anodic TiO2 nanotubes and poly(N-maleoyl Glycine-CO-Acrylic acid)
    (Sociedad Chilena de Quimica, 2017) Oyarzún, D.P.; Pizarro, G.D.C.; Asenjo, A.; Tello, A.; Martin-Trasanco, R.; Zúñiga, C.; Sánchez, J.; Arratia-Perez, R.
    In this study, we examined the synthesis, and characterization of TiO2/poly(N-maleoylglycine-co-acrylic acid) (TiO2/poly(MG-co-AA)) nanocomposite. The nanocomposite was prepared by the dispersion of TiO2 nanotubes in a water solution of the polymer (3% w/w) and then it was lyophilized. The nanocomposite was characterized by FTIR and Raman spectroscopies. The incorporation of TiO2 nanotubes to the polymeric matrix was determined by transmission electron microscopy (TEM) from which TiO2 nanotubes in the inner of copolymer with diameters ranging between 90 and 100 nm were observed. The overall morphology of the previously synthetized nanotubes was determined by scanning electron microscopy (SEM). For the nanocomposite system, the morphology was studied by atomic force microscopy (AFM) from which a grain shape structure was observed. This process resulted in a new nanocompsite material with an average grain diameter estimated by SEM and AFM ranging between 210-240 nm. It was observed that the nanotubes were homogeneously dispersed within the polymeric matrix. The prepared material could be suitable in the design of electronic devices and additionally could have potential applications as biomaterial.
  • Miniatura
    Ítem
    Synthesis of salt-stable fluorescent nanoparticles (quantum dots) by polyextremophile halophilic bacteria
    (Nature Publishing Group, 2019-12) Bruna, N.; Collao, B.; Tello, A.; Caravantes, P.; Díaz-Silva, N.; Monrás, J. P.; ÓrdenesAenishanslins, N.; Flores, M.; Espinoza-Gonzalez, R.; Bravo, D.; Pérez-Donoso, J. M.
    Here we report the biological synthesis of CdS fluorescent nanoparticles (Quantum Dots, QDs) by polyextremophile halophilic bacteria isolated from Atacama Salt Flat (Chile), Uyuni Salt Flat (Bolivia) and the Dead Sea (Israel). In particular, a Halobacillus sp. DS2, a strain presenting high resistance to NaCl (3–22%), acidic pH (1–4) and cadmium (CdCl 2 MIC: 1,375 mM) was used for QDs biosynthesis studies. Halobacillus sp. synthesize CdS QDs in presence of high NaCl concentrations in a process related with their capacity to generate S 2− in these conditions. Biosynthesized QDs were purified, characterized and their stability at different NaCl concentrations determined. Hexagonal nanoparticles with highly defined structures (hexagonal phase), monodisperse size distribution (2–5 nm) and composed by CdS, NaCl and cysteine were determined by TEM, EDX, HRXPS and FTIR. In addition, QDs biosynthesized by Halobacillus sp. DS2 displayed increased tolerance to NaCl when compared to QDs produced chemically or biosynthesized by non-halophilic bacteria. This is the first report of biological synthesis of salt-stable QDs and confirms the potential of using extremophile microorganisms to produce novel nanoparticles. Obtained results constitute a new alternative to improve QDs properties, and as consequence, to increase their industrial and biomedical applications. © 2019, The Author(s).