Examinando por Autor "Arratia-Pérez, R."

Mostrando 1 - 3 de 3
  • Miniatura
    Ítem
    In-situ preparation of CdTe quantum dots capped with a β-cyclodextrin-epichlorohydrin polymer: Polymer influence on the nanocrystal’s optical properties
    (MDPI AG, 2018-11) Martin-Trasanco, R.; Esparza-Ponce, H.E.; Ortiz, P.D.; Oyarzun, D.P.; Zuñiga, C.; Montero-Cabrera, M.E.; Tundidor-Camba, A.; Pizarro, G.C.; Arratia-Pérez, R.
    β-Cyclodextrin (βCD), the less water soluble of the cyclodextrins, has been used as a capping agent in the preparation of semiconductor nanocrystals or quantum dots (QDs). Nevertheless, no reports have been found in the use of the highly water-soluble polymer of this, prepared by the crosslinking of the βCD units with epichlorohydrin in basic medium (βCDP). This polymer, besides to overcome the low solubility of the βCD, increases the inclusion constant of the guest; two parameters that deserve its use as capping agent, instead of the native cyclodextrin. In the present manuscript, we afforded the in-situ aqueous preparation of cadmium telluride (CdTe) QDs capped with βCDP. The polymer influence on the photoluminescent properties of the nanocrystals was analyzed. The βCDP controls the nanocrystals growth during the Oswald ripening stage. Consequently, the CdTe capped βCDP QDs showed lower Stokes-shift values, higher photoluminescent efficiency, and narrower size distribution than for nanocrystals obtained in the absence of polymer. Transmission electron microscopy (TEM) micrographs and energy dispersive X-ray spectroscopy (EDS) analysis revealed the composition and crystallinity of the CdTe QDs. This βCDP capped CdTe QDs is a potential scaffold for the supramolecular modification of QDs surface. © 2018 by the authors.
  • Miniatura
    Ítem
    New properties of a bioinspired pyridine benzimidazole compound as a novel differential staining agent for endoplasmic reticulum and Golgi apparatus in fluorescence live cell imaging
    (Frontiers Media S.A., 2018-08) Llancalahuen, F.M.; Fuentes, J.A.; Carreño, A.; Zúñiga, C.; Páez-Hernández, D.; Gacitúa, M.; Polanco, R.; Preite, M.D.; Arratia-Pérez, R.; Otero, C.
    In this study, we explored new properties of the bioinspired pyridine benzimidazole compound B2 (2,4-di-tert-butyl-6-(3H-imidazo[4,5-c]pyridine-2-yl)phenol) regarding its potential use as a differential biomarker. For that, we performed 1D 1HNMR (TOCSY), UV-Vis absorption spectra in different organic solvents, voltammetry profile (including a scan-rate study), and TD-DFT calculations that including NBO analyses, to provide valuable information about B2 structure and luminescence. In our study, we found that the B2 structure is highly stable, where the presence of an intramolecular hydrogen bond (IHB) seems to have a crucial role in the stability of luminescence, and its emission can be assigned as fluorescence. In fact, we found that the relatively large Stokes Shift observed for B2 (around 175 nm) may be attributed to the stability of the B2 geometry and the strength of its IHB. On the other hand, we determined that B2 is biocompatible by cytotoxicity experiments in HeLa cells, an epithelial cell line. Furthermore, in cellular assays we found that B2 could be internalized by passive diffusion in absence of artificial permeabilization at short incubation times (15 min to 30 min). Fluorescence microscopy studies confirmed that B2 accumulates in the endoplasmic reticulum (ER) and Golgi apparatus, two organelles involved in the secretory pathway. Finally, we determined that B2 exhibited no noticeable blinking or bleaching after 1 h of continuous exposure. Thus, B2 provides a biocompatible, rapid, simple, and efficient way to fluorescently label particular organelles, producing similar results to that obtained with other well-established but more complex methods. © 2018 Llancalahuen, Fuentes, Carreño, Zúñiga, Páez-Hernández, Gacitúa, Polanco, Preite, Arratia-Pérez and Otero.
  • No hay miniatura disponible
    Ítem
    Relativistic-DFT study of the electronic structure, bonding and energetic of the [ref8]- and [uf8]2- ions
    (Chilean Chemical Society., 2013-12) Rabanal-León, W.; Arratia-Pérez, R.
    In this study we evaluated the importance of the relativistic effects (scalar and spin-orbit) on the description of the electronic structure, bonding and the energetic of the [ReF8]- and [UF8]2- ions. We described the bonding interaction between ligands and metal center using the energy decomposition analysis (EDA) proposed by Morokuma and Ziegler, in which it can be appreciated a strong ionic behavior for both ions since the electrostatic interaction energy (?EElestat) is greater than the orbitalic interaction energy (?EOrb). Furthermore, a qualitative analysis using the mapping of the electrostatic potential over the total electronic density evidence an increase of the ionic character, as well as, the polarization of the electronic density as U > Re. The electron localization function (ELF) corroborates the bonding analysis because of the lack of di-synaptic basins on the metal-ligand bonding region.