Examinando por Autor "Araya, E."

Mostrando 1 - 3 de 3
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    Ítem
    Encapsulation of gold nanostructures and oil-in-water nanocarriers in microgels with biomedical potential
    (MDPI AG, 2018) Inostroza-Riquelme, M.; Vivanco, A.; Lara, P.; Guerrero, S.; Salas-Huenuleo, E.; Chamorro, A.; Leyton, L.; Bolaños, K.; Araya, E.; Quest, A.F.G.; Kogan, M.J.; Oyarzun-Ampuero, F.
    Here we report the incorporation of gold nanostructures (nanospheres or nanorods, functionalized with carboxylate-end PEG) and curcumin oil-in-water (O/W) nanoemulsions (CurNem) into alginate microgels using the dripping technique. While gold nanostructures are promising nanomaterials for photothermal therapy applications, CurNem possess important pharmacological activities as reported here. In this sense, we evaluated the effect of CurNem on cell viability of both cancerous and non-cancerous cell lines (AGS and HEK293T, respectively), demonstrating preferential toxicity in cancer cells and safety for the non-cancerous cells. After incorporating gold nanostructures and CurNem together into the microgels, microstructures with diameters of 220 and 540 µm were obtained. When stimulating microgels with a laser, the plasmon effect promoted a significant rise in the temperature of the medium; the temperature increase was higher for those containing gold nanorods (11–12 ◦ C) than nanospheres (1–2 ◦ C). Interestingly, the incorporation of both nanosystems in the microgels maintains the photothermal properties of the gold nanostructures unmodified and retains with high efficiency the curcumin nanocarriers. We conclude that these results will be of interest to design hydrogel formulations with therapeutic applications. © 2018 by the authors.
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    Improving cell penetration of gold nanorods by using an amphipathic arginine rich peptide
    (Dove Medical Press Ltd., 2020) Riveros, A.; Eggeling, C.; Riquelme, S.; Adura, C.; López-Iglesias, C.; Guzmán, F.; Araya, E.; Almada, M.; Juárez, J.; Valdez, M.; Fuentevilla, I.; López, O.
    Gold nanorods are highly reactive, have a large surface-to-volume ratio, and can be functionalized with biomolecules. Gold nanorods can absorb infrared electromagnetic radiation, which is subsequently dispersed as local heat. Gold nanoparticles can be used as powerful tools for the diagnosis and therapy of different diseases. To improve the biological barrier permeation of nanoparticles with low cytotoxicity, in this study, we conjugated gold nanorods with cell-penetrating peptides (oligoarginines) and with the amphipathic peptide CLPFFD. Methods: We studied the interaction of the functionalized gold nanorods with biological membrane models (liposomes) by dynamic light scattering, transmission electron microscopy and the Langmuir balance. Furthermore, we evaluated the effects on cell viability and permeability with an MTS assay and TEM. Results and Discussion: The interaction study by DLS, the Langmuir balance and cryo-TEM support that GNR-Arg7 CLPFFD enhances the interactions between GNRs and biological membranes. In addition, cells treated with GNR-Arg7 CLPFFD internalized 80% more nanoparticles than cells treated with GNR alone and did not induce cell damage. Conclusion: Our results indicate that incorporation of an amphipathic sequence into oligoarginines for the functionalization of gold nanorods enhances biological membrane nanoparticle interactions and nanoparticle cell permeability with respect to nanorods functionalized with oligoarginine. Overall, functionalized gold nanorods with amphipathic arginine rich peptides might be candidates for improving drug delivery by facilitating biological barrier permeation.
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    Physicochemical and Theoretical Characterization of a New Small Non-Metal Schiff Base with a Differential Antimicrobial Effect against Gram-Positive Bacteria
    (MDPI, 2022-01) Gacitúa, M.; Carreño, A.; Morales-Guevara, R.; Páez-Hernández, D.; Martínez-Araya, J.; Araya, E.; Preite, M.; Otero, C.; Rivera-Zaldívar, M.; Silva, A.; Fuentes, J.
    Searching for adequate and effective compounds displaying antimicrobial activities, especially against Gram-positive bacteria, is an important research area due to the high hospitalization and mortality rates of these bacterial infections in both the human and veterinary fields. In this work, we explored (E)-4-amino-3-((3,5-di-tert-butyl-2-hydroxybenzylidene)amino) benzoic acid (SB-1, harboring an intramolecular hydrogen bond) and (E)-2-((4-nitrobenzilidene)amino)aniline (SB-2), two Schiff bases derivatives. Results demonstrated that SB-1 showed an antibacterial activity determined by the minimal inhibitory concentration (MIC) against Staphylococcus aureus, Enterococcus faecalis, and Bacillus cereus (Gram-positive bacteria involved in human and animal diseases such as skin infections, pneumonia, diarrheal syndrome, and urinary tract infections, among others), which was similar to that shown by the classical antibiotic chloramphenicol. By contrast, this compound showed no effect against Gram-negative bacteria (Klebsiella pneumoniae, Escherichia coli, and Salmonella enterica). Furthermore, we provide a comprehensive physicochemical and theoretical characterization of SB-1 (as well as several analyses for SB-2), including elemental analysis, ESMS,1H and13C NMR (assigned by 1D and 2D techniques), DEPT, UV-Vis, FTIR, and cyclic voltammetry. We also performed a computational study through the DFT theory level, including geometry optimization, TD-DFT, NBO, and global and local reactivity analyses. © 2022 by the authors. Licensee MDPI, Basel, Switzerland.