Browsing by Author "Araya-Duran, Ingrid"

Now showing 1 - 3 of 3
  • No Thumbnail Available
    Item
    A first-principles study on the adsorption properties of phosphorene oxide for pollutant removal from water
    (2022) Cortes-Arriagada, Diego; Barria, Natacha; Ortega, Daniela E.; Araya-Duran, Ingrid; Camarada, Maria Belen
    Phosphorene-based materials have emerged as useful platforms for new technological applications, including their potential implementation in the solid-phase extraction of pollutants. In this study, we implemented a first-principles study to characterize the interactions between water-soluble pollutants and phosphorene oxide (PhosO) at the microscopic level, providing useful mechanistic insights into the role of phosphorene oxidation in its adsorption/removal ability. Continuum/explicit solvent effects were considered to explain the solvent role, and the ALMO-EDA method characterizes the intermolecular forces. Our results show that PhosO significantly adsorbs pollutants on its surface by inner surface adsorption, even under aqueous environments, and provides remarkable adsorption stability for a wide family of water-soluble emerging contaminants (pharmaceuticals, endocrine disruptors, flame retardants, and industrial chemicals) with adsorption energies of 0.53 to 1.17 eV. The stabilizing energy in solution is driven by a balanced contribution of dispersion and electrostatic driving forces (up to 83% of the stabilizing energy), overcompensating all the destabilizing effects from the solvation process and Pauli repulsion. Furthermore, PhosO promotes low pollutant mobility from its surface under water molecules, which are not competitive factors in the adsorption process. In addition, simulations under dynamic conditions show that the electrostatic/dispersion governed mechanism remains stable at room conditions for real-life applications (300 K, 1 atm). Finally, a bandgap increase of 0.73 eV is noted in PhosO upon pollutant adsorption, giving a suitable framework for further sensing applications of contaminants by increasing the metallic character of PhosO. These results expand the understanding of the role of phosphorene oxidation for its use as a removal platform in water treatment technologies. (c) 2022 Elsevier B.V. All rights reserved.
  • No Thumbnail Available
    Item
    Conformational Changes of Poly(Maleic Anhydride-alt-styrene) Modified with Amino Acids in an Aqueous Medium and Their Effect on Cytocompatibility and Hemolytic Response
    (2023) Maine, Arianne; Tamayo, Laura; Leiva, Angel; Gonzalez, Alex; Rios, Hernan E.; Rojas-Romo, Carlos; Jara, Paul; Araya-Duran, Ingrid; Gonzalez-Nilo, Fernando; Yazdani-Pedram, Mehrdad; Santana, Paula; Leal, Matias; Gonzalez, Nicolas; Briones, Ximena; Villalobos, Valeria; Urzua, Marcela
    The conformational changes of poly-(maleic anhydride-alt-styrene) (PSMA) modified with different amino acids (PSMA-Aa) were studied in an aqueous medium as a function of ionic strength and pH. The specific viscosity of PSMA-Aa decreased with increasing salt concentration due to a more compact conformation. There was a decrease in surface tension with increasing concentrations of the modified polyelectrolyte having a greater effect for the PSMA modified with l-phenylalanine at pH 7.0, demonstrating a greater surface-active character. The conformational changes were also confirmed by molecular dynamics studies, indicating that PSMA-Aa exhibits a compact structure at pH 4.0 and a more extended structure at pH 7.0. On the other hand, the conformational changes of PSMA-Aa were related to its biological response, where the higher surface-active character of the PSMA modified with l-phenylalanine correlates very well with the higher hemolytic activity observed in red blood cells, in which the surface-active capacity supports lytic potency in erythrocytes. The cytocompatibility assays indicated that there were no significant cytotoxic effects of the PSMA-Aa. Additionally, in solvent-accessible surface area studies, it was shown that the carboxylate groups of the PSMA modified with l-phenylalanine are more exposed to the solvent at pH 7.0 and high salt concentrations, which correlates with lower fluorescence intensity, reflecting a loss of mitochondrial membrane potential. It is concluded that the study of the conformational changes in PE modified with amino acids is essential for their use as biomaterials and relevant to understanding the possible effects of PE modified with amino acids in biological systems.
  • No Thumbnail Available
    Item
    New Hybrid Copper Nanoparticles/Conjugated Polyelectrolyte Composite with Antibacterial Activity
    (2021) Jessop, Ignacio A.; Perez, Yasmin P.; Jachura, Andrea; Nunez, Hipolito; Saldias, Cesar; Isaacs, Mauricio; Tundidor-Camba, Alain; Terraza, Claudio A.; Araya-Duran, Ingrid; Camarada, Maria B.; Carcamo-Vega, Jose J.
    In the search for new materials to fight against antibiotic-resistant bacteria, a hybrid composite from metallic copper nanoparticles (CuNPs) and a novel cationic pi-conjugated polyelectrolyte (CPE) were designed, synthesized, and characterized. The CuNPs were prepared by chemical reduction in the presence of CPE, which acts as a stabilizing agent. Spectroscopic analysis and electron microscopy showed the distinctive band of the metallic CuNP surface plasmon and their random distribution on the CPE laminar surface, respectively. Theoretical calculations on CuNP/CPE deposits suggest that the interaction between both materials occurs through polyelectrolyte side chains, with a small contribution of its backbone electron density. The CuNP/CPE composite showed antibacterial activity against Gram-positive (Staphylococcus aureus and Enterococcus faecalis) and Gram-negative (Escherichia coli and Salmonella enteritidis) bacteria, mainly attributed to the CuNPs' effect and, to a lesser extent, to the cationic CPE.