Synergistic Antifungal Study of PEGylated Graphene Oxides and Copper Nanoparticles against Candida albicans

© 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).The coupling reactions of polyethylene glycol (PEG) with two different nano-carbonaceous materials, graphene oxide (GO) and expanded graphene oxide (EGO), were achieved by amide bond formations. These reactions yielded PEGylated graphene oxides, GO-PEG and EGO-PEG. Whilst presence of the newly formed amide links (NH-CO) were confirmed by FTIR stretches observed at 1732 cm−1 and 1712 cm−1, the associated Raman D- and G-bands resonated at 1311/1318 cm−1 and 1584/1595 cm−1 had shown the carbonaceous structures in both PEGylated products remain unchanged. Whilst SEM images revealed the nano-sheet structures in all the GO derivatives (GO/EGO and GO-PEG/EGO-PEG), TEM images clearly showed the nano-structures of both GO-PEG and EGO-PEG had undergone significant morphological changes from their starting materials after the PEGylated processes. The successful PEGylations were also indicated by the change of pH values measured in the starting GO/EGO (pH 2.6–3.3) and the PEGylated GO-PEG/EGO-PEG (pH 6.6–6.9) products. Initial antifungal activities of selective metallic nanomaterials (ZnO and Cu) and the four GO derivatives were screened against Candida albicans using the in vitro cut-well method. Whilst the haemocytometer count indicated GO-PEG and copper nanoparticles (CuNPs) exhibited the best antifungal effects, the corresponding SEM images showed C. albicans had, respectively, undergone extensive shrinkage and porosity deformations. Synergistic antifungal effects all GO derivatives in various ratio of CuNPs combinations were determined by assessing C. albicans viabilities using broth dilution assays. The best synergistic effects were observed when a 30:70 ratio of GO/GO-PEG combined with CuNPs, where MIC50 185–225 μm/mL were recorded. Moreover, the decreased antifungal activities observed in EGO and EGO-PEG may be explained by their poor colloidal stability with increasing nanoparticle concentrations.Peer reviewe

Propiedades de flujo de suspensiones lateríticas concentradas: influencia de la mineralogía y de las características coloidales

Tesis doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Química Agrícola, Geología y Geoquímica. Fecha de lectura: 25-4-199

Propiedades de flujo de suspensiones lateriticas concentradas Influencia de la mineralogia y de las caracteristicas coloidales

Centro de Informacion y Documentacion Cientifica (CINDOC). C/Joaquin Costa, 22. 28002 Madrid. SPAIN / CINDOC - Centro de Informaciòn y Documentaciòn CientìficaSIGLEESSpai

Impacto del sistema de evaluación de conocimientos y competencias en la enseñanza semipresencial en los Cursos de Adaptación a Grado en Ingeniería Mecánica y Eléctrica

SIN FINANCIACIÓNNo data 201

Coarse-Grained Molecular Dynamics of pH-Sensitive Lipids

pH-sensitive lipids represent a class of lipids that can be protonated and destabilized in acidic environments, as they become positively charged in response to low-pH conditions. They can be incorporated into lipidic nanoparticles such as liposomes, which are able to change their properties and allow specific drug delivery at the acidic conditions encountered in some pathological microenvironments. In this work, we used coarse-grained molecular-dynamic simulations to study the stability of neutral and charged lipid bilayers containing POPC (1-palmitoyl-2-oleoyl-sn-glycero-3- phosphocholine) and various kinds of ISUCA ((F)2-(imidazol-1-yl)succinic acid)-derived lipids, which can act as pH-sensitive molecules. In order to explore such systems, we used a MARTINIderived forcefield, previously parameterized using all-atom simulation results. We calculated the average area per lipid, the second-rank order parameter and the lipid diffusion coefficient of both lipid bilayers made of pure components and mixtures of lipids in different proportions, under neutral or acidic conditions. The results show that the use of ISUCA-derived lipids disturbs the lipid bilayer structure, with the effect being particularly marked under acidic conditions. Although morein depth studies on these systems must be carried out, these initial results are encouraging and the lipids designed in this research could be a good basis for developing new pH-sensitive liposomes.Sin financiación6.208 Q1 JCR 20211.176 Q1 SJR 2021No data IDR 2021UE

Modelización molecular de la adsorción de proteínas y surfactantes iónicos sobre nanotubos de carbono

En este trabajo se estudian las interacciones que se establecen entre distintas moléculas de interés en aplicaciones biomédicas, en concreto la albúmina de suero fetal bovino (BSA) y los surfactantes dodecil sulfato de sodio (SDS) y dodecil bencen sulfonato de sodio (SDBS), con un nanotubo de carbono (CNT) mediante métodos computacionales de dinámica molecular. La adsorción de las dichas moléculas sobre la superficie del CNT se analiza siguiendo la evolución temporal de las distancias intermoleculares, así como calculando la energía de interacción molécula-CNT.UEM2014No data 2018UE

Optimización del conformado de una superaleación experimental

Sin financiaciónNo data 2018UE

Nickel(II) removal by mixtures of Acorga M5640 and DP8R in pseudo-emulsion based hollow fiber with strip dispersion technology

This work presents the investigation of Ni(II) extraction from aqueous solution through pseudo-emulsion based hollow fiber strip dispersion (PSEHFSD) containing the mixture 2-hydroxy-5-nonylbenzaldehyde oxime+di(2-ethylhexyl) phosphoric acid/Exxsol D100 as extractant in the form of a pseudo-emulsion with H₂SO₄. The organic and aqueous strip phases are separated when the stirring device is stopped. The permeation of Ni(II) is investigated as a function of various experimental variables: hydrodynamic conditions, feed pH, extractants mixture concentration in the pseudo-emulsion, initial Ni(II) concentration in feed phase, H₂SO₄ concentration in the pseudo-emulsion as strippant. In PEHFSD, pseudo-emulsion is an emulsion that is formed temporarily between organic and stripping solutions. In this investigation, feed was circulated through the lumen side in counter-current mode. The selectivity of 2-hydroxy-5-nonylbenzaldehyde oxime+di(2-ethylhexyl) phosphoric acid/Exxsol D100 based PEHFSD toward different metals was also examined.3.155 JCR (2010) Q1, 28/193 Environmental sciencesUE

Nanocompuestos de óxido de manganeso soportados en estructuras nanocarbonadas y en presencia de líquidos iónicos

Se ha llevado a cabo la síntesis de óxido de manganeso a partir de KMnO4 soportado sobre nanoplaquetas de óxido de grafeno sin adición y con adición de líquidos iónicos (LI), habiéndose utilizado los siguientes tipos de LI: 1) Cloruro de 1-etil-3-metilimidazolio,2) cloruro de 1-decil-3-metilimidazolio, 3) cloruro de 1-bencil-3-metilimidazolio en diferentes concentraciones. Posteriormente, se ha procedido a la caracterización estructural mediante microscopía de barrido (SEM) y transmisión (TEM) y la correspondiente correlación de las características fisicoquímicas de las nanopartículas obtenidas con las condiciones de síntesis. En el estudio de la estabilidad coloidal se observan diferencias en los valores de los puntos isoeléctricos cuando se utilizan LI a baja y alta concentración en comparación a cuando no hay presencia de éstos. La adición de LI desplaza el punto isoeléctrico hacia pH más básicos. En todos los casos estudiados por encima de pH= 6 predomina la carga negativa con valores de potencial zeta comprendidos entre -20 y - 50 mV. Por debajo de pH=6 los valores máximos de potencial zeta que se obtienen son de 30 mV.MAT2015-67586-CR-2-R (MINECO/FEDER)2016/UEM17No data (2017)UE

Amino-Functionalized Multiwall Carbon Nanotubes as Efficient Basic Catalysts for the Formation of γ-Lactams: Synthesis of N-1-Heptenyl-2-pyrrolidinone

In this work, we prepared a series of N-functionalized carbon nanotubes by means of a process of acylation-amidation of commercial multiwall carbon nanotubes that were previously pre-oxidized with nitric acid. Three different amines, butylamine, N,N-dimethyl ethylenediamine, and ethylenediamine, were used in the process. The characterization of samples by several techniques probed the incorporation of nitrogen atoms to the carbon nanotubes, especially in the case of ethylenediamine. The solids were tested as catalysts in the synthesis of N-1-heptenyl-2-pyrrolidinone, included in the group of a γ-lactams, compounds that show important biological properties. The most active catalyst was that prepared with butylamine, which exhibited the highest SBET and Vpore values and contained an amount of nitrogen that was intermediate between that of the other two catalysts. A yield of 60% to N-1-heptenyl-2-pyrrolidinone was achieved after 3 h at 120 °C under free-solvent conditions. This catalyst could be used in four consecutive cycles without significant activity loss