Molecular Modelling of Aromatic Interactions between Pyrene Derivatives and Carbon Nanotubes: Materials for Biomedical Applications

In previous works, we investigated the possibility of using carbon nanotubes functionalized with organic molecules as effective contrast agents for Magnetic Resonance Imaging. This a very useful method for clinical diagnosis, whose effectiveness is conditioned by the development of new contrast agents increasing the quality, resolution, and specificity of the Magnetic Resonance images. Solubilization and functionalization of carbon nanotubes have been previously reported using pyrene derivatives through π–π interactions. In this work, we used dispersion-corrected Density Functional Theory calculations to analyze interactions between carbon nanotubes and several pyrene derivatives. We built two different positions of the aromatic molecule relative to the carbon nanotube (parallel and perpendicular) and calculated binding energies, electrostatic potential surfaces, and electronic charges, in order to shed some light on the interaction strength between both molecules and their preferred orientations. A good interaction between carbon nanotubes and pyrene derivatives is key for the synthesis of materials that work efficiently in biomedical imaging. The results clearly indicate a large influence of the nature of functional groups and orientation of the aromatic molecule relative to the carbon nanotube surface on the adhesion strength.Sin financiación2.400 Q2 JCR 20220.286 Q3 SJR 2022No data IDR 2021UE

Hidrógeno como nuevo vector energético: presente y futuro

La energía está ligada de modo indisoluble a nuestra vida diaria y es necesaria para realizar prácticamente todas las actividades humanas. El ritmo de crecimiento de la población mundial, así como el aumento de la calidad de vida, están dando lugar a una demanda de energía que es cada vez mayor. Sin embargo, hoy en día, más del 80% de toda la energía que se consume procede de combustibles fósiles tales como el petróleo, el gas natural o el carbón. La dependencia excesiva de dichos combustibles se ha convertido en un problema crítico en la economía actual, ya que sus reservas se están agotando y su utilización como fuentes de energía lleva asociados numerosos efectos negativos sobre el medio ambiente. Es imperativa, por lo tanto, la búsqueda de una fuente de energía barata y más sostenible para reemplazar el sistema actual de combustibles fósiles. El hidrógeno, debido a sus propiedades excepcionales, se ha posicionado con fuerza como vector energético del futuro. Este artículo explica los motivos de tal posicionamiento y describe los principales métodos de obtención, almacenamiento y transporte del hidrógeno, así como su aplicación más importante en el sector de la energía: las pilas de combustible.Sin financiaciónNo data 2020UE

Nanotecnología

La nanotecnología es la tecnología de lo extremadamente pequeño, ya que implica la manipulación, creación y aplicación de sistemas a través del control de la materia a escala nanométrica. Se trata de una ciencia que se ha instalado entre nosotros y ha venido para quedarse. El motivo de ello es que la materia, a escala nanométrica, muestra un comportamiento sorprendente y muy diferente al que presenta en su estado masivo. El descubrimiento de nuevas e inesperadas propiedades asociadas a la escala nanométrica ha incentivado la curiosidad científica, abriendo el camino hacia una nueva física y permitiendo el desarrollo de nuevos materiales, así como el de las técnicas necesarias para manipularlos, comprenderlos y aplicarlos: la nanotecnología.Sin financiaciónNo data 2020UE

O interstitial energetics in Ti from ab initio calculations

Ti-porcelain systems have been used in prosthetic dentistry since 1980. The chemical bonding in this kind of systems is generally attributed to oxidic compounds. The porcelain functions as an O donator and stoichiometric and non-stoichiometric titanium oxides are formed at the interface. These oxides result in substantial distortion of the crystalline structure and failure of bonding. A useful technique for surface conditioning is the silicon-ion implantation, which results in the formation of a metal–silicon zone protecting against O diffusion. In dental materials technology, processes on the atomic scale have been investigated insufficiently or not at all. In this work, we present ab initio calculations on the energetics of an O interstitial in a Ti crystal. The aim of our study is getting new insight into the atomic scale properties of these Ti-porcelain systems.Sin financiación1.494 JCR (2005) Q1, 43/178 Material science, multidisciplinaryUE

Interaction between Graphene-Based Materials and Small Ag, Cu, and CuO Clusters: A Molecular Dynamics Study

The excessive use of antibiotics has contributed to the rise in antibiotic-resistant bacteria, and thus, new antibacterial compounds must be developed. Composite materials based on graphene and its derivatives doped with metallic and metallic oxide nanoparticles, particularly Ag, Cu, and Cu oxides, hold great promise. These materials are often modified with polyethylene glycol (PEG) to improve their pharmacokinetic behavior and their solubility in biological media. In this work, we performed molecular dynamics (MD) simulations to study the interaction between small Ag, Cu, and CuO clusters and several graphene-based materials. These materials include pristine graphene (PG) and pristine graphene nanoplatelets (PGN) as well as PEGylated graphene oxide (GO_PEG) and PEGylated graphene oxide nanoplatelets (GO-PEG_N). We calculated the adsorption energies, mean equilibrium distances between the nanoparticles and graphene surfaces, and mean square displacement (MSD) of the nanoclusters. The results show that PEGylation favors the adsorption of the clusters on the graphene surfaces, causing an increase in adsorption energies and a decrease in both distances and MSD values. The strengthening of the interaction could be crucial to obtain effective antibacterial compounds.Universidad Europea de Madrid5.076 JCR (2020) Q1, 35/160 Physics, Applied0.919 SJR (2020) Q1, 49/394 Chemical Engineering (miscellaneous)No data IDR 2019UE

Molecular dynamics simulations of surfactant adsorption on carbon nanotubes intended for biomedical applications

Carbon nanotubes (CNTs) are allotropes of carbon with hollow, long structures, having diameters on the nanometer scale. They can be described as rolled-up graphene layers. During the last years, they have been increasingly used in the fields of pharmacy and biomedicine. However, due to their high hydrophobicity, they cannot be easily handled in most solvents of biological interest. To this end, different surfactants have been used to improve their dispersion in aqueous media. In the present work, we investigated the adsorption behavior of two surfactants, sodium dodecyl sulfate (SDS) and sodium dodecyl benzene sulfonate (SDBS), at different concentrations on a CNT surface by classical molecular dynamics (MD) simulations. Our results are presented in terms of distance between surfactant molecules and CNT surfaces, radial distribution functions and interaction energies. In all the models simulated in this work, a strong interaction of both surfactants with the CNT surface is observed, as it is demonstrated by decreasing distances between the surfactants and the CNT during simulation time, the shape of their radial distribution functions, as well as favorable adsorption processes from an energetic point of view.2014/UEM142.318 JCR (2020) Q3, 116/162 Chemistry, Physical0.406 SJR (2020) 135/394 Chemical Engineering (miscellaneous)No data IDR 2019UE

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

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

Modelling the interaction between graphene surfaces and metallic nanoclusters

The overuse of antibiotics has led to the flourishment of antibiotic-resistant bacteria [1] and consequently to the need to develop new, more efficient pharmacological compounds. Several advanced materials are being studied, among which are metallic nanoparticles and certain graphene oxides (GO) modified with polyethylene glycol (PEG) [2-4]. In this work, molecular dynamics (MD) simulations of the adsorption of small Ag and Cu clusters on pristine graphene and PEGylated graphene oxide (GO_PEG) surfaces were carried out. The results are presented as a function of nanoparticles concentration, adsorption energies, mean equilibrium distances between nanoparticles and graphene surfaces (figure 1), radial distribution functions and diffusion coefficients of the metallic nanoclusters. These preliminary results show that PEGylation of the surface is critical to strengthen the interaction between the surfaces and the metallic clusters, which, in turn, is a key factor for improving the efficacy of these compounds.Sin financiaciónNo data 2020UE

A molecular dynamics modelling adsorption study of Cu and Ag nanoparticles on pristine and functionalized graphene surfaces

The overuse of antibiotics has led to the flourishment of antibiotic-resistant bacteria and consequently to the need to develop new, more efficient pharmacological compounds. It is well known that graphene oxide (GO) doped with metallic particles exhibits broad-spectrum antimicrobial activity. In addition, in order to improve the pharmacokinetic behavior of these compounds and their solubility in biological media, polyethylene glycol (PEG) is attached to the graphene surface. Among the different available characterization techniques, molecular dynamics simulations (MD) deserve special attention, as they allow the study of different materials from a molecular point of view. In this work, MD simulations of the adsorption of small Ag and Cu clusters on pristine graphene and PEGylated graphene oxide (GO_PEG) surfaces were carried out. The results are presented in terms of adsorption energies, mean equilibrium distances between nanoparticles and graphene surfaces, radial distribution functions and diffusion coefficients of the metallic nanoclusters. These preliminary results show that PEGylation of the surface is critical to strengthen the interaction between the surfaces and the metallic clusters, which, in turn, is a key factor for improving the efficacy of these compoundsUEM1915No data JCR 20200.341 SJR (2020) Q3, 306/638 Materials Science (miscellaneous)No data IDR 2019UE