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Reversible Self-Assembly of Water-Soluble Gold(I) Complexes

Elisabet Aguiló,  Artur J. Moro, Raquel Gavara, Ignacio Alfonso , Yolanda Pérez , Francesco Zaccaria, Célia Fonseca Guerra, Marc Malfois, Clara Baucells, Montserrat Ferrer, João Carlos Lima , and Laura Rodríguez

Inorg. Chem., 2018, 57 (3), pp 1017–1028

 The reaction of the gold polymers containing bipyridyl and terpyridyl units, [Au(C≡CC15H10N3)]n and [Au(C≡CC10H7N2)]n, with the water-soluble phosphines 1,3,5-triaza-7-phosphatricyclo[3.3.1.13.7]decane and 3,7-diacetyl-1,3,7-triaza-5-phosphabicyclo[3.3.1]nonane gives rise to the formation of four gold(I) alkynyl complexes that self-assemble in water (H2O) and dimethyl sulfoxide (DMSO), through different intermolecular interactions, with an impact on the observed luminescence displayed by the supramolecular assemblies. A detailed analysis carried out by NMR studies performed in different DMSO/deuterated H2O mixtures indicates the presence of two different assembly modes in the aggregates: (i) chain assemblies, which are based mainly on aurophilic interactions, and (ii) stacked assemblies, which are based on Au···π and π···π interactions. These different supramolecular environments can also be detected by their intrinsic optical properties (differences in absorption and emission spectra) and are predicted by the changes in the relative binding energy from density functional theory calculations carried out in DMSO and H2O. Small-angle X-ray scattering (SAXS) experiments performed in the same mixture of solvents are in agreement with the formation of aggregates in all cases. The aromatic units chosen, bipyridine and terpyridine, allow the use of external stimuli to reversibly change the aggregation state of the supramolecular assemblies. Interaction with the Zn2+ cation is observed to disassemble the aggregates, while encapsulating agents competing for Zn2+ complexation revert the process to the aggregation stage, as verified by SAXS and NMR. The adaptive nature of the supramolecular assemblies to the metal-ion content is accompanied by significant changes in the absorption and emission spectra, signaling the aggregation state and also the content on Zn2+.

 

Self-Aggregation and Emulsifying Properties of Methyl Ester Sulfonate Surfactants

Amel Asselah, Aurora Pinazo, Amalia Mezei, Lourdes Pérez and Amel Tazerouti

Journal of Surfactants and Detergents, 2017

Methyl ester sulfonate (MES) anionic surfactants made from natural resources are of particular interest as sustainable surfactants. They offer good physicochemical properties for applications as detergents and emulsifiers. The liquid crystal structures of MES surfactants synthesized in a previous work were determined by polarizing optical microscopy (POM) and small-angle X-ray scattering (SAXS). The emulsifying activity for each surfactant was also measured, and the stability of emulsions was estimated and compared to that induced by sodium dodecyl sulfate (SDS). The POM micrographs showed the presence of birefringent textures. Several factors, including temperature and hydration, influenced the stability of the phases and their structure. SAXS confirmed the structure of the phases formed by dry and hydrated ф-MES surfactants at 25 °C, giving the position of peaks corresponding to the ratio 1:2:3 and revealing the phase transitions of lamellar to double lamellar or the reverse. Also, the Bragg distance (d) decreased with an increase in chain length from 13 to 17 carbon atoms and an increase in the area per molecule of surfactant. The geometric packing parameters were also determined, and suggest that surfactants are tilted. The stability of surfactant emulsions is around 60%, which is comparable to that of SDS. The micrographs show that the emulsions formed are O/W, and an increase in chain length gives rise to a decrease in the size of the emulsion droplets. These results are confirmed by the values of hydrophilic-lipophilic balance (HLB) which reveals the hydrophilic nature of these surfactants.

 

Effect of fatliquoring on leather comfort. Part III: Moisture absorption-desorption of leather

Manich, A.M., Barenys, J., Martinez, L., Lloria, J., Carilla, J. and Marsal, A

Journal of the American Leather Chemists Association,  112, 10, 347-355, 2017

The comfort of tanned hide/skin is an added value, which is decisive for the choice of leather in articles for footwear or clothing, compared to other alternatives whose design excludes this component. This comfort is related to the capacity of absorption and desorption of moisture and with the physical, mechanical and organoleptic characteristics of the leather. After tanning, fatliquoring and retanning are the operations that more intensively modify the characteristics of leather articles. This work is a continuation of two previous ones that have studied the influence of fatliquoring on softness and compressibility of leather and on grain and corium quality of leather assessed by ball bursting and tearing tests. In this case, the effect of fatliquoring on moisture absorption-desorption characteristics of leather is studied. The experimental work has been carried out in the pilot plant of Trumpler Espanola S. A. and the moisture absorption-desorption tests in the Laboratory of Thermal Analysis and Calorimetry of the 1QAC. The behavior of non-fatliquored leather and that of leather fatliquored with a combination of sulphited triglycerides of colza oil and fatty polymer (TCSi/PGR) or fatliquored separately with their components TCSi and PGR, or with phosphoric ester ESF or sulphited fish oil Psi has been determined. The determination of the size of the moisture absorbing monolayer (Xm), the binding energy constants of the monolayer C and the multilayer K, the maximum absorption capacity at saturation XI and the hysteresis (Hyst.) between absorption and desorption, enabled us to classify the different fatliquoring agents according to stage (crust-blue, finished-red) by applying factorial analysis (see following graph). Finishing is the factor that best explains this behavior. Finishing decreases the size of the monolayer and increases the binding energy constants. Fatliquoring decreases the maximum absorption capacity and hysteresis, partially affecting the reduction of the monolayer size.
 

In situ preparation of film and hydrogel bio-nanocomposites of chitosan/fluorescein-copper with catalytic activity

César Saldías, David Díaz Díaz, Sebastián Bonardd, Cristián Soto-Marfull, Alexander Cordoba, Soledad Saldías, Caterina Quezada, Deodato Radic, Ángel Leiva

Carbohydrate Polymers, 180, 15 200-208, 2018

Copper nanoparticles were introduced into chitosan/fluorescein (Ch/f) film and hydrogel matrices by immersion of the respective matrix into an aqueous solution containing the precursor metallic salt and further reduction in aqueous medium at 75 °C for 3 h under nitrogen (N2) atmosphere. TGA was used to estimate the metallic content of Ch/f-Cu film and hydrogel nanocomposites. The prepared nanocomposites were proven to be effective as catalytic materials in the reduction of methylene blue (MB) employing N2H4 as reducing agent. In addition, rate constants of the reduction reaction using Ch/f-Cu film and hydrogel nanocomposites as catalysts were determined. The experimental results showed that the catalytic activity and order of reaction of the MB-N2H4 reduction system depended strongly on the type of nanocomposite used. Finally, the recyclability of the film and hydrogel nanocomposites as catalytic materials was also studied.
 

Adsorption of marine phycotoxin okadaic acid on a covalent organic framework

Laura M. Salonen, Sara R. Pinela, Soraia P.S. Fernandes, João Louçano, Enrique Carbó-Argibay, Marisa P. Sarriá, Carlos Rodríguez-Abreu, João Peixoto and Begoña Espiña

Journal of Chromatography A, 1525, 17-22, 2017

Phycotoxins, compounds produced by some marine microalgal species, can reach high concentrations in the sea when a massive proliferation occurs, the so-called harmful algal bloom. These compounds are especially dangerous to human health when concentrated in the digestive glands of seafood. In order to generate an early warning system to alert for approaching toxic outbreaks, it is very important to improve monitoring methods of phycotoxins in aquatic ecosystems. Solid-phase adsorption toxin tracking devices reported thus far based on polymeric resins have not been able to provide an efficient harmful algal bloom prediction system due to their low adsorption capabilities.

In this work, a water-stable covalent organic framework (COF) was evaluated as adsorbent for the hydrophobic toxin okadaic acid, one of the most relevant marine toxins and the parental compound of the most common group of toxins responsible for the diarrhetic shellfish poisoning. Adsorption kinetics of okadaic acid onto the COF in seawater showed that equilibrium concentration was reached in only 60 min, with a maximum experimental adsorption of 61 mg g-1. Desorption of okadaic acid from the COF was successful with both 70% ethanol and acetonitrile as solvent, and the COF material could be reused with minor losses in adsorption capacity for three cycles. The results demonstrate that COF materials are promising candidates for solid-phase adsorption in water monitoring devices.
 

Design of parenteral MNP-loaded PLGA nanoparticles by a low-energy emulsification approach as theragnostic platforms for intravenous or intratumoral administration

G. Calderó, C. Fornaguera, L. Zadoina, A. Dols-Perez and C.Solans

Colloids and Surfaces B: Biointerfaces, 160, 535-542, 2017

Encapsulation of magnetic nanoparticles (MNP) into PLGA nanoparticles has been achieved by nano-emulsion templating using for the first time both, a low-energy emulsification method as well as biocompatible components accepted for pharmaceuticals intended for human use. The incorporation of MNP by nano-emulsion templating method proposed in this work has been investigated in two different systems applying mild process conditions and is shown to be simple and versatile, providing stable MNP-loaded PLGA nanoparticles with tunable size and MNP concentration. MNP-loaded PLGA nanoparticles showed sizes below 200 nm by DLS and 50 nm by TEM, and mean MNP loading per PLGA nanoparticle of 1 to 4, depending on the nanoparticle dispersion composition. Physical-chemical features suggest that the MNP-loaded PLGA nanoparticles obtained are good candidates for intravenous or intratumoral administration.
 

Relevance of the DFT method to study expanded porphyrins with different topologies

Torrent-Sucarrat M., Navarro S., Cossío F.P., Anglada, J.M. and Luis, J.M

Journal of Computational Chemistry, 2017

Meso-aryl expanded porphyrins present a structural versatility that allows them to achieve different topologies with distinct aromaticities. Several studies appeared in the literature studying these topological switches from an experimental and theoretical point of view. Most of these publications include density functional theory calculations, being the B3LYP the most used methodology. In this work, we show that the selection of the functional has a critical role on the geometric, energetic, and magnetic results of these expanded porphyrins, and that the use of an inadequate methodology can even generate spurious stationary points on the potential energy surface. To illustrate these aspects, in this article we have studied different molecular distortions of two expanded porphyrins, [32]-heptaphyrin and [26]-hexaphyrin using 11 DFT functionals and performing single point energy calculations at the local pair natural orbital coupled cluster DLPNO-CCSD(T) method, which have been carried out for benchmarking purposes. For some selected functionals, the dispersion effects have also been evaluated using the D3-Grimme's dispersion correction with Becke–Johnson damping. Our results let us to conclude that the CAM-B3LYP, M05-2X, and M06-2X functionals are the methodologies that provide a more consistent description of these topological switches, while other methods, such as B3LYP, BPE, and BP86, show a biased description.
 

On the encapsulation and viability of probiotic bacteria in edible carboxymethyl cellulose-gelatin water-in-water emulsions

Poonam Singh, Bruno Medronho, Maria G. Miguel and Jordi Esquena

Food Hydrocolloids, 2017

In this study, novel biobased dispersions to entrap probiotic bacteria were developed and characterized regarding their formation, microstructure and in vitro viability and culturability performance in model salivary, gastric and intestinal fluids. The systems are composed of type B pigskin gelatin and sodium carboxymethyl cellulose (NaCMC) which, depending on concentrations and temperature, can form water-in-water (W/W) emulsion droplets as observed by optical and fluorescence microscopy. Model probiotic bacteria, Lactobacillus rhamnosus GG (LGG), were successfully entrapped into the W/W emulsion droplets with surprisingly high viability. Moreover, the survival of the LGG cells, when exposed to the different model fluids, was improved after their entrapment in the W/W emulsions. Therefore, the developed dispersions display high potential for probiotic encapsulation and eventual delivery into the intestinal tract with acceptable viability.
 

Sandwich NP-based biobarcode assay for quantification C-reactive protein in plasma samples

Marta Brotoa, Roger Galve and M.-Pilar Marco

Analytica Chimica Acta 2017

A NP-based biobarcode for C-reactive protein (CRP) quantification in plasma samples is reported for the first time. The assay uses capture antibody functionalized magnetic beads (pAbCRP2-MP), multifunctional oligonucleotide encoded probes modified with a detection antibody (pAbCRP1-ePSP), and a fluorescent DNA microarray. Thus, magnetic beads are added to the sample to form immunocomplexes that will be isolated, to then add the codified particles to form a sandwich complex with both particles and the target protein, subsequently the complexes are treated to release the oligonucleotide codes, which are finally hybridized in a fluorescent DNA microarray. The assay has been implemented to the analysis of plasma samples being able to quantify this biomarker within 900 ng mL-1 to 12500 ng mL-1 with an excellent accuracy (mean of recovery of 99.5 ± 4.2%, N = 3). The CRP biobarcode has been used on a small pilot clinical study in which plasma samples from patients suffering different pathologies, most of them related to cardiovascular diseases (CVDs). The samples have been analyzed and the results compared to a reference method demonstrating that the assay can be useful for monitoring this biomarker on patients being suspicious to be under risk of suffering CVDs or other diseases involving inflammatory processes.
 

Cytotoxic effects of commonly used nanomaterials and microplastics on cerebral and epithelial human cells

Gabriella F. Schirinzi, Ignacio Pérez-Pomeda, Josep Sanchís, Cesare Rossini, Marinella Farré, Damià Barceló

Environmental Research 159 (2017) 579–587

Plastic wastes are among the major inputs of detritus into aquatic ecosystems. Also, during recent years the increasing use of new materials such as nanomaterials (NMs) in industrial and household applications has contributed to the complexity of waste mixtures in aquatic systems. The current effects and the synergism and antagonisms of mixtures of microplastics (MPLs), NMs and organic compounds on the environment and in human health have, to date, not been well understood but instead they are a cause for general concern.

The aim of this work is to contribute to a better understanding of the cytotoxicity of NMs and microplastics/nanoplastics (MPLs/NPLs), at cell level in terms of oxidative stress (evaluating Reactive Oxygen Species effect) and cell viability. Firstly, the individual cytotoxicity of metal nanoparticles (NPs) (AgNPs and AuNPs), of metal oxide NPs (ZrO2NPs, CeO2NPs, TiO2NPs, and Al2O3NPs), carbon nanomaterials (C60fullerene, graphene), and MPLs of polyethylene (PE) and polystyrene (PS) has been evaluated in vitro. Two different cellular lines T98G and HeLa, cerebral and epithelial human cells, respectively, were employed. The cells were exposed during 24–48 h to different levels of contaminants, from 10 ng/mL to 10 µg/mL, under the same conditions. Secondly, the synergistic and antagonistic relationships between fullerenes and other organic contaminants, including an organophosphate insecticide (malathion), a surfactant (sodium dodecylbenzenesulfonate) and a plasticiser (diethyl phthalate) were assessed. The obtained results confirm that oxidative stress is one of the mechanisms of cytotoxicity at cell level, as has been observed for both cell lines and contributes to the current knowledge of the effects of NMs and MPLs-NPLs.
 


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