Home Publications

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.

Emulsion-based gels with thermally switchable transparency

Kenji Aramaki, Kazuki Masuda, Ryosuke Horie and Carlos Rodríguez-Abreub

Colloids and Surfaces A: Physicochemical and Engineering Aspects, 533,302-307, 2017

Optical transparency (high light transmittance) of materials is relevant for various applications, and it is of particular interest if it can be switched by stimuli such as temperature. Oil-in-liquid crystal (O/LC) emulsions are a kind of soft materials with excellent workability because of their gel-like and self-standing characteristics. Transparent O/LC emulsions can be obtained by matching the refractive indices of dispersed (oil) and continuous (liquid crystalline) phases. If the refractive indices of the dispersed and continuous phases have different temperature sensitivity, i.e., different thermo-optic coefficients, thermally switchable optical transparency can be realized. In this paper, we report the effect of temperature on the light transmittance of oil-in-cubic phase (O/I1) emulsions in water/poly(oxyethylene) dodecyl ether (C12EO25)/oil systems, with isopropyl hexanoate (IPH) and isopropyl myristate (IPM) as oil components. Transparent emulsions were obtained at 25 °C at surfactant mass fractions in water (WS) of 0.5 for IPH and 0.7 for IPM. The temperature range at which the samples remained transparent was 20–50 °C for the IPH system and 10–70 °C for the IPM system, away from which, the samples were turbid, confirming that the transparency is thermally switchable. We also confirmed the reversibility of switching transparency in the IPH system. Refractive indices of pure oils and the I1 phase were measured at different temperatures. The refractive indices changed linearly with temperature, but the slope (i.e., the thermo-optic coefficient) was different depending on the type of oil, surfactant concentration, and oil solubilization in the I1 phase, which explains the different effect of temperature on the optical transparency of the IPH and IPM systems.

Biobarcode assay for the oral anticoagulant acenocoumarol

Broto, M., Salvador, J.P., Galve, R., Marco, M.P.

Talanta, 178, pp. 308-314, 2018

A novel approach for therapeutic drug monitoring of oral anticoagulants (OA) in clinical samples is reported, based on a NP-based biobarcode assay. The proposed strategy uses specific antibodies for acenocumarol (ACL) covalently bound to magnetic particles (pAb236-MP) and a bioconjugate competitor (hACL-BSA) linked to encoded polystyrene probes (hACL-BSA-ePSP) on a classical competitive immunochemical format. By using this scheme ACL can be detected in low nM range (LOD, 0.96 ± 0.26, N = 3, in buffer) even in complex samples such as serum or plasma (LOD 4 ± 1). The assay shows a high reproducibility (%CV 1.1 day-to-day) and is robust, as it is demonstrated by the fact that ACL can be quantified in complex biological samples with a very good accuracy (slope = 0.97 and R2 = 0.91, of the linear regression obtained when analyzing spiked vs measured values). Moreover, we have demonstrated that the biobarcode approach has the potential to overcome one of the main challenges of the multiplexed diagnostic, which is the possibility to measure in a single run biomarker targets present at different concentration ranges. Thus, it has been proven that the signal and the detectability can be modulated by just modifying the oligonucleotide load of the encoded probes. This fact opens the door for combining in the same assay encoded probes with the necessary oligonucleotide load to achieve the detectability required for each biomarker target.

MicroRNA-200, associated with metastatic breast cancer, promotes traits of mammary luminal progenitor cells

Lourdes Sánchez-Cid, Mònica Pons, Juan José Lozano, Nuria Rubio, Marta Guerra-Rebollo, Aroa Soriano, Laia Paris-Coderch, Miquel F. Segura, Raquel Fueyo, Judit Arguimbau, Erika Zodda, Raquel Bermudo, Immaculada Alonso, Xavier Caparrós, Marta Cascante, Arash Rafii, Yibin Kang, Marian Martínez-Balbás, Stephen J. Weiss, Jerónimo Blanco, Montserrat Muñoz, Pedro L. Fernández and Timothy M. Thomson

Oncotarget. 2017

MicroRNAs are critical regulators of gene networks in normal and abnormal biological processes. Focusing on invasive ductal breast cancer (IDC), we have found dysregulated expression in tumor samples of several microRNAs, including the miR-200 family, along progression from primary tumors to distant metastases, further reflected in higher blood levels of miR-200b and miR-7 in IDC patients with regional or distant metastases relative to patients with primary node-negative tumors. Forced expression of miR-200s in MCF10CA1h mammary cells induced an enhanced epithelial program, aldehyde dehydrogenase (ALDH) activity, mammosphere growth and ability to form branched tubuloalveolar structures while promoting orthotopic tumor growth and lung colonization in vivo. MiR-200s also induced the constitutive activation of the PI3K-Akt signaling through downregulation of PTEN, and the enhanced mammosphere growth and ALDH activity induced in MCF10CA1h cells by miR-200s required the activation of this signaling pathway. Interestingly, the morphology of tumors formed in vivo by cells expressing miR-200s was reminiscent of metaplastic breast cancer (MBC). Indeed, the epithelial components of MBC samples expressed significantly higher levels of miR-200s than their mesenchymal components and displayed a marker profile compatible with luminal progenitor cells. We propose that microRNAs of the miR-200 family promote traits of highly proliferative breast luminal progenitor cells, thereby exacerbating the growth and metastatic properties of transformed mammary epithelial cells.

Page 7 of 94