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PENETRATION OF POLYMERIC NANOPARTICLES LOADED WITH AN HIV-1 INHIBITOR PEPTIDE DERIVED FROM GB VIRUS C IN A VAGINAL MUCOSA MODEL

Ariza-Sáenz Martha, Espina Marta, Bolaños Nuria , Calpena Ana Cristina, Gomara María José, Haro Isabel and García María Luisa

European Journal of Pharmaceutics and Biopharmaceutics 2017

Despite the great effort to decrease the HIV infectivity rate, current antiretroviral therapy has several weaknesses; poor bioavailability, development of drug resistance and poor ability to access tissues. However, molecules such as peptides have emerged as a new expectative to HIV eradication. The vaginal mucosa is the main spreading point of HIV. There are natural barriers such as the vaginal fluid which protects the vaginal epithelium from any foreign agents reaching it. This present work has developed and characterized Nanoparticles (NPs) coated with glycol chitosan (GC), loaded with an HIV-1 inhibitor peptide (E2). In vitro release and ex vivo studies were carried out using the vaginal mucosa of swine and the peptide was determined by HPLC MS/MS validated method. Moreover, the peptide was labeled with 5(6)-carboxyfluoresceine and entrapped into the NPs to carried out in vivo studies and to evaluate the NPs penetration and toxicity in the vaginal mucosa of the swine. The mean size of the NPs, ξ and the loading percentage were fundamental features for to reach the vaginal tissue and to release the peptide within intercellular space. The obtained results suggesting that the fusion inhibitor peptides loaded into the NPs coated with GC might be a new way to fight the HIV-1, due to the formulation might reach the human epithelial mucosa and release peptide without any side effects.

 

Paradigm shift for preparing versatile M2+-free gels from unmodified sodium alginate

Pérez-Madrigal, M.; Torras, J.; Casanovas, J.; Häring, M.; Aleman, C.; Díaz, D. D.

Biomacromolecules 2017

This manuscript describes a new route to prepare rapidly Ca2+-free hydrogels from unmodified sodium alginate by simply mixing with small organic molecules such as poly(carboxylic acid) compounds as cross-linker agents instead of classical divalent metal salts such as CaCl2. Dimethyl sulfoxide (DMSO) was also found to induce the rapid gelation of aqueous alginate solutions. The gelation process takes place at room temperature, and depending on the composition, gels with good thermal (90–100 °C) and mechanical properties compared to classical metal-containing analogs are obtained. DMSO-based gels showed remarkable self-supporting and thixotropic properties, which can be tuned by the biopolymer concentration. Furthermore, oxalic acid-based gels show superior elasticity than HCl, CaCl2 and DMSO-based gels. The possibility to prepare monoliths, beads, and films of these gels provide them with significant versatility. In particular, films made of alginate and oxalic acid show good potential as synergistic anticancer drug delivery carrier. Computational studies using both quantum mechanical and classical force-field methodologies reveal that hydrogen bonding networks between water and DMSO molecules located close to the alginate chains are responsible for the stability of DMSO-based gels. In contrast, the cohesion of oxalic acid-based gels is a consequence of the coexistence of multiple ionic associations involving oxalate, alginate, and Na+ counterions, which stabilize the system and keep all the interacting species grouped.
 

Ultrasonication-enhanced gelation properties of a versatile amphiphilic formamidine-based gelator exhibiting both organogelation and hydrogelation abilities

Bachl, J.; Sampedro, D.; Mayr, J.; Díaz, D. D.

Phys. Chem. Chem. Phys. 2017, 19, 22981-22994

We describe the preparation of a novel amphiphilic gelator built from a formamidine core, which is able to form a variety of physical organogels and hydrogels at concentrations ranging from 15 to 150 mg mL−1. Interestingly, ultrasound treatment of isotropic solutions (i.e., gel-precursor) resulted in a remarkable enhancement of the gelation kinetics as well as the gelation scope and characteristic gel properties (e.g., critical gelation concentration, gel-to-sol transition temperature, viscoelastic moduli) in comparison to the heating–cooling protocol typically used to obtain supramolecular gels. Thermoreversibility, thixotropy, injectability and multistimuli responsiveness are some of the most relevant functionalities of these gels. Electron microscopy imaging revealed the formation of entangled networks made of fibers of nanometer diameters and micrometer lengths, with different morphological features depending on the solvent. Insights into the driving forces for molecular aggregations were obtained from FTIR, NMR, PXRD and computational studies. The results suggest a major stabilization of the fibers through additive N–H⋯O hydrogen bonds, in combination with hydrophobic interactions, over π–π stacking interactions.
 

What Controls Photocatalytic Water Oxidation on Rutile TiO2(110) under Ultra-High-Vacuum Conditions?

Annapaola Migani and Lluís Blancafort

J. Am. Chem. Soc., 2017, 139 (34), pp 11845–11856

The photocatalytic O–H dissociation of water absorbed on a rutile TiO2(110) surface in ultrahigh vacuum (UHV) is studied with spin-polarized density functional theory and a hybrid exchange-correlation functional (HSE06), treating the excited-state species as excitons with triplet multiplicity. This system is a model for the photocatalytic oxidation of water by TiO2 in an aqueous medium, which is relevant for the oxygen evolution reaction and photodegradation of organic pollutants. We provide a comprehensive mechanistic picture where the most representative paths correspond to excitonic configurations with the hole located on three- and two-coordinate surface oxygen atoms (O3s and O2s). Our picture explains the formation of the species observed experimentally. At near band gap excitation, the O3s path leads to the generation of hydroxyl anions which diffuse on the surface, without net oxidation. In contrast, free hydroxyl radicals are formed at supra band gap excitation (e.g., 266 nm) from an interfacial exciton that undergoes O–H dissociation. The oxidation efficiency is low because the path associated with the O2s exciton, which is the most favored one thermodynamically, is unreactive because of a high propensity for charge recombination. Our results are also relevant to understand the reactivity in the liquid phase. We assign the photoluminescence measured for atomically flat TiO2(110) surfaces in an aqueous medium to the O3s exciton, in line with the proposal based on experiments, and we have identified a species derived from the O2s exciton with an activated O2s–Ti bond that may be relevant in photocatalytic applications in an aqueous medium.
 

Microvesicle release and micellar attack as the alternative mechanisms involved in the red-blood-cell-membrane solubilization induced by arginine-based surfactants

M. Elisa Fait, Melisa Hermet, Francesc Comelles, Pere Clapés, H. Ariel Alvarez, Eduardo Prieto, Vanesa Herlax, Susana R. Morcelle  and  Laura Bakás

RSC Advances,7, 60, 37549-37558, 2017

Two novel arginine-based surfactants, Bz-Arg-NHC10 and Bz-Arg-NHC12, were characterized with respect to surface properties and their interaction with human red-blood-cell (HRBC) membranes. The values for critical micellar concentration (CMC), the maximum surfactant adsorption at the air–liquid interface, and the area per molecule indicated better surface properties for Bz-Arg-NHC12. The observation of cylindrical worm-like aggregates of Bz-Arg-NHCn via atomic-force microscopy supported the predictions based on the value of the surfactant-packing parameter (SPP). Erythrocyte-membrane solubilization was effected by surfactant aggregates since cell lysis became evident at only surfactant concentrations above the CMC. Changes in HRBC shape observed at different surfactant concentrations led to the conclusion that a slow mechanism based on the insertion of surfactant monomers into the HRBC membrane, followed by a shedding of microvesicles was responsible for the hemolysis produced by both surfactants at the lower concentrations tested. In contrast, the extraction of membrane lipids upon collisions between HRBCs and surfactant aggregates competes with and prevents microvesicle release at the higher concentrations assayed.
 

Green synthesis of silver nanoparticles in oil-in-water microemulsion and nano-emulsion using geranium leaf aqueous extract as a reducing agent

Ruben Dario Rivera-Rangel. M. Pilar González-Muñoz. Mario Avila-Rodriguez. .Teresa Alejandra Razo-Lazcano. Conxita Solans

Colloids and Surfaces A: Physicochemical and Engineering Aspects 2017

A green synthesis of silver nanoparticles was developed, using a low-toxic system of microemulsion and nano-emulsion with castor oil as the oily phase, Brij 96 V and 1,2-hexanediol as the surfactant and co-surfactant respectively. Geranium (P. hortorum) leaf aqueous extract was employed as a reducing agent. The content and concentration of a metallic precursor and geranium leaf extract (GLE) in the systems used makes it possible to obtain different sizes of silver nanoparticles from 25 to 150 nm. The characterization by FTIR and Z potential shows that the biomolecules of the plant extract act as a reducing and capping agent, giving negative charges to the nanoparticle surface. The present study represents a contribution to the green synthesis of silver nanoparticles that can be extended to other metals.
 

Comparative study of the diagnostic and prognostic value of antibodies against chimeric citrullinated synthetic peptides and CCP3/CCP3.1 assays

María J. Gómara, Javier Rodríguez, María J. Bleda, Juan P. Salvador, Raimon Sanmartí and Isabel Haro

Clin Chem Lab Med 2017

Background:
The objective of the study was to compare the diagnostic yield of home-made ELISA tests based on synthetic chimeric fibrin/filaggrin citrullinated peptides (CFFCPs) with CCP3 and CCP3.1 commercial tests to detect anti-citrullinated protein/peptide antibodies (ACPAs) in rheumatoid arthritis (RA) patients. The prognostic value is also studied in a cohort of patients with early RA. Moreover, we transfer immunological assays from microtiter plates to microarray formats to allow the simultaneous analysis of several peptide sequences and reduce the volume of serum from patients.
Methods:
The diagnostic study includes: 100 RA patients who fulfilled the 1987 ACR criteria; 100 healthy blood donors; 35 patients with SLE according ACR criteria; 35 patients with PsA fulfilling the Wright and Moll criteria and 30 patients with HCV infection. The prognostic value study includes 50 patients with early RA with follow-up data available. All samples are from outpatients attending the Rheumatology Department of the Hospital Clinic of Barcelona.
Results:
Similar sensitivity, specificity and predictive values for the diagnosis of RA of CCFCPs compared to CCP3/CCP3.1 were obtained. Although a high concordance is observed between anti-CFFCPs and anti-CCP3/CCP3.1 in the early patients that rendered Larsen radiographic progression, CFFCPs could be a better marker of radiographic outcome. Strong correlations between the microarray and ELISA results were found for individual CFFCPs peptides.
Conclusions:
The development of multiplexing techniques combining a different spectrum of markers in a single analysis, including CFFCP peptides, could allow a more detailed analysis of the autoantibodies reactivity found in the sera of patients suffering of this heterogeneous disease.
 

Preparation of a Nanoemulsion with Carapa guianensis Aublet (Meliaceae) Oil by a Low-Energy/Solvent-Free Method and Evaluation of Its Preliminary Residual Larvicidal Activity

Flávia L. M. Jesus, Fernanda B. de Almeida, Jonatas L. Duarte, Anna E. M. F. M. Oliveira, Rodrigo A. S. Cruz, Raimundo N. P. Souto, Ricardo M. A. Ferreira, Regina Gendzelevski Kelmann, José C. T. Carvalho, Ana C. Lira-Guedes, Marcelino Guedes, Conxita Solans and Caio P. Fernandes

Evidence-based Complementary and Alternative Medicine 2017, 6756793, 2017

Andiroba (Carapa guianensis) seeds are the source of an oil with a wide range of biological activities and ethnopharmacological uses. However, few studies have devoted attention to innovative formulations, including nanoemulsions. The present study aimed to obtain a colloidal system with the andiroba oil using a low-energy and organic-solvent-free method. Moreover, the preliminary residual larvicidal activity of the nanoemulsion against Aedes aegypti was evaluated. Oleic and palmitic acids were the major fatty acids, in addition to the phytosterol ß-sitosterol and limonoids (tetranortriterpenoids). The required hydrophile-lipophile was around 11.0 and the optimal nanoemulsion was obtained using polysorbate 85. The particle size distribution suggested the presence of small droplets (mean diameter around 150?nm) and low polydispersity index (around 0.150). The effect of temperature on particle size distribution revealed that no major droplet size increase occurred. The preliminary residual larvicidal assay suggested that the mortality increased as a function of time. The present study allowed achievement of a potential bioactive oil in water nanoemulsion that may be a promising controlled release system. Moreover, the ecofriendly approach involved in the preparation associated with the great bioactive potential of C. guianensis makes this nanoemulsion very promising for valorization of this Amazon raw material.

 

A copper-templated, bifunctional organocatalyst: a strongly cooperative dynamic system for the aldol reaction

Anna Serra-Pont, Ignacio Alfonso, Jordi Solà and  Ciril Jimeno

Org. Biomol. Chem., 15, 6584-6591,2017

The study of novel metal-templated dynamic organocatalytic systems has led to the identification of CuSO4 as the most efficient template to assemble monofunctional prolinamide- and thiourea-modified pyridine ligands. The structural and electronic requirements to assemble an efficient catalyst have been disclosed: both pyridine ligands must bear a 1,3-substitution pattern, and the thiourea ligand serves as a reducing agent to copper(I) as well. Eventually, the cooperative effects achieved with such a simple system deliver high reaction rates and stereoselectivities at room temperature in the asymmetric aldol reaction, requiring only 1 mol% of copper salt.
 

Surface chemistry and germination improvement of Quinoa seeds subjected to plasma activation

A. Gómez-Ramírez, López-Santos, M. Cantos, J. L. García, R. Molina, J. Cotrino, J. P. Espinós & A. R. González-Elipe

Scientific Reports 7, Article number: 5924 (2017)

Plasma treatment is recognized as a suitable technology to improve germination efficiency of numerous seeds. In this work Quinoa seeds have been subjected to air plasma treatments both at atmospheric and low pressure and improvements found in germination rate and percentage of success. Seed water uptake by exposure to water vapor, although slightly greater for plasma treated seeds, did not justify the observed germination improvement. To identify other possible factors contributing to germination, the chemical changes experienced by outer parts of the seed upon plasma exposure have been investigated by X-ray photoemission spectroscopy (XPS) and scanning electron microscopy (SEM-EDX). XPS revealed that the outer layers of the Quinoa plasma treated seeds were highly oxidized and appeared enriched in potassium ions and adsorbed nitrate species. Simultaneously, SEM-EDX showed that the enrichment in potassium and other mineral elements extended to the seed pericarp and closer zones. The disappearance from the surface of both potassium ions and nitrate species upon exposure of the plasma treated seeds to water vapor is proposed as a factor favoring germination. The use of XPS to study chemical changes at seed surfaces induced by plasma treatments is deemed very important to unravel the mechanisms contributing to germination improvement.
 


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