The design and preparation of highly efficient drug delivery platforms using green methodologies is at the forefront of nanotherapeutics research. POxylated polyurea dendrimers are efficiently synthesized using a supercritical-assisted polymerization in carbon dioxide. These fluorescent, pH-responsive and water-soluble core-shell smart nanocarriers show low toxicity in terms of cell viability and absence of glutathione depletion, two of the major side effect limitations of current vectors. The materials are also found to act as good transfection agents, through a mechanism involving an endosomal pathway, being able to reduce 100-fold the IC50 of paclitaxel.

Functionalized electrospun fibers are of great interest for biomedical applications such as in the design of drug delivery systems. Nevertheless, in some cases the molecules of interest have poor solubility in water or have high melting temperatures. These drawbacks can be overcome using deep eutectic solvents. In this work, poly(vinyl alcohol) (PVA), a common biodegradable biopolymer, was used to produce new functionalized fibers with the eutectic mixture choline chloride:citric acid in a molar ratio of (1:1) ChCl:CA (1:1), which was used as a model system. Fibers were produced from an aqueous solution with 7.8% (w/v) and 9.8% (w/v) of 95% hydrolyzed PVA and a 2% (v/v) of ChCl:CA (1:1). Smooth, uniform fibers with an average diameter of 0.4 μm were obtained with a content of 19.8 wt % of ChCl:CA (1:1) encapsulated.

The power density obtainable by a reverse electrodialysis (RED) stack decreases along its operating period due to fouling; however this effect is not accounted for by the so far proposed mechanistic models. Recently, it has been demonstrated that 2D fluorescence spectroscopy can capture the time evolvement of ion-exchange membrane fouling. In this work multivariate statistical modeling was performed, by using the projection to latent structure (PLS) approach, to predict relevant RED stack performance parameters: pressure drop, stack electric resistance and net power density. Several PLS models, with and without 2D fluorescence data as models inputs, were developed. It was found that inclusion of fluorescence data considerably improved the models fitting, because the otherwise missing information about the dynamic state of ion-exchange membranes was added. Additionally, the coefficients of the optimized models revealed important contributions of some of the input parameters to the predicted outputs and allowed to mathematically confirm the qualitative observations that fouling of anion-exchange membranes facing river water is the main factor affecting the RED stack performance. This work confirms the applicability of 2D fluorescence spectroscopy for monitoring of fouling in RED stacks and demonstrates the ability of simple, statistically based models to follow RED performance.

BACKGROUND The emergence of monoclonal antibodies (mAbs) as new biopharmaceutical products requires the development of new purification methods that are not only effective but are able to reduce production costs. To address the problematic recovery of mAbs, gum arabic (GA) coated magnetic particles (MPs) were used for the purification of human antibodies from animal cells supernatants. RESULTS MPs were synthesized via co-precipitation and exhibited a spherical-like physical aspect, with an average hydrodynamic diameter of 473 nm and a zeta potential of –26 mV. The adsorption and elution of IgG on these adsorbents was thoroughly studied. Adsorption of human IgG was enhanced at pH 6, for which a qmax of 244 mg IgG g−1 MPs and Kd of 25 mg L−1 were obtained. Increasing salt concentrations at a basic pH (1 mol L−1 NaCl at pH 11) were found to improve the elution of bound IgG. The MPs were challenged with an artificial protein mixture containing human IgG, albumin, insulin and apo-transferrin. An overall yield of 84% was achieved, retrieving 92% of bound IgG. CONCLUSIONS MPs were successfully used for the capture of monoclonal antibodies from two distinct mammalian cell cultures, a Chinese hamster ovary (CHO) and a hybridoma cell culture supernatants. The elution yields were high, ranging between 84% and 94%, with overall yields ranging from 72% to 88%. Final purities of 85% were reached for hybridoma cell supernatants. © 2014 Society of Chemical Industry

Photocurrent enhancement in thin a-Si:H solar cells due to the plasmonic light trapping is investigated, and correlated with the morphology and the optical properties of the self-assembled silver nanoparticles incorporated in the cells’ back reflector.

This study addresses for the first time the issue of pigeon (genus Columba) phylogeny within the archipelagos of Madeira ( Columba trocaz) and Azores ( C. palumbus azorica), located in the singular biogeographic area of Macaronesia. The phylogeny of these endemic pigeons was inferred based on mitochondrial (cytochrome b and cytochrome c oxidase I) and nuclear ($\beta$-fibrinogen intron 7) genetic markers through multiple approaches. Despite the non-monophyletic pattern for the insular endemic species recovered in the phylogenies, topology tests presented somewhat different results. C. trocaz, the Madeiran endemic species, clustered strongly with the Canarian endemic C. bollii, and these two are thus more closely related to each other than C. bollii to C. junoniae, the other endemic species of Canary Islands, which seems to have diverged independently. Moreover, C. trocaz was found to be phylogenetically closer to C. bollii than to C. palumbus from mainland Europe and Azores Islands. No genetic differentiation was found between the continental C. p. palumbus and the endemic C. p. azorica, which suggests a relatively recent colonisation event of the Azores Islands. (English) [ABSTRACT FROM AUTHOR]

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The increase of conductivity of electrolytes favors the current production in microbial fuel cells (MFCs). Adaptation of cell cultures to higher ionic strength is a promising strategy to increase electricity production. The bacterium Geobacter sulfurreducens is considered a leading candidate for MFCs. Therefore, it is important to evaluate the impact of the ionic strength on the functional properties of key periplasmic proteins that warrants electron transfer to cell exterior. The effect of the ionic strength on the functional properties of triheme cytochrome PpcA, the most abundant periplasmic cytochrome in G. sulfurreducens, was investigated by NMR and potentiometric methods. The redox properties of heme IV are the most affected ones. Chemical shift perturbation measurements on the backbone NMR signals, at increasing ionic strength, also showed that the region close to heme IV is the most affected due to the large number of positively charged residues, which confer a highly positive electrostatic surface around this heme. The shielding of these positive charges at high ionic strength explain the observed decrease in the reduction potential of heme IV and shows that PpcA was designed to maintain its functional mechanistic features even at high ionic strength.

The design of small interfering RNA (siRNA) delivery materials showing efficacy in vivo is at the forefront of nanotherapeutics research. Polyurea (PURE-type) dendrimers are 'smart' biocompatible 3D polymers that unveil a dynamic and elegant back-folding mechanism involving hydrogen bonding between primary amines at the surface and tertiary amines and ureas at the core. Similarly, to a biological proton pump, they are able to automatically and reversibly transform their conformation in response to pH stimulus. Here, we show that PURE-G4 is a useful gene silencing platform showing no cellular toxicity. As a proof of concept we investigated the PURE-G4-siRNA dendriplex, which was shown to be an attractive platform with high transfection efficacy. The simplicity associated with the complexation of siRNA with polyurea dendrimers makes them a powerful tool for efficient cytosolic siRNA delivery.

Reverse electrodialysis (RED) is a sustainable technology for salinity gradient energy harvesting. In order to make the process economically competitive, it is desirable to operate it at the highest possible net power density, which depends on the RED stack geometry and on the pressure drop along its pathways and, thus, on the energy spent for solutions pumping. The fluid flow in RED stacks generally occurs in rectangular compartment channels, equipped with spacers. The effects of spacers design and properties have been studied extensively in recent years. However, the other possible causes for a RED stack and their relative impact on the process performance have not yet been systematically studied. In this study the partial pressure drops in (1) distribution ducts, (2) branches, (3) beams, (4) due to sudden section expansion between the beam and the compartment channel and (5) in the compartment channel were taken into consideration. A model for the total pressure drop inside a RED stack, with a parallel fluid flow distribution through the compartments, is proposed and experimentally validated for lab-scale RED stacks with sheet flow spacers and compared with an open channel (spacer-free) design. The importance of each partial pressure drop was then evaluated quantitatively through model simulations for industrial-scale stacks with an increasing number of cell pairs. It was found that the net power density decreases when the cell-pair number increases, since the partial pressure drop in the branches becomes dominant. Moreover, the possible reasons for a non-uniform fluid flow distribution are discussed, thus making the proposed model useful for planning and/or optimization of RED stacks design.

Nanoenabled technology holds great potential for health issues and biological research. Among the numerous inorganic nanoparticles that are available today, gold nanoparticles are fully developed as therapeutic and diagnostic agents both in vitro and in vivo due to their physicochemical properties. Owing to this, substantial work has been conducted in terms of developing biosensors for noninvasive and targeted tumor diagnosis and treatment. Some studies have even expanded into clinical trials. This article focuses on the fundamentals and synthesis of gold nanoparticles, as well as the latest, most promising applications in cancer research, such as molecular diagnostics, immunosensors, surface-enhanced Raman spectroscopy and bioimaging. Challenges to their further translational development are also discussed.

Proton nuclear magnetic resonance (H-1 NMR) relaxometry, over about five decades in Larmor frequency, and pulsed field gradient NMR were used to study the molecular dynamics in the chromonic nematic and isotropic phases of stacked molecules of the binary mixture composed by Edicol Sunset Yellow (ESY) and deuterated water. Our results evidence that in both phases collective motions are responsible for the spin-lattice relaxation dispersion in the Larmor frequency range below 1 MHz. In the nematic phase, the collective motion are attributed to columnar undulations within the stacked molecules, while, in the isotropic phase, the results are explained by local order fluctuations due to the formation of the stacks. The high frequency dispersion was explained by individual molecular motions like rotations around and perpendicular to the stack axis, and also self-diffusion.