Universality of DNA Adsorption Behavior on the Cationic Membranes of Nanolipoplexes.

Nanolipoplexes have emerged worldwide as the most pRev.alent synthetic gene delivery system. Nowadays, it is accepted that complete DNA protection and a precise control of the physical attributes of emerging complexes are major steps toward rational design of efficient nanocarriers. Here we Rev.ise the mechanism of DNA adsorption to the cationic membranes of lipid nanovectors. Here we show that both the DNA-binding ability of cationic membranes and the one-dimensional DNA packing density inside the complex depen on the cationic lipid/anionic DNA charge ratio. Remarkably, both these distributions are rescaled on universal curves when plotted against γ, a dimensionless quantity expressing the ratio between the area of cationic membranes and that occupied by DNA molecules. As a result, the DNA condensation on the surface of lipid nanocarriers can be regarded as a two-step process. Our findings indicate a successful way to the rational design of next-generation drug delivery nanocarriers

SAXSDOG: open software for real-time azimuthal integration of 2D scattering images

In situ small- and wide-angle scattering experiments at synchrotrons often result in massive quantities of data within just seconds. Especially during such beamtimes, processing of the acquired data online, without appreciable delay, is key to obtaining feedback on the failure or success of the experiment. This had led to the development of SAXSDOG, a Python-based environment for real-time azimuthal integration of large-area scattering images. The software is primarily designed for dedicated data pipelines: once a scattering image is transferred from the detector onto the storage unit, it is automatically integrated and pre-evaluated using integral parameters within milliseconds. The control and configuration of the underlying server-based processes is achieved via a graphical user interface, SAXSLEASH, which visualizes the resulting 1D data together with integral classifiers in real time. SAXSDOG further includes a portable ‘take-home’ version for users that runs on standalone computers, enabling its use in laboratories or at the preferred workspace

Control of silver-polymer aggregation mechanism by primary particle spatial correlations in dynamic fractal-like geometry

Silver nanocrystals have been prepared by reacting silver nitrate with ascorbic acid in aqueous solution containing a low concentration of a commercial polynaphtalene sulphonate polymer (Daxad 19). Various crystalline morphologies have been obtained simply by tuning the reaction temperature. We have investigated the nanoparticle formation mechanism at three different temperatures by in situ and time resolved Small Angle X ray Scattering measurements. By modeling the scattering intensity with interacting spherical particles in a fractal-like polymer-Ag matrix, we found signatures of nucleation, growth and assembly of primary particles of about 15-20 nm. We observed how the time evolution of both spatial correlations between primary particles and the dynamic fractal geometry of the polymer-Ag matrix could influence and determine both the aggregation mechanism and the morphology of forming nanostructures in solution

Author Correction: Salt concentration and charging velocity determine ion charge storage mechanism in nanoporous supercapacitors

Correction to: Nature Communications; https://doi.org/10.1038/s41467-018-06612-4; published online 08 October 2018 The original version of this Article contained an error in the Acknowledgements, which was incorrectly omitted from the end of the following: ‘The research leading to these results has received funding from the European Community’s Horizon 2020 Framework Programme under grant agreement nº 730872.’ This has been corrected in both the PDF and HTML versions of the Article

In situ electrochemical grazing incidence small angle X-ray scattering: From the design of an electrochemical cell to an exemplary study of fuel cell catalyst degradation

Nowadays, electrochemistry has a considerable technological impact, involving fuel cells, super capacitors and batteries. These devices are based on complex architectures, which complicates monitoring their evolution in situ under operating conditions to reveal the reasons for reduced lifetime and performances. Here, we present a design of a multipurpose electrochemical cell for grazing incidence small and wide angle X-ray scattering (GISAXS and GIWAXS) where the environment for operating conditions can be recreated. We focus on proton exchange membrane fuel cells (PEMFCs) which operational conditions are simulated by means of potentiodynamic-based accelerated stress tests, applied to a thin film of Pt nanoparticles representing a model system of a benchmark catalyst. Two different upper potentials are used to mimic fuel cell operating conditions: at 1.0 V RHE the catalyst film preserves its initial morphology, while at 1.5 V RHE (simulating fuel cell start-up/shut-down cycles) significant coarsening has been observed. The initial dimension of the Pt particles of 4.0 nm increases to 8.7 nm due to the predominant process of coalescence and final Ostwald ripening. In parallel, the distance between the particles increases, the catalyst film (9 nm thick) becomes thinner at first and exhibit a higher roughness at the end