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Marina di Pisa, Italy

Grasso G.,University of Catania | Salomone F.,University of Catania | Salomone F.,Center for Nanotechnology Innovation | Tundo G.R.,University of Rome Tor Vergata | And 11 more authors.
Journal of Inorganic Biochemistry | Year: 2012

Insulin degradation is a finely tuned process that plays a major role in controlling insulin action and most evidence supports IDE (insulin-degrading enzyme) as the primary degradative agent. However, the biomolecular mechanisms involved in the interaction between IDE and its substrates are often obscure, rendering the specific enzyme activity quite difficult to target. On the other hand, biometals, such as copper, aluminum and zinc, have an important role in pathological conditions such as Alzheimer's disease or diabetes mellitus. The metabolic disorders connected with the latter lead to some metallostasis alterations in the human body and many studies point at a high level of interdependence between diabetes and several cations. We have previously reported (Grasso et al., Chem. Eur. J. 17 (2011) 2752-2762) that IDE activity toward Aβ peptides can be modulated by metal ions. Here, we have investigated the effects of different metal ions on the IDE proteolytic activity toward insulin as well as a designed peptide comprising a portion of the insulin B chain (B20-30), which has a very low affinity for metal ions. The results obtained by different experimental techniques clearly show that IDE is irreversibly inhibited by copper(I) but is still able to process its substrates when it is bound to copper(II). © 2012 Elsevier Inc. All rights reserved. Source


Dal Maschio M.,Italian Institute of Technology | Ghezzi D.,Italian Institute of Technology | Bony G.,Italian Institute of Technology | Alabastri A.,Italian Institute of Technology | And 9 more authors.
Nature Communications | Year: 2012

In utero electroporation is a powerful tool to transfect and manipulate neural-precursor cells of the rodent parietal cortex and their progeny in vivo. Although this technique can potentially target numerous brain areas, reliability of transfection in some brain regions is low or physical access is limited. Here we present a new in utero electroporation configuration based on the use of three electrodes, the relative position and polarities of which can be adjusted. The technique allows easy access and exceedingly reliable monolateral or bilateral transfection at brain locations that could only be sporadically targeted before. By improvement in the efficiency of the electrical field distribution, demonstrated here by a mathematical simulation, the multi-electrode configuration also extends the developmental timeframe for reliable in utero electroporation, allowing for the first time specific transfection of Purkinje cells in the rat cerebellum. © 2012 Macmillan Publishers Limited. All rights reserved. Source


Roddaro S.,CNR Institute of Neuroscience | Pescaglini A.,CNR Institute of Neuroscience | Ercolani D.,CNR Institute of Neuroscience | Sorba L.,CNR Institute of Neuroscience | And 3 more authors.
Nano Research | Year: 2011

The controlled tailoring of the energy distribution in an electron system opens the way to interesting new physics and device concepts, as demonstrated by research on metallic nanodevices during recent years. Here we investigate how Josephson coupling in a superconductor-InAs nanowire junction can be tuned by means of hot-electron injection and we show that a complete suppression of superconductive effects can be achieved using a power as low as 100 pW. Nanowires offer a novel design freedom as they allow axial and radial heterostructures to be defined as well as control over doping profiles, which can be crucial in the development of devices-such as nanorefrigerators-where precisely controlled and predictable energy barriers are mandatory. Our work provides estimates for unknown key thermal and electrical parameters, such as the electron-phonon coupling, in our InAs nanostructures. © 2010 Tsinghua University Press and Springer-Verlag Berlin Heidelberg. Source


Pavan G.M.,University of Applied Sciences and Arts Southern Switzerland | Albertazzi L.,CNR Institute of Neuroscience | Albertazzi L.,Center for Nanotechnology Innovation | Danani A.,University of Applied Sciences and Arts Southern Switzerland
Journal of Physical Chemistry B | Year: 2010

This paper reports a molecular dynamic study to explore the diverse behavior of different generations of poly(amidoamine) (PAMAM) dendrimers in binding siRNA. Our models show good accordance with experimental measurements. Simulations demonstrate that the molecular flexibility of PAMAMs plays a crucial role in the binding event, which is controlled by the modulation between enthalpy and entropy of binding. Importantly, the ability of dendrimers to adapt to siRNA is strongly dependent on the generation and on the pH due to backfolding. While G4 demonstrates good adaptability to siRNA, G6 behaves like a rigid sphere with a consistent loss in the binding affinity. G5 shows a hybrid behavior, maintaining rigid and flexible aspects, with a strong dependence of its properties on the pH. To define the "best binder", the mere energetic definition of binding affinity appears to be no longer effective and a novel concept of "efficiency" should be considered, being the balance between enthalpy and entropy of binding indivisible from the structural flexibility. With this aim, we propose an original criterion to define and rank the ability of these molecules to adapt their structure to bind a charged target. © 2010 American Chemical Society. Source


Albertazzi L.,TU Eindhoven | Storti B.,Center for Nanotechnology Innovation | Brondi M.,Center for Nanotechnology Innovation | Sato S.S.,Center for Nanotechnology Innovation | And 3 more authors.
Journal of Visualized Experiments | Year: 2013

The development of fluorescent indicators represented a revolution for life sciences. Genetically encoded and synthetic fluorophores with sensing abilities allowed the visualization of biologically relevant species with high spatial and temporal resolution. Synthetic dyes are of particular interest thanks to their high tunability and the wide range of measureable analytes. However, these molecules suffer several limitations related to small molecule behavior (poor solubility, difficulties in targeting, often no ratiometric imaging allowed). In this work we introduce the development of dendrimer-based sensors and present a procedure for pH measurement in vitro, in living cells and in vivo. We choose dendrimers as ideal platform for our sensors for their many desirable properties (monodispersity, tunable properties, multivalency) that made them a widely used scaffold for several biomedical devices. The conjugation of fluorescent pH indicators to the dendrimer scaffold led to an enhancement of their sensing performances. In particular dendrimers exhibit reduced cell leakage, improved intracellular targeting and allow ratiometric measurements. These novel sensors were successfully employed to measure pH in living HeLa cells and in vivo in mouse brain. Source

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