| 1. |
- Nappini, S., et al.
(author)
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Soft x-ray spectroscopies in liquids and at solid-liquid interface at BACH beamline at Elettra
- 2021
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In: Review of Scientific Instruments. - : American Institute of Physics (AIP). - 0034-6748 .- 1089-7623. ; 92:1
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Journal article (peer-reviewed)abstract
- The beamline for advanced dichroism of the Istituto Officina dei Materiali-Consiglio Nazionale delle Ricerche, operating at the Elettra synchrotron in Trieste (Italy), works in the extreme ultraviolet-soft x-ray photon energy range with selectable light polarization, high energy resolution, brilliance, and time resolution. The beamline offers a multi-technique approach for the investigation of the electronic, chemical, structural, magnetic, and dynamical properties of materials. Recently, one of the three end stations has been dedicated to experiments based on electron transfer processes at the solid/liquid interfaces and during photocatalytic or electrochemical reactions. Suitable cells to perform soft x-ray spectroscopy in the presence of liquids and reagent gases at ambient pressure were developed. Here, we present two types of static cells working in transmission or in fluorescence yield and an electrochemical flow cell that allows us to carry out cyclic voltammetry in situ and electrodeposition on a working electrode and to study chemical reactions under operando conditions. Examples of x-ray absorption spectroscopy measurements performed under ambient conditions and during electrochemical experiments in liquids are presented.
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| 2. |
- Nappini, S., et al.
(author)
-
Controlled drug release under a low frequency magnetic field: effect of the citrate coating on magnetoliposomes stability
- 2011
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In: Soft Matter. - : Royal Society of Chemistry (RSC). - 1744-6848 .- 1744-683X. ; 7:3, s. 1025-1037
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Journal article (peer-reviewed)abstract
- The paper describes the effect of a low-frequency alternating magnetic field (LF-AMF) on the permeability and release properties of large (LUVs) and giant (GUVs) unilamellar vesicles loaded with citrate coated cobalt ferrite nanoparticles (NPs). The citrate shell allows a high loading of NPs in lipid vesicles without modifying their magnetic properties. The increase of magnetic LUVs permeability upon exposure to LF-AMF has been evaluated as the fluorescence self-quenching of carboxyfluorescein (CF) entrapped inside the liposome aqueous pool. Liposome leakage has been monitored as a function of field frequency, time exposure and concentration of the citrate coated NPs. Confocal Laser Scanning Microscopy (CLSM) experiments performed on magnetic GUVs labeled with the fluorescent probe DiIC18 and loaded with Alexa 488-C5-maleimide fluorescent dye provided insights on the release mechanism induced by LF-AMF. The results show that LF-AMF strongly affects vesicles permeability, suggesting the formation of pores in the lipid bilayer due to both hyperthermic effects and nanoparticle oscillations in the vesicles pool at the applied frequency. The behaviour of these magnetic vesicles in the presence of LF-AMF makes this system a good candidate for controlled drug delivery.
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| 3. |
- Nappini, S., et al.
(author)
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Magnetically Triggered Release From Giant Unilamellar Vesicles: Visualization By Means Of Confocal Microscopy
- 2011
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In: Journal of Physical Chemistry Letters. - : American Chemical Society (ACS). - 1948-7185. ; 2:7, s. 713-718
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Journal article (peer-reviewed)abstract
- Magnetically triggered release from magnetic giant unilamellar vesicles (GUVs) loaded with Alexa fluorescent dye was studied by means of confocal laser scanning microscopy (CLSM) under a low-frequency alternating magnetic field (LF-AMP). Core/shell cobalt ferrite nanoparticles coated with rhodamine B isothiocyanate (MP@SiO2(RITC)) were prepared and adsorbed on the GUV membrane. The MP@SiO2-(RITC) location and distribution on giant lipid vesicles were determined by 3D-CLSM projections, and their effect on the release properties and GUV permeability under a LF-AMF was investigated by CLSM time-resolved experiments. We show that the mechanism of release of the fluorescent dye during the LF-AMF exposure is induced by magnetic nanoparticle energy and mechanical vibration, which promote the perturbation of the GUV membrane without its collapse.
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