Browsing by Author "Dichiarante, Valentina"

Now showing 1 - 5 of 5
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    Evaluating the potential of natural surfactants in the petroleum industry: The case of hydrophobins
    (2018-02) Blesic, Marijana; Dichiarante, Valentina; Milani, Roberto; Linder, Markus; Metrangolo, Pierangelo; Department of Bioproducts and Biosystems; Department of Applied Physics; Biomolecular Materials; Polytechnic University of Milan; VTT Technical Research Centre of Finland
    Enhancing oil recovery from currently available reservoirs is a major issue for petroleum companies. Among the possible strategies towards this, chemical flooding through injection of surfactants into the wells seems to be particularly promising, thanks to their ability to reduce oil/water interfacial tension that promotes oil mobilization. Environmental concerns about the use of synthetic surfactants led to a growing interest in their replacement with surfactants of biological origin, such as lipopeptides and glycolipids produced by several microorganisms. Hydrophobins are small amphiphilic proteins produced by filamentous fungi with high surface activity and good emulsification properties, and may represent a novel sustainable tool for this purpose. We report here a thorough study of their stability and emulsifying performance towards a model hydrocarbon mixture, in conditions that mimic those of real oil reservoirs (high salinity and high temperature). Due to the moderate interfacial tension reduction induced in such conditions, the application of hydrophobins in enhanced oil recovery techniques does not appear feasible at the moment, at least in absence of co-surfactants. On the other hand, the obtained results showed the potential of hydrophobins in promoting the formation of a gel-like emulsion 'barrier' at the oil/water interface.
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    Halogen bond-assisted self-assembly of gold nanoparticles in solution and on a planar surface
    (The Royal Society of Chemistry, 2019-10-21) Buntara Sanjeeva, Kavitha; Pigliacelli, Claudia; Gazzera, Lara; Dichiarante, Valentina; Baldelli Bombelli, Francesca; Metrangolo, Pierangelo; Polytechnic University of Milan; Department of Applied Physics
    Halogen bonding (XB) has been shown to be a powerful tool for promoting molecular self-assembly in different fields. The use of XB for noncovalent assembly of inorganic nanoparticles (NP) is, instead, quite limited, considering how extensively other interactions (i.e., electrostatic forces, hydrophobic effect, hydrogen bonding, etc.) have been exploited to modulate and program NP self-assembly. Here, we designed and synthesized XB-capable organic ligands that were efficiently used to functionalize the surface of gold NPs (AuNPs). XB-assisted AuNP self-assembly was attained in solution mixing AuNPs bearing XB-donor ligands with ditopic XB-acceptor molecules and AuNPs functionalized with XB-acceptor moieties. Likewise, a preliminary study of XB-driven adsorption of these AuNPs on surface was performed via Quartz Crystal Microbalance with Dissipation Monitoring (QCM-D), used as an in situ tool for measuring mass changes upon XB-driven self-assembly.
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    Halogen-bonded mesogens direct polymer self-assemblies up to millimetre length scale
    (2014) Houbenov, Nikolay; Milani, Roberto; Poutanen, Mikko; Haataja, Johannes; Dichiarante, Valentina; Sainio, Jani; Ruokolainen, Janne; Resnati, Giuseppe; Metrangolo, Pierangelo; Ikkala, Olli; Department of Applied Physics; Surface Science
    Aligning polymeric nanostructures up to macroscale in facile ways remains a challenge in materials science and technology. Here we show polymeric self-assemblies where nanoscale organization guides the macroscopic alignment up to millimetre scale. The concept is shown by halogen bonding mesogenic 1-iodoperfluoroalkanes to a star-shaped ethyleneglycol-based polymer, having chloride end-groups. The mesogens segregate and stack parallel into aligned domains. This leads to layers at ~10 nm periodicity. Combination of directionality of halogen bonding, mesogen parallel stacking and minimization of interfacial curvature translates into an overall alignment in bulk and films up to millimetre scale. Upon heating, novel supramolecular halogen-bonded polymeric liquid crystallinity is also shown. As many polymers present sites capable of receiving halogen bonding, we suggest generic potential of this strategy for aligning polymer self-assemblies.
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    High-resolution crystal structure of a 20 kDa superfluorinated gold nanocluster
    (Nature Publishing Group, 2022-05-11) Pigliacelli, Claudia; Acocella, Angela; Diez, Isabel; Moretti, Luca; Dichiarante, Valentina; Demitri, Nicola; Jiang, Hua; Maiuri, Marghareta; Ras, Robin; Baldelli Bombelli, Francesca; Cerullo, Giulio; Zerbetto, Francesco; Metrangolo, Pierangelo; Terraneo, Giancarlo; Department of Applied Physics; Department of Bioproducts and Biosystems; Soft Matter and Wetting; Universitá di Bologna; Politecnico di Milano; Sincrotrone Trieste
    Crystallization of atomically precise nanoclusters is gaining increasing attention, due to the opportunity of elucidating both intracluster and intercluster packing modes, and exploiting the functionality of the resulting highly pure crystallized materials. Herein, we report the design and single-crystal X-ray structure of a superfluorinated 20 kDa gold nanocluster, with an Au25 core coated by a shell of multi-branched highly fluorinated thiols (SF27) resulting in almost 500 fluorine atoms, i.e., ([Au25(SF27)18]0). The cluster shows a switchable solubility in the fluorous phase. X-ray analysis and computational studies reveal the key role of both intracluster and intercluster F···F contacts in driving [Au25(SF27)18]0 crystal packing and stabilization, highlighting the ability of multi-branched fluorinated thiols to endow atomically precise nanoclusters with remarkable crystallogenic behavior.
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    Hydrophobin-Coated Solid Fluorinated Nanoparticles for 19F-MRI
    (Wiley-Blackwell, 2022-06-22) Ayaz, Nazeeha; Dichiarante, Valentina; Pigliacelli, Claudia; Repossi, Jacopo; Gazzera, Lara; Borreggio, Marta; Maiolo, Daniele; Chirizzi, Cristina; Bergamaschi, Greta; Chaabane, Linda; Fasoli, Elisa; Metrangolo, Pierangelo; Baldelli Bombelli, Francesca; Department of Applied Physics; Centre of Excellence in Molecular Engineering of Biosynthetic Hybrid Materials research; Polytechnic University of Milan; CNR-ENEA-EURATOM Association; IRCCS San Raffaele Scientific Institute
    In recent years, fluorine-magnetic resonance imaging (19F-MRI) has emerged as a promising diagnostic technique, complementary to traditional proton magnetic resonance imaging (1H-MRI) and easily translatable for clinical use, providing in-depth in vivo quantification without the use of radioactive agents. This creates a need for the development of appropriate delivery systems for highly omniphobic fluorinated probes. The use of the film-forming protein hydrophobin (HFBII) represents a sustainable and simple method to invert the philicity of fluorinated surfaces. Here, the ability of HFBII to form a rigid protein monolayer on superfluorinated coatings rendering them hydrophilic is shown, a property that is also retained in biological environment. This approach is then translated to directly disperse a solid superfluorinated 19F-MRI probe, PERFECTA, in aqueous solution through the formation of core-shell hydrophobin stabilized PERFECTA nanoparticles (NPs). The obtained NPs are fully characterized in terms of morphology, magnetic properties, colloidal stability, protein corona formation, cellular viability, and imaging performance.