Biological and confined water in metastable states

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Biological and confined water in metastable states
Martedì 18 maggio alle ore 15:00, Gaia Camisasca del Dipartimento di Matematica e Fisica, Università Roma Tre, terrà il Colloquio di Fisica dal titolo " Biological and confined water in metastable states".

Water plays relevant roles in many phenomena taking place in biology and nanotechnology. In many situations water is found in thermodynamical metastable regimes, either in the supercooled regime where water is in the liquid phase but at very low temperatures, or in extremely strong confinement.
In this seminar I will focus on two different applications which leverage these metastabilities of water: the first is the case of water in contact with biomolecules important for cryopreservation and the second is the case of water confined in nano-scale porous materials widely employed in technological devices. 
In the first part of the talk, we study the cryoprotective mechanism of trehalose-water solutions on proteins. In the cryopreservation of biomaterials like proteins, stem cells, tissues, and foods, the materials are immersed in aqueous solutions and preserved by being cooled down to very low temperatures, well below the melting temperature of water.  The addition of excipients to water is essential to prevent ice growth which can damage biomaterials. The sugar trehalose is a very effective bio-compatible excipients but the microscopic mechanism behind its bioprotection is still matter of debate.
In the second part of the talk, I will focus on water confined inside cylindrical nanopores, where water can evaporate at temperatures much lower than in the bulk phase causing the formation of a vapour pocket – a bubble – inside the nanopores. Today many devices used for energy storage and release, shock bumpers, nanopore sensing, and chromatography, rely on the drying-wetting properties of nanopores. In this study we use rare-event methods to characterize the mechanism of the confined bubble formation in presence of diluted hydrophobic gas. Implications for the action of anesthetics on biological channels will be also discussed.
G. Camisasca, M. De Marzio, P. Gallo, “Effect of trehalose on protein cryoprotection: Insights into the mechanism of slowing down of hydration water”, J. Chem. Phys. 153, 224503 (2020)
G. Camisasca, A. Tinti, A. Giacomello, “Gas-Induced Drying of Nanopores”, J. Phys. Chem. Lett. 11, 9171–9177 (2020)


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