Scientific Results

Influence of Dimethyl Sulfoxide on the Low-Temperature Behavior of Cholesterol-Loaded Palmitoyl-oleyl-phosphatidylcholine Membranes

Year: 2018

Authors: Gironi B., Paolantoni M., Morresi A., Foggi P., Sassi P.

Autors Affiliation: Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia, Via Elce di Sotto 8, Perugia, 06123, Italy; European Laboratory for Non Linear Spectroscopy (LENS), Università di Firenze, via Nello Carrara 1, Sesto Fiorentino, Florence, 50019, Italy; CNR-INO, Via Nello Carrara 1, Sesto Fiorentino, Florence, 50019, Italy; CNR-ICCOM, Via Madonna del Piano 10, Sesto Fiorentino, Florence, 50019, Italy; Centro di Eccellenza sui Materiali Innovativi Nanostrutturati (CEMIN), Università di Perugia, Via Elce di Sotto 8, Perugia, 06123, Italy

Abstract: The properties of lipid membranes at low temperature are important for a number of biomedical and biotechnological applications, and the success of these applications depends on understanding the effects of temperature changes on intermolecular lipid-lipid and lipid-water interactions. Here, we use Fourier transform infrared spectroscopy to study lipid suspensions in water/dimethyl sulfoxide (DMSO) solutions in the -60 to 30 degrees C range. DMSO is a cryopreservative agent of cellular systems, and its action is largely related to its interaction with the lipid membrane, especially in the low- temperature regime. In the present work, we analyze the effects of solvent composition on the structural and thermotropic properties of cholesterol (chol)-loaded liposomes of palmitoyl-oleylphosphatidylcholine (POPC) because POPC/chol liposomes are suitable models of the plasmatic membrane. To this extent, we compare the properties of lipid vesicles suspended in water and water/DMSO solution at 0.10 DMSO mole fraction and we observe that the gel phase of the membrane has an increased thermal stability on DMSO addition. We estimate that the amount of unfrozen water at T = -60 degrees C is much reduced by the presence of DMSO, both in the gel- and the liquid-ordered phase of the membrane. Interestingly, we also evidence a reduced hydration of the lipid heads in the presence of DMSO when the vesicles are dispersed in a liquid solution, whereas the addition of DMSO does not alter the hydration state of phosphate and carbonyl groups in the frozen state of the membrane.

Journal/Review: JOURNAL OF PHYSICAL CHEMISTRY B

Volume: 122 (24)      Pages from: 6396  to: 6402

More Information: The authors are grateful to Prof. John Crowe (Univ. California-Davis) and Prof. Willem F. Wolkers (Leibniz Univ. Hannover) for the fruitful discussion and valuable suggestions. Authors acknowledge financial support from the Italian Centro Nazionale Trapianti by the project “Studio di cellule per uso clinico umano, con particolare riferimento a modelli cellulari (liposomi) e linee cellulari in interazione con crioconservanti e con materiali biocompatibili”; and the University of Perugia by the project “Fondo d’Ateneo per la ricerca di base 2014? Sintesi e caratterizzazione spettroscopica di nanoibridi per la diagnosi e il trattamento del glioblastoma”.
KeyWords: Cholesterol; Dimethyl sulfoxide; Fourier transform infrared spectroscopy; Hydration; Lipids; Liposomes; Membranes; Organic solvents, Biotechnological applications; Effects of temperature; Liquid-ordered phase; Low temperature behavior; Low-temperature regime; Phosphatidylcholine; Solvent composition; Thermotropic properties, Temperature
DOI: 10.1021/acs.jpcb.8b02333

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