DMSO-induced perturbation of thermotropic properties of cholesterol-containing DPPC liposomes.
Dimethyl sulfoxide (DMSO) is a universal solvent widely used in many fields, from basic research to industrial applications. At low concentration, it is the most important cryoprotectant agent against cellular damage caused during a freeze-thaw cycle. Although the effects of this cosolvent on the physico-chemical properties of a lipid bilayer have been extensively studied with both in vitro and in vivo experiments, the molecular mechanism of cryopreservation is not completely understood. Cholesterol (Chol) represents one of the essential cell membrane component and is fundamental to maintain the integrity and fluidity of the membrane. Here we report a study on the effect of DMSO on the stability of Chol-containing model membranes. We investigated the effect of DMSO on thermal stability of model membranes formed by dipalmitoylphospatidylcholine (DPPC) and DPPC/Chol by means of Fourier Transform Infrared Spectroscopy (FT-IR) and Differential Scanning Calorimetry (DSC) measurements. It is well known that cholesterol reduces the thermal stability of DPPC vesicles and also the pre-transition is abolished. Our results show that DMSO induces a stabilization of the lipid bilayer of DPPC liposomes increasing both the pre- and main transition temperatures. In DPPC/Chol liposomes a similar thermal stabilization was observed for the main transition indicating that DMSO is capable to stabilize the lipid bilayer even in the presence of the sterol. Moreover, by direct inspection of the hydration degree of the lipid bilayers, we evidenced the role played by DMSO on the thermal stability of the membrane as connected to the hydration of the polar head groups.
Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia, Via Elce di Sotto 8, 06123 Perugia, Italy.
Maria
M
Ricci
Dipartimento di Scienze Chimiche, Università di Napoli "Federico II", Via Cintia, 21 - 80126 Napoli, Italy.
Rosario
R
Oliva
Dipartimento di Scienze Chimiche, Università di Napoli "Federico II", Via Cintia, 21 - 80126 Napoli, Italy.
Pompea
P
Del Vecchio
Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia, Via Elce di Sotto 8, 06123 Perugia, Italy.
Marco
M
Paolantoni
Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia, Via Elce di Sotto 8, 06123 Perugia, Italy.
Assunta
A
Morresi
Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia, Via Elce di Sotto 8, 06123 Perugia, Italy. Electronic address: paola.sassi@unipg.it.
Paola
P
Sassi
D015060:1,2-Dipalmitoylphosphatidylcholine / Q000737:chemistry*; D004121:Dimethyl Sulfoxide / Q000494:pharmacology*; D008051:Lipid Bilayers / Q000737:chemistry; D008081:Liposomes / Q000737:chemistry*; D013816:Thermodynamics
D008051:Lipid Bilayers; D008081:Liposomes; D015060:1,2-Dipalmitoylphosphatidylcholine; D004121:Dimethyl Sulfoxide
Cholesterol; DMSO; DPPC; DSC; FTIR