title: Characterization of the effect of NaCl and trehalose on the thermotropic hysteresis of DOPC lipids during freeze/thaw.
abstract: This study characterizes the freeze/thaw behavior of large unilamellar DOPC vesicles in the presence of 0.5 or 4 M NaCl and 73 to 146 mM trehalose using Fourier transform infrared (FTIR) spectroscopy. Differences in lipid hydration between cooling and heating caused hysteresis in lipid phase change behavior and altered post-thaw lipid chain order. Lipids transitioned to a more ordered state during cooling. However, with heating, there was further conversion to a more ordered state at temperatures lower than the chain melting temperature. This conversion was more pronounced at higher concentrations of NaCl due to the formation of NaCl dihydrate crystals and the resulting changes in lipid hydration. Trehalose was shown to be capable of abrogating the severe dehydration effect at sufficiently high trehalose/NaCl concentrations by suppressing the formation of the NaCl dihydrate crystals. Moreover, trehalose enhanced recovery of prefreeze membrane structure.
authors.affiliation: Biostabilization Laboratory, Mechanical Engineering Department, College of Science and Engineering, University of Minnesota, Minneapolis, Minnesota 55455, USA.
authors.forename: Vishard
authors.initials: V
authors.lastname: Ragoonanan
authors.forename: Timothy
authors.initials: T
authors.lastname: Wiedmann
authors.forename: Alptekin
authors.initials: A
authors.lastname: Aksan
mesh_terms: D002152:Calorimetry, Differential Scanning; D044367:Phase Transition; D010713:Phosphatidylcholines / Q000737:chemistry*; D012965:Sodium Chloride / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D044366:Transition Temperature; D014199:Trehalose / Q000737:chemistry*; D053835:Unilamellar Liposomes / Q000737:chemistry
chemical_list: D010713:Phosphatidylcholines; D053835:Unilamellar Liposomes; D012965:Sodium Chloride; D014199:Trehalose; C017251:1,2-oleoylphosphatidylcholine