title: Effect of oligomers of ethylene glycol on thermotropic phase transition of dipalmitoylphosphatidylcholine multilamellar vesicles.
abstract: The effect of oligomers of ethylene glycol (EG) on thermotropic phase transitions of dipalmitoylglycerophosphatidylcholine multilamellar vesicles (DPPC-MLV) were investigated. Diethylene glycol (di-EG) had a biphasic effect on transition temperature, reducing pre-transition temperature (Tp) at low concentrations but increasing main transition temperature (Tm) and extinguishing pre-transition at high concentration. Results of the X-ray diffraction method and the excimer method indicated that di-EG induced interdigitated gel phase (L beta 1 phase) in the DPPC membranes at high concentration. Phase diagram of temperature-di-EG concentration for DPPC-MLV was determined by use of X-ray diffraction and differential scanning calorimetry, which was similar to that of temperature-EG concentration. The minimum concentration of di-EG where L beta 1 phase was induced was 42%(w/v), which was larger than that of EG (30%(w/v)). On the other hand, in the presence of triethylene glycol (tri-EG), Tm and Tp increased with an increased in tri-EG concentration, as well as poly(ethylene glycol). These differences, between the effects of di-EG and those of tri-EG, might be due to the differences of their sizes.
authors.affiliation: Department of Physics, Faculty of Science, Shizuoka University, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Yamazaki
authors.forename: N
authors.initials: N
authors.lastname: Kashiwagi
authors.forename: M
authors.initials: M
authors.lastname: Miyazu
authors.forename: T
authors.initials: T
authors.lastname: Asano
mesh_terms: D015060:1,2-Dipalmitoylphosphatidylcholine / Q000737:chemistry*; D002152:Calorimetry, Differential Scanning; D019855:Ethylene Glycol; D005026:Ethylene Glycols / Q000494:pharmacology*; D006358:Hot Temperature; D008566:Membranes / Q000737:chemistry*; D011092:Polyethylene Glycols / Q000494:pharmacology; D011108:Polymers / Q000494:pharmacology; D013696:Temperature
chemical_list: D005026:Ethylene Glycols; D011108:Polymers; D015060:1,2-Dipalmitoylphosphatidylcholine; C028914:triethylene glycol; D011092:Polyethylene Glycols; D019855:Ethylene Glycol