title: Effect of substitution of hydrogen oxide by deuterium oxide on thermotropic transition between the interdigitated gel phase and the ripple phase of dihexadecylphosphatidylcholine.
abstract: Thermotropic transitions of dihexadecylphosphatidylcholine (DHPC) dispersions in hydrogen oxide (1H2O) and deuterium oxide (2H2O) were investigated by differential scanning calorimetry (DSC). In DHPC dispersions, transition temperature between interdigitated gel phase (L beta I) and ripple phase (P beta') is lower in 2H2O than in 1H2O, and transition between the ripple phase (P beta') and fluid phase (L alpha) in 2H2O occurs at a temperature slightly higher than in 1H2O. In dipalmitoylphosphatidylcholine (DPPC) dispersions, on the other hand, transition temperature between lamellar gel phase (L beta') and ripple phase is higher in 2H2O than in 1H2O. These results suggest that the interdigitated gel phase is more stable in 1H2O than in 2H2O. To account for the shift of transition temperature by the water substitution, difference of interfacial energies between these aqueous environments is discussed.
authors.affiliation: Department of Applied Physics, School of Engineering, Nagoya University, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Ohki
mesh_terms: D002152:Calorimetry, Differential Scanning; D003903:Deuterium / Q000378:metabolism*; D017666:Deuterium Oxide; D006878:Hydroxides / Q000378:metabolism*; D017665:Hydroxyl Radical; D008567:Membranes, Artificial; D010742:Phospholipid Ethers / Q000378:metabolism*; D012995:Solubility; D013816:Thermodynamics; D014867:Water / Q000378:metabolism*
chemical_list: C052298:1,2-dihexadecyl-sn-glycero-3-phosphocholine; D006878:Hydroxides; D008567:Membranes, Artificial; D010742:Phospholipid Ethers; D014867:Water; D017665:Hydroxyl Radical; D003903:Deuterium; D017666:Deuterium Oxide