The miscibility, stability and compressibility of L-<em>α</em> dioleoylphosphatidylcholine/rutin laurate mixed monolayer at the air/water were investigated by Langmuir film balance to reveal the character...The miscibility, stability and compressibility of L-<em>α</em> dioleoylphosphatidylcholine/rutin laurate mixed monolayer at the air/water were investigated by Langmuir film balance to reveal the characteristic of the molecular interaction. The two components of DOPC/RL mixed monolayer were miscible throughout the mixture composition range and at three experimental temperatures of 10<span style="white-space:nowrap;">°</span>C, 25<span style="white-space:nowrap;">°</span>C and 37<span style="white-space:nowrap;">°</span>C. At all experimental conditions, RL increased the compressibility and elasticity of the DOPC monolayer. Both the temperature and the composition of the membrane affected the form of intermolecular forces in the mixed monolayer.展开更多
Rutin was acylated with stearic acid in esterification reaction catalyzed by immobilized Candida antarctica lipase B(Novozym 435).The results suggested that the regioselectivity of the lipase-catalyzed esterification ...Rutin was acylated with stearic acid in esterification reaction catalyzed by immobilized Candida antarctica lipase B(Novozym 435).The results suggested that the regioselectivity of the lipase-catalyzed esterification of rutin was specific at the C4’’’ position of the rhamnose moiety.The monolayer of dioleoylphosphatidylcholine(DOPC) was used as the model membrane to study their molecular interaction with RS.The miscibility of DOPC/RS mixed monolayers has been investigated by Langmuir film balance to yield quantitative information on the nature of the molecular interaction,which could provide valuable insights to reveal the antioxidative activity mechanism of flavonoids.Pure RS and pure DOPC were capable of forming monolayers with liquid-phase at the air/water interface.The two components of DOPC/RS monolayer were miscible throunghout the mixture composition range.The effects of the temperature of the subphase on the miscibility and molecular interaction of DOPC/RS monolayers were investigated.The miscibility was more excellent at higher temperature.The condensing effect of RS,which represented the attractive forces between DOPC and RS,could be ascribed to the match of molecular shapes of RS and DOPC on the monolayers packing.展开更多
An amphiphilic ferrocene derivative 3-ferrocenyl-2-butylene acid(FCA) was synthesized. The mixed FCA/octadecylamine(ODA) monolayers on aqueous subphase were studied by means of surface pressure-molecule area(π-A) iso...An amphiphilic ferrocene derivative 3-ferrocenyl-2-butylene acid(FCA) was synthesized. The mixed FCA/octadecylamine(ODA) monolayers on aqueous subphase were studied by means of surface pressure-molecule area(π-A) isotherm, dπ/dA-A curve and the plot of the apparent area of ODA vs x(ODA). The results indicate that the FCA itself did not form monolayer, but the mixed FCA/ODA mono- layers were stable when the mole fraction of ODA was more than 25%, the mixed monolayers possessed the best stability and the highest incompressibility when the mole ratio of FCA to ODA is 1 to 1.展开更多
The domain structures of amphophilic molecules at the air-water interface have beenwidely studied by fluorescence and Brewster angle microscopy over the past ten years.However, these studies were mainly focused on the...The domain structures of amphophilic molecules at the air-water interface have beenwidely studied by fluorescence and Brewster angle microscopy over the past ten years.However, these studies were mainly focused on the transition from the liquid-expanded(LE) phase to the liquid-condensed (LC) phase in a one-component monolayer. Therewere only a few reports dealing with the direct observation of domain structures in展开更多
Morphology of dipalmitoyl phosphatidyl choline (DPPC)-cholesterol (Chol) mixed monolayer formed on water surface by dropping method was investigated using surface tension measurement (STm), Brewster angle microscopy (...Morphology of dipalmitoyl phosphatidyl choline (DPPC)-cholesterol (Chol) mixed monolayer formed on water surface by dropping method was investigated using surface tension measurement (STm), Brewster angle microscopy (BAM), and fluorescence microscopy (FM). STm showed strong condensation effect of Chol in fluidic DPPC monolayer. Excess area (S<sub>ex</sub>) from mean mixing state of DPPC and Chol was about twice larger than that by general compression method in the range from xC = 0.2 to 0.4 (xC: mole fraction of Chol). BAM and FM images showed clearly that the fluidic DPPC monolayer changed to condensed rigid monolayer due to the condensation effect of Chol. At more than xC = 0.3 DPPC-Chol mixed monolayer changed to condensed state similar to the Chol monolayer. These results support previous reports by compression method that Chol molecule demonstrates the strong condensation effect to the fluidic monolayer and also indicate that dropping method enables to form unique monolayer on the water surface.展开更多
Two-dimensional domain structures are normally formed at the air-water interface due to phase separation in mixed monolayers, in which their components are incompletely miscible. This provides us a chance for studying...Two-dimensional domain structures are normally formed at the air-water interface due to phase separation in mixed monolayers, in which their components are incompletely miscible. This provides us a chance for studying some quasi-two-dimensional phenomena in physics, such as phase separation and phase transition. On the other hand, mixed monolayers provide us a way of assembling several kinds of functional molecules into展开更多
文摘The miscibility, stability and compressibility of L-<em>α</em> dioleoylphosphatidylcholine/rutin laurate mixed monolayer at the air/water were investigated by Langmuir film balance to reveal the characteristic of the molecular interaction. The two components of DOPC/RL mixed monolayer were miscible throughout the mixture composition range and at three experimental temperatures of 10<span style="white-space:nowrap;">°</span>C, 25<span style="white-space:nowrap;">°</span>C and 37<span style="white-space:nowrap;">°</span>C. At all experimental conditions, RL increased the compressibility and elasticity of the DOPC monolayer. Both the temperature and the composition of the membrane affected the form of intermolecular forces in the mixed monolayer.
文摘Rutin was acylated with stearic acid in esterification reaction catalyzed by immobilized Candida antarctica lipase B(Novozym 435).The results suggested that the regioselectivity of the lipase-catalyzed esterification of rutin was specific at the C4’’’ position of the rhamnose moiety.The monolayer of dioleoylphosphatidylcholine(DOPC) was used as the model membrane to study their molecular interaction with RS.The miscibility of DOPC/RS mixed monolayers has been investigated by Langmuir film balance to yield quantitative information on the nature of the molecular interaction,which could provide valuable insights to reveal the antioxidative activity mechanism of flavonoids.Pure RS and pure DOPC were capable of forming monolayers with liquid-phase at the air/water interface.The two components of DOPC/RS monolayer were miscible throunghout the mixture composition range.The effects of the temperature of the subphase on the miscibility and molecular interaction of DOPC/RS monolayers were investigated.The miscibility was more excellent at higher temperature.The condensing effect of RS,which represented the attractive forces between DOPC and RS,could be ascribed to the match of molecular shapes of RS and DOPC on the monolayers packing.
文摘An amphiphilic ferrocene derivative 3-ferrocenyl-2-butylene acid(FCA) was synthesized. The mixed FCA/octadecylamine(ODA) monolayers on aqueous subphase were studied by means of surface pressure-molecule area(π-A) isotherm, dπ/dA-A curve and the plot of the apparent area of ODA vs x(ODA). The results indicate that the FCA itself did not form monolayer, but the mixed FCA/ODA mono- layers were stable when the mole fraction of ODA was more than 25%, the mixed monolayers possessed the best stability and the highest incompressibility when the mole ratio of FCA to ODA is 1 to 1.
文摘The domain structures of amphophilic molecules at the air-water interface have beenwidely studied by fluorescence and Brewster angle microscopy over the past ten years.However, these studies were mainly focused on the transition from the liquid-expanded(LE) phase to the liquid-condensed (LC) phase in a one-component monolayer. Therewere only a few reports dealing with the direct observation of domain structures in
文摘Morphology of dipalmitoyl phosphatidyl choline (DPPC)-cholesterol (Chol) mixed monolayer formed on water surface by dropping method was investigated using surface tension measurement (STm), Brewster angle microscopy (BAM), and fluorescence microscopy (FM). STm showed strong condensation effect of Chol in fluidic DPPC monolayer. Excess area (S<sub>ex</sub>) from mean mixing state of DPPC and Chol was about twice larger than that by general compression method in the range from xC = 0.2 to 0.4 (xC: mole fraction of Chol). BAM and FM images showed clearly that the fluidic DPPC monolayer changed to condensed rigid monolayer due to the condensation effect of Chol. At more than xC = 0.3 DPPC-Chol mixed monolayer changed to condensed state similar to the Chol monolayer. These results support previous reports by compression method that Chol molecule demonstrates the strong condensation effect to the fluidic monolayer and also indicate that dropping method enables to form unique monolayer on the water surface.
基金the National Natural Science Foundation of China.
文摘Two-dimensional domain structures are normally formed at the air-water interface due to phase separation in mixed monolayers, in which their components are incompletely miscible. This provides us a chance for studying some quasi-two-dimensional phenomena in physics, such as phase separation and phase transition. On the other hand, mixed monolayers provide us a way of assembling several kinds of functional molecules into
