• Bulletin of the Korean Chemical Society
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• v.31 no.11
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• pp.3195-3200
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• 2010

We have performed molecular dynamics simulations of atomistic models of $C_{60}$ molecules and DMPC bilayer membranes to study the static and dynamic effects of carbon nanoparticles on biological membranes. All four $C_{60}$-membrane systems were investigated representing dilute and concentrated solutions of $C_{60}$ residing either inside or outside the membrane. The concentrated $C_{60}$ molecules in water phase start forming an aggregated cluster. Due to its heavy mass, the cluster tends to adhere on the surface of the bilayer membrane, hindering both translational and rotational diffusion of individual $C_{60}$. On the other hand, once $C_{60}$ molecules accumulate inside the membrane, they are well dispersed in the central region of the bilayer membrane. Because of the homogeneous dispersion of $C_{60}$ inside the membrane, each leaflet is pushed away from the center, making the bilayer membrane thicker. This thickening of the membrane provides more room for both translational and rotational motions of $C_{60}$ inside the membrane compared to that in the water region. As a result, the dynamics of $C_{60}$ inside the membrane becomes faster with increasing its concentration.

• Journal of the Korean Society of Food Science and Nutrition
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• v.22 no.3
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• pp.323-327
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• 1993

The effect of soyasaponin on the liposomal phospholipid membrane was investigated by differential scanning calorimetry (DSC). Soyasaponins were obtained and the enthalpy changes and the sizes of cooperative unit of the transition were calculated. The thermograms of L-$\alpha$-dimyristoyl phosphatidylcholine (DMPC) incorporated with soyasaponin showed that the phase transition temperature was significantly lowered and the peak was broadened. This was attributed to the possibility that incorporation of soyasaponin into the lipid bilayers reduced the cooperative unit of phospholipid bilayers. These results indicate soyasaponin might have significant effect on the fluidity of biological membrane.

• The Korean Journal of Pharmacology
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• v.24 no.1
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• pp.43-52
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• 1988

To elucidate the mechanism of action of local anesthetics, the effects of local anethetics on the microenvironment of the lipid bilayers of synaptosomal plasma membrane vesicles (SPMV) isolated from bovine brain and dimyristoylphosphatidylcholine (DMPC) multilamellar liposomes were investigated employing the intermolecular excimer fluorescence technique and differential scanning calorimetry (DSC). The relative intensities of excimer and monomer fluorescence of pyrene are a simple linear function of the viscosity of a homologous series of solvents. The microviscosity(${\eta}$)of the hydrocarbon region of SPMV was measured by this method and the value was $57.3{\pm}5.3\;cP$ at $37^{\circ}C$. In the presence of lidocaine-HCl and procaine-HCl, the values decreased to $46.5{\pm}5.1\;cP$ and $54.7{\pm}4.8\;cP$, respectvely. The differential scanning thermograms of DMPC multilamellar liposomes showed that local anesthetics significantly lowered the phase transition temperature, broadened the thermogram peaks, and reduced the size of the cooperative unit. These results indicate that local anesthetics have significant fluidizing effects on biomembranes and perturbation of membrane lipids may produce some, but not all, of their pharmacological actions.

• BMB Reports
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• v.30 no.4
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• pp.240-245
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• 1997

Interactions between ganglioside $G_{M3}$ and glucose transporter, GLUT1 were studied by measuring the effect of $G_{M3}$ on steady-state and time-resolved fluorescence of purified GLUT1 in synthetic lipids and on the 3-O-methylglucose uptake by human erythrocytes. The intrinsic tryptophan fluorescence showed a GLUT 1 emission maximum of 335 nm, and increased in the presence of $G_{M3}$ by 12% without shifting the emission maximum, The fluorescence lifetimes of intrinsic tryptophan on GLUT1 consisted of a long component of 7.8 ns and a short component of 2,3 ns and $G_{M3}$ increased both lifetime components. Lifetime components were quenched by acrylamide and KI. Acrylarnide-mduced quenching of long-lifetime components was partly recovered by $G_{M3}$ However. KI-induccd quenching of short- and long-lifetime components was not rescued by $G_{M3}$. The anisotropy of 1.6-diphenyl-1.3.5-hexatriene (DPH)-probed dimyristoylphosphatidylcholine (DMPC) model membrane was also increased with $G_{M3}$ incorporation, The transport rate of 3-O-methylglucose increased by 20% with $G_{M3}$ incorporation on the erythrocytes, Therefore, $G_{M3}$ altered the environment of lipid membrane and induced the conformational change of GLUT1.

• Electrical & Electronic Materials
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• v.9 no.5
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• pp.450-454
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• 1996

Maxwell-Displacement-Current(MDC) measuring technique has been applied to the study of monolayers of Dilauroylphosphatidylcholine (L-.alpha.-DLPC) and Dimyristoylphosphatidylcholine (L-.alpha.-DMPC). The displacement current was generated from monolayers on a water surface by monolayer compression. Displacement current was generated when the area per molecule was about 250.angs.$^{2}$, 280.angs.$^{2}$. Displacement current was generated in the gas state, gas/liquid state, and liquid state in the course of monolayer compression. The orientational change of molecules in monolayers was discussed on the basis of the MDCs obtained. Finally, we measured differential thermal analysis of sample.

• Journal of Pharmaceutical Investigation
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• v.41 no.4
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• pp.205-210
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• 2011

Genistein (GT), a major isoflavone found in soybeans, has a potent antioxidant effect that protects the skin from UV-induced damages and malignant melanoma. In order to enhance the cellular uptake of GT, liposome/Tat complexes were prepared by an electrostatic interaction of anionic liposome (DMPC/DCP, 9:1 in molar ratio) with Tat peptide (0.02 to 0.08 mole), one of the well-known cell penetrating peptide (CPP). As the amount of Tat increased, the size increased but the zeta potential decreased. In vitro release study with dialysis membrane elicited GT release from liposomal preparations in a controlled manner. The addition of Tat increased GT release, especially for the initial period. In the cellular uptake study by incubating B16 melanoma cells with various liposomal preparations containing GT, B16 melanoma cells demonstrated a time-dependent increase of drug accumulation. Compared to the aqueous GT suspension, intracellular uptake was substantially enhanced by anionic liposomal formulation and further increased by the complex formulation. Therefore, liposome/ Tat complex might be a good candidate for facilitating intracellular drug delivery.