• Bulletin of the Korean Chemical Society
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• v.31 no.8
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• pp.2190-2194
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• 2010

Development of the methods to organize zeolite microcrystals into closely packed and uniformly aligned monolayers on various substrates have been pursued viewing microparticles as a novel class of building blocks. We now report that the vertically aligned zeolite monolayer can be applied as novel supramolecularly organized systems for anisotropic photoluminescence in high dichroic ratio, to study energy transfer dynamics between the internal and external fluorophores, and to develop zeolite-based advanced materials. Study of polarized fluorescence spectroscopy and angle-dependent intensity change with dye molecules in different surroundings further provides insight into molecular interactions that can be used for the future design of optoelectronic device in nanometer size. In addition, this report shows that isolating of organic dye through surface treatment is crucial for preventing the egress of the incorporated dye molecules from the channels of zeolite to the solution and to enhance the anisotropic luminescence.

• Korean Journal of Materials Research
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• v.6 no.12
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• pp.1242-1247
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• 1996

Spatially fixed bichromophoric systems with nonidentical chromophores have been extensively employed for studies of electron transfer and excitation transfer. Excitation hopping behavior between two naphthy1 moieties on 7,14-dihydro-7,14-ethanodibenz[a,h] anthracene(DEA)has been explored by the time-resolved fluorescence anisotropy measurements. The experimentally obtained value of the hopping rate in DEA agrees at least qualitatively with that calculated on the basis of the Dexter's theory, but disagrees with that calculated on the basis of the Forster's theory, indicates that for a pair of donor and acceptor with inter-chromophore separation as short as 4.5 $\AA$, excitation transfer via electron exchange is a predominant process.

• The Korean Journal of Physiology and Pharmacology
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• v.4 no.5
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• pp.409-415
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• 2000

Fluorescence polarization of 1,6-diphenyl-1,3,5-hexatriene (DPH) was used to evaluate the effects of dopamine HCl on the range of the rotatioanl mobility of bulk bilayer structure of the synaptosomal plasma membrane vesicles (SPMV) isolated from whole bovine brain. In a dose-dependent manner, dopamine decreased the anisotropy $({\gamma}),$ limiting anisotropy $({\gamma}{infty})$ and order parameter (S) of DPH in the membranes. These indicate that dopamine increased the rotational mobility of the probe in the neuronal membranes. Cationic 1-[4-(trimethylammonio)-phenyl]-6-phenylhexa-1,3,5-hexatriene (TMA-DPH) and anionic 3-[p-(6-phenyl)-1,3,5-hexatrienyl]-phenylpropionic acid (PRO-DPH) were utilized to examine the range of transbilayer asymmetric rotational mobility of the neuronal membranes. Dopamine had a greater increasing effect on the mobility of the inner monolayer as compared to the outer monolayer of the neuronal membranes. It has been proven that dopamine exhibits a selective rather than nonselective fluidizing effect within the transbilayer domains of the SPMV.

• Korea-Australia Rheology Journal
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• v.14 no.3
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• pp.129-138
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• 2002

A cationic surfactant, cetyltrimethylammonium $\rho$-toluenesufonate (CTA$\rho$TS), forms long threadlike micelles in aqueous solution. The threadlike micelles make concentrated entanglement networks, so that the solution shows pronounced viscoelastic behavior as concentrated polymer systems do. However, a mechanism for a process responsible for the longest relaxation time of the threadlike micellar system is different from that of semi-dilute to concentrated polymer systems. The threadlike micellar system exhibits unique viscoelasticity described by a Maxwell model. The longest relaxation time of the threadlike micellar system is not a function of the concentration of CTA$\rho$TS, but changes with that of $\rho$-toluenesufonate ($\rho$$TS^{-}$) ions in the bulk aqueous phase supplied by adding sodium $\rho$-toluenesulfonate (NapTS). The rates of molecular motions in the threadlike micelles are not influenced by the concentration of $\rho$$TS^{-}$ anions, therefore, molecular motions in the threadlike micelles (micro-dynamics) are independent of the longest relaxation mechanism (macro-dynamics). A nonionic surfactant, oleyldimethylamineoxide (ODAO), forms long threadlike micelles in aqueous solution without any additives. The aqueous threadlike micellar system of ODAO also shows Maxwell type viscoelastic behavior. However, the relaxation mechanism for the longest relaxation process in the system should be different from that in the threadlike micellar systems of CTA$\rho$TS, since the system of ODAO does not contain additive anions. Because increase in the average degree of protonation of head groups of ODAO molecules in micelles due to adding hydrogen bromide causes the relaxation time remarkably longer, changes in micro-structure and micro-dynamics in the threadlike micelle are closely related to macro-dynamics in contrast with the threadlike micellar system of CTA$\rho$TS.

• International Journal of Oral Biology
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• v.35 no.4
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• pp.159-167
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• 2010

To provide a basis for studying the pharmacological actions of tetracaine HCl, we analyzed the membrane activities of this local anesthetic. The n-(9-anthroyloxy) stearic and palmitic acid (n-AS) probes (n = 2, 6, 9, 12 and 16) have been used previously to examine fluorescence polarization gradients. These probes can report the environment at a graded series of depths from the surface to the center of the membrane bilayer structure. In a dosedependent manner, tetracaine HCl decreased the anisotropies of 6-AS, 9-AS, 12-AS and 16-AP in the hydrocarbon interior of synaptosomal plasma membrane vesicles isolated from bovine cerebral cortex (SPMV), and liposomes derived from total lipids (SPMVTL) and phospholipids (SPMVPL) extracted from the SPMV. However, this compound increased the anisotropy of 2-AS at the membrane interface. The magnitude of the membrane rotational mobility reflects the carbon atom numbers of the phospholipids comprising SPMV, SPMVTL and SPMVPL and was in the order of the 16, 12, 9, 6, and 2 positions of the aliphatic chains. The sensitivity of the effects of tetracaine HCl on the rotational mobility of the hydrocarbon interior or surface region was dependent on the carbon atom numbers in the descending order 16-AP, 12-AS, 9-AS, 6-AS and 2-AS and on whether neuronal or model membranes were involved in the descending order SPMV, SPMVPL and SPMVTL.

• Biomedical Science Letters
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• v.23 no.1
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• pp.17-24
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• 2017

Estrogens are effective neuroprotectants in vivo and in vitro. To obtain a better insight into the molecular mechanisms of action of neuroprotection by $17{\beta}-estradiol$ (E2), we examined the differential effects of E2 on the fluidity of synaptosomal plasma membrane vesicles (SPMV) isolated from rat cerebral cortex. Intramolecular excimerization of 1,3-di(1-pyrenyl)-propane (Py-3-Py) was used to investigate the effects of E2 on the bulk and annular lateral diffusion of the SPMV. In addition, we examined the effects of E2 on the rotational diffusion of individual leaflet of SPMV exploiting selective quenching of outer monolayer 1,6-diphenyl-1,3,5-hexatriene (DPH) fluorescence by trinitrophenyl groups. The $F{\ddot{o}}rster$ distance $R_0$ value for the tryptophan-Py-3-Py donor-acceptor pair was $26.9{\AA}$. E2 increased the lateral mobility of both bulk and annular lipids in SPMV in a dose-dependent manner, but a larger effect on bulk lipids was observed. Although E2 decreased the anisotropy of DPH in SPMV, E2 had a greater fluidizing effect on the outer leaflet compared to the inner leaflet. These results suggest that E2 selectively fluidizes the more fluid regions within SPMV. It is highly probable that E2 mostly fluidizes the bulk lipids, away from either annular lipids or lipid rafts, in the outer leaflet of SPMV. This selective fluidization may be one of the nongenomic mechanisms of neuroprotection by E2.

• The Korean Journal of Physiology and Pharmacology
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• v.7 no.3
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• pp.119-124
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• 2003

To elucidate the molecular mechanism of pharmacological action of local anesthetics, we studied membrane actions of tetracaine, bupivacaine, lidocaine, prilocaine and procaine. Fluorescence polarization of n-(9-anthroyloxy)stearic acid (n-AS) was used to examine the effects of these local anesthetics on differential rotational mobility of different positions of the number of synaptosomal plasma membrane vesicle (SPMV) phospholipid carbon atoms. The four membrane components differed with respect to 3, 6, 9 and 16-(9-anthroyloxy)stearic acid (3-AS, 6-AS, 9-AS and 16-AP) probes, indicating that differences in the membrane fluidity might be present. Degrees of the rotational mobility of 3-AS, 6-AS, 9-AS and 16-AP were different depending on depth of hydrocarbon interior. In a dose-dependentmanner, tetracaine, bupivacaine, lidocaine, prilocaine and procaine decreased anisotropy of 3-AS, 6-AS, 9-AS and 16-AP in the hydrocarbon interior of the SPMV. These results indicate that local anesthetics have significant disordering effects on hydrocarbon interior of the SPMV, thus affecting the transport of $Na^+$ and $K^+$ in nerve membranes and leading to anesthetic action.

• Applied Chemistry for Engineering
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• v.35 no.3
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• pp.230-238
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• 2024

In the present work, the interaction of lipid-based zwitterionic surfactant CDP-W with the vesicle membrane of phospholipids was investigated. For this purpose, interfacial properties such as critical micelle concentration (CMC) and surface tension were measured for the zwitterionic surfactant CDP-W and lecithin S100-3. The zeta potential of 1 wt% aqueous surfactant solutions was also measured as a function of pH to determine the iso-electric point of CDP-W surfactant, where the characteristic of CDP-W surfactant changes from a cationic surfactant to an anionic surfactant. Based on the iso-electric point measurement of CDP-W surfactant, the effects of pH change and CDP-W addition on the stability of S100-3 liposome systems were studied, such as average particle size, polydispersity index (PDI), and zeta potential. The effect of CDP-W on the fluidity characteristics of liposome membranes such as fluorescence anisotropy ratio, deformability, and melting point was investigated at pH 6 where the most stable liposomes were prepared to understand the effect of the fluidity of the liposome membrane on the encapsulation efficiency of active materials and the stability of liposome systems.