• Journal of Pharmaceutical Investigation
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• 제23권2호
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• pp.89-95
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• 1993

Polymerized vesicles were prepared from the monomeric cholesterol-containing surfactant. Spacer groups were introduced into [(cholesteryloxy)carbonylmethyl] [2-(methacryloyloxy)ethyl]dimethylammonium chloride (CHODAMA). In case of introducing the spacer groups to the cholesterol moiety, both permeability of vesicles and that of polymerized vesicles were decreased. In case of introducing the spacer groups to monomeric moiety, permeability of vesicles was increased, while that of polymerized vesicles was decreased.

• Journal of Pharmaceutical Investigation
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• 제22권2호
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• pp.115-124
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• 1992

The characteristics and stabilities of phosphatidylcholine liposomes covalently coupled with immunoglobulin fragments prepared by the REV method were investigated by the dynamic light scattering, absorbance and calcein release. Using a sulfhydryl-reactive phospholipid derivative of N-[4$({\rho}-maleimido-phenyl)$ butyl] phosphatidylethanolamine (MPB-PE), Fab' antibody fragments were covalently combined with preformed large unilamellar vesicles (LUV), Coupling ratio was $250\;{\mu}g$ of $Fab'/{\mu}mol$ of phospholipid in vesicles, From dynamic light scattering, it was found that the size of the vesicles increases as the ratio of cholesterol to lipid increases, but that apparently, the size of liposomes was not sensitive to the existence of Fab' fragments. Regardless of inserting Fab' fragments, the absorbance of liposomes decreased as the amounts of bile salt (BS) added. At very low BS concentrations, BS/lipid aggregates would be formed in the outer vesicles monolayer, while, at the high BS concentrations, mixed micelles would be preferred. The vesicles incorporated with Fab' fragments, however, are more resistant to the bile salts than the MPB-PE vesicle are. The absorbance of vacant liposomes and calcein release resulted in that the Fab' vesicles and MPB-PE vesicles by the REV method are very stable, but that those by the sonication method sufferred the significant change of turbidities.

• 대한의생명과학회지
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• 제18권4호
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• pp.329-337
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• 2012

${\alpha}$-synuclein (${\alpha}$-syn) is known to be implicated in the pathogenesis of Parkinson's disease and transiently bind to biological vesicles. In this study, we examined the effect of molecular crowding on the interaction of ${\alpha}$-syn with biological vesicles by using inert polymers since the environment of proteins in cells are crowded with other macromolecules. The addition of different polymers including polyethylene glycol, dextran, and ficoll enhanced the binding of ${\alpha}$-syn to vesicles in a concentration-dependent manner and the association of ${\alpha}$-syn with vesicle was proportionally augmented by increased expression of ${\alpha}$-syn. However, molecular crowding had a neglectable effect on the vesicle binding of ${\alpha}$-syn mutants (A30P, TG6), which has been reported to show impaired vesicle binding capacity. These results suggest that transient interaction of ${\alpha}$-syn with vesicles occurs more commonly in cells than expected implying interaction with vesicles may be one of the physiological processes in which ${\alpha}$-syn is involved.

• Korean Chemical Engineering Research
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• 제49권4호
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• pp.400-404
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• 2011

폴리다이아세틸렌(polydiacetylene: PDA)은 독특한 광학적 특성, 즉 외부자극에 의하여 파란색에서 빨간색으로 색상이 변화하는 동시에 형광이 없던 상태에서 자가형광을 발현하는 특성 때문에 화학, 바이오센서로써 응용하기 위한 많은 연구들이 진행되어 왔다. 특히, 센서의 성능에서 감지하고자 하는 물질에 대한 우수한 민감도는 매우 중요하다. 본 연구에서는 다양한 필터 사이즈를 이용하여 10,12-pentacosadynoic acid(PCDA) 베시클의 크기를 조절함과 동시에 중합온도를 조절하여 ${\alpha}$-사이클로텍스트린(CD)을 검출하여 두 가지 효과가 민감도 향상에 어떤 영향을 미치는지 조사하였다. 필터를 사용하지 않은 베시클과 0.22 ${\mu}m$로 필터한 베시클을 $25^{\circ}C$에서 고분자한 후에 ${\alpha}$-CD(5 mM)와 30분 반응하였을 때 색전이 정도(colorimetric response, CR)가 31.4%에서 74.0%로 증가하였다. 또한, 0.22 ${\mu}m$로 필터한 베시클을 $25^{\circ}C$와 $5^{\circ}C$에서 고분자한 후에 ${\alpha}$-CD(5 mM)와 30분 반응하였을 때 CR값이 74.0%에서 99.2%로 증가하였다. 이는 폴리다이아세틸렌의 크기와 고분자시 온도를 조절함으로써 민감도를 크게 증가시킬 수 있음을 보여준다. 또한, 폴리다이이아세틸렌은 감도 향상이 매우 중요한 바이오물질을 검출하는데 적용될 수 있을 것이다.

• Bulletin of the Korean Chemical Society
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• 제28권4호
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• pp.667-674
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• 2007

Phase behavior for the mixed aqueous surfactant systems of cationic octadecyl trimethyl ammonium chloride (OTAC)/anionic ammonium dodecyl sulfate (ADS)/water was examined. Below the total surfactant concentrations of 1.5 m molal, mixed micelles were formed. At the total surfactant concentrations higher than 1.5 m molal, there appeared a region where mixed micelles and vesicles coexist. As the surfactant concentration increased, the systems looked very turbid and much more vesicles were observed. The vesicles were spontaneously formed in this system and their existence was observed by negative-staining transmission electron microscopy (TEM), small-angle neutron scattering (SANS) and encapsulation efficiency of dye. The vesicle region was where the molar fraction α of ADS to the total mixed surfactant was from 0.1 to 0.7 and the total surfactant concentration was above 5 × 10-4 molality. The size and structure of the vesicles were determined from the TEM microphotographs and the SANS data. Their diameter ranged from 450 nm to 120μm and decreased with increasing total surfactant concentration. The lamellar thickness also decreased from 15 nm to 5 nm with increasing surfactant concentration and this may be responsible for the decrease in vesicle size with the surfactant concentration. The stability of vesicles was examined by UV spectroscopy and zeta potentiometry. The vesicles displayed long-term stability, as UV absorbance spectra remained unchanged over two months. The zeta potentials of the vesicles were large in magnitude (40-70 mV) and the observed longterm stability of the vesicles may be attributed to such high ζ potentials.

• Applied Microscopy
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• 제47권3호
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• pp.165-170
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• 2017

Gas vesicles are intracellular gas-filled protein-shelled nanocompartments. The structures are spindle or cylinder-shaped, and typically $0.1{\sim}2{\mu}m$ in length and 45~250 nm in width. A variety of prokaryotes including photosynthetic bacteria and halophilic archaea form gas vesicles in their cytoplasm. Gas vesicles provide cell buoyancy as flotation devices in aqueous habitats. They are used as nanoscale molecular reporters for ultrasound imaging for biomedical purposes. The structures in halophilic archaea are poorly resolved due to the low signal-to-noise ratio from the high salt concentration in the medium. Such a limitation can be overcome using focused ion beam-thinning or inelastically scattered electrons. As the concentric bodies (~200 nm in diameter) in fungi possess gas-filled cores, it is possible that the concept of gas vesicles could be applied to eukaryotic microbes beyond prokaryotes.

• 분석과학
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• 제30권2호
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• pp.89-95
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• 2017

The thermodynamic functions for the binding of the peptide Substance P (SP) on the surface of lipid vesicles made of various types of lipids were obtained by using isothermal titration calorimetry. The reaction enthalpies measured from the experiments were -0.11 to $-4.5kcal\;mol^{-1}$. The sizes of the lipid vesicles were measured with dynamic light scattering instrument in order to get the correlation between the reaction enthalpies and the vesicle sizes. The bindings of SP on the lipid vesicles with diameter of 37 to 108 nm were classified into the enthalpy-driven reaction or the entropy-driven reaction according to the size of the lipid vesicles. For the enthalpy-driven binding reaction, the significance of the electrostatic interactions between SP and lipid molecules was affirmed from the experimental results of the DMPC/DMPG/DMPH and DMPC/DMPS/DMPH vesicles as well as the importance of the hydrophobic interactions between hydrophobic groups of SP and lipid molecules.

• Bulletin of the Korean Chemical Society
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• 제29권10호
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• pp.2005-2008
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• 2008

A cyclotetraphosphazene derivative with eight chains was synthesized from octachlorocyclotetraphosphazene. The vesicles were prepared using the cyclotetraphosphazene derivative and cholesterol. The resulting vesicles were characterized by TEM and measurements of their encapsulation efficiency. The stability of the vesicles was enhanced with the addition of dihexadecylphosphate. The size and the encapsulation efficiency of the vesicles changed according to the amount of cholesterol added. The size and the encapsulation efficiency of the vesicle were lowest when the mole ratio (cholesterol: the cyclophosphazene derivative) was 0.9.

• 대한화학회지
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• 제64권3호
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• pp.145-152
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• 2020

Flip-flop rate constants were measured by dithionite assay of NBD-PE fluorescence in DMPC/POPC vesicles made of various DMPC/POPC ratios. The activation energy, enthalpy, entropy, and free energy were determined based on the transition state theory. We found that the activation energy, enthalpy, and entropy increased as the amount of POPC increased, but the activation free energy was almost constant. These experimental results and other similar studies allow us to propose that the POPC molecules included in DMPC vesicles affect the flip-flop motion of NBD-PE in DMPC/POPC vesicles via increasing the packing order of the ground state of the bilayer of the vesicles. The increase in the packing order in the ground state seems to be a result of the effect of the overall molecular shape of POPC with a monounsaturated tail group, rather than the effect of the longer tail group.

• Psychiatry investigation
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• 제15권11호
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• pp.1011-1018
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• 2018

The analysis of extracellular vesicles has been accelerated because of the technological advancements in omics methods in recent decades. Extracellular vesicles provide multifaceted information regarding the functional status of the cells. This information would be critical in case of central nervous system cells, which are confined in a relatively sealed biological compartment. This obstacle is more dramatic in psychiatric disorders since their diagnosis primarily depend on the symptoms and signs of the patients. In this paper, we reviewed this rapidly advancing field by discussing definition of extracellular vesicles, their biogenesis and potential use as clinical biomarkers. Then we focused on their potential use in psychiatric disorders in the context of diagnosis and treatment of these disorders. Finally, we tried to combine the RDoC (Research Domain Criteria) with the use of extracellular vesicles in psychiatry research and practice. This review may offer new insights in both basic and translational research focusing on psychiatric disorders.