A Closer Look at the Structure of Sterically Stabilized Liposomes: A Small-Angle X-ray Scattering Study

Varga, Zoltán; Berényi, Szilvia; Szokol, Bálint; Őrfi, László; Kéri, Gÿorgý; Peták, István; Hoell, Armin; Bóta, Attila

doi:10.1021/jp9109207

Cited by 29 publications

(25 citation statements)

References 25 publications

(39 reference statements)

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“…Upon adding DPPC to the system (samples N3 and N4) however, a well expressed, broad peak appears in the scattering curve in the interval from 0.8 to 2 nm -1 , which corresponds to the squared form factor of a single phospholipid bilayer in a unilamellar vesicle [29][30][31]. Its appearance is squarely indicative of the presence of lipid bilayers, thus the dominant structural features are due to the extra DPPC molecules.…”

Section: Small-angle X-ray Scatteringmentioning

confidence: 99%

“…By employing a shell model of spherical symmetry, an approximate description of the layer structure becomes feasible in terms of the radial electron density distribution. Neglecting the interactions between individual nanoerythrosomes and assuming spherical symmetry, the scattering intensity can be calculated by the symmetric '2 Gaussian' model [31][32][33][34]. Here one pair of Gaussian functions represent the variation of electron density orthogonal to the bilayer surface due to the polar head group regions, while another pair describes the protein molecules located in the bilayer and at its both surfaces.…”

Section: Small-angle X-ray Scatteringmentioning

confidence: 99%

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Physicochemical characterization of artificial nanoerythrosomes derived from erythrocyte ghost membranes

Deák

Mihály

Szigyártó

et al. 2015

Colloids and Surfaces B: Biointerfaces

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Colloidal stabile nanoerythrosomes with 200 nm average diameter were formed from hemoglobin-free erythrocyte ghost membrane via sonication and membrane extrusion. The incorporation of extra lipid (1,2-dipalmitoyl-sn-glycero-3-phosphocholine, DPPC), added to the sonicated ghosts, caused significant changes in the thermotropic character of the original membranes. As a result of the increased DPPC ratio the chain melting of the hydrated DPPC system and the characteristic small angle X-ray scattering (SAXS) of the lipid bilayers appeared. Significant morphological changes were followed by transmission electron microscopy combined with freeze fracture method (FF-TEM). After the ultrasonic treatment the large entities of erythrocyte ghosts transformed into nearly spherical nanoerythrosomes with diameters between 100-300 nm and at the same time a great number of 10-30 nm large membrane proteins or protein clusters were dispersed in the aqueous medium. The infrared spectroscopy (FT-IR) pointed out, that the sonication did not cause changes in the secondary structures of the membrane proteins under our preparation conditions. About fivefold of extra lipid -compared to the lipid content of the original membrane -caused homogeneous dispersion of nanoerythrosomes however the shape of the vesicles was not uniform. After the addition of about tenfold of DPPC, monoform and monodisperse nanoerythrosomes became typical. The outer surfaces of these roughly spherical objects were frequently polygonal, consisting of a net of pentagons and hexagons..

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Section: Small-angle X-ray Scatteringmentioning

confidence: 99%

Section: Small-angle X-ray Scatteringmentioning

confidence: 99%

Physicochemical characterization of artificial nanoerythrosomes derived from erythrocyte ghost membranes

Deák

Mihály

Szigyártó

et al. 2015

Colloids and Surfaces B: Biointerfaces

Self Cite

View full text Add to dashboard Cite

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“…In order to describe the electron density (ED) profile along the normal of the phospholipid bilayer, we applied a Gaussian model (Brzustowicz and Brunger 2005;Varga et al, 2010). Briefly, the ED is described by the sum of Gaussian functions, hence the scattered intensity as the function of the scattering variable, , where is half the scattering angle and λ is the wavelength of the incident X-ray beam, reads ,…”

Section: Modell Fitting Proceduresmentioning

confidence: 99%

“…Recently, we applied SAXS to describe the bilayer structure of an SSL system (Varga et al, 2010) based on the Gaussian model of Brzustowicz and Brunger (2005). A different approach was applied by Arleth and Vermehren for the interpretation of SANS data on different SSLs (Arleth and Vermehren, 2010).…”

Section: Introductionmentioning

confidence: 99%

Characterization of the PEG layer of sterically stabilized liposomes: a SAXS study

Varga

Wacha

Vainio

et al. 2012

Chemistry and Physics of Lipids

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Synchrotron small-angle X-ray scattering analysis of the bilayer structure of a pharmacologically relevant sterically stabilized liposome system is presented. Describing the electron density profile of the bilayer with the superposition of Gaussian functions, the contribution of the poly(ethylene glycol) (PEG) layers to the total electron density was identified. The changes in the thickness of the PEG layer as well as the distribution of the PEG chains among the outer and inner leaflets of the bilayers were followed by changing the molar ratio of the PEG-lipid and the molar weight of the PEG molecule.

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“…A similar approach was used recently for the localization of epidermal growth factor receptor tyrosine kinase inhibitor drug in a PEGylated liposome (POPC) [40]. Bóta et al [41] have used multilamellar vesicles as reactor of nanoparticles.…”

Section: Microstructure Characterizationmentioning

confidence: 99%

Anomalous small-angle X-ray scattering from charged soft matter

Sztucki

Cola

Narayanan

2012

Eur. Phys. J. Spec. Top.

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Abstract. A review of recent applications of Anomalous Small-Angle X-ray Scattering (ASAXS) to charged soft matter systems is presented. Although the potential of ASAXS was realized in the eighties [1], applications to soft matter systems became feasible in recent years thanks to the technical developments at the synchrotron sources. Examples include both stiff chain and flexible polyelectrolytes, colloidal brush-like polyelectrolytes, DNA, RNA, and polysaccharides where the counterion profile could be determined with high precision and compared with theoretical models. In addition, ASAXS has also been found useful for microstructure characterization in soft materials. Finally, the present capability for ASAXS studies is illustrated by an example involving a surfactant micellar system.

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A Closer Look at the Structure of Sterically Stabilized Liposomes: A Small-Angle X-ray Scattering Study

Cited by 29 publications

References 25 publications

Physicochemical characterization of artificial nanoerythrosomes derived from erythrocyte ghost membranes

Physicochemical characterization of artificial nanoerythrosomes derived from erythrocyte ghost membranes

Characterization of the PEG layer of sterically stabilized liposomes: a SAXS study

Anomalous small-angle X-ray scattering from charged soft matter

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