Calorimetry and Cryo-Transmission Electron Microscopic Studies of PEG2000-Grafted Liposomes

Hashizaki, Kaname; Taguchi, Hiroyuki; Tsuchiya, Koji; Sakai, Hideki; Abe, Masahiko; Saito, Yoshihiro; Ogawa, Naotake

doi:10.1248/cpb.54.561

Cited by 15 publications

(8 citation statements)

References 18 publications

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“…It is possible to convert DSPE to a more hydrophilic surfactant by grafting a hydrophilic segment such as PEG . For instance, the increased hydrophilicity inflicts the formation of normal spherical micelles (L 1 phase) upon mixing DSPE-mPEG 2000 in water. , The contribution of grafting hydrophilic PEG to the molecular structure of the amphiphilic lipid DSPE is thus dominating.…”

Section: Resultsmentioning

confidence: 99%

PEGylation of Phytantriol-Based Lyotropic Liquid Crystalline Particles—The Effect of Lipid Composition, PEG Chain Length, and Temperature on the Internal Nanostructure

et al. 2014

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Poly(ethylene glycol)-grafted 1,2-distearoyl-sn-glycero-3-phosphoethanolamines (DSPE-mPEGs) are a family of amphiphilic lipopolymers attractive in formulating injectable long-circulating nanoparticulate drug formulations. In addition to long circulating liposomes, there is an interest in developing injectable long-circulating drug nanocarriers based on cubosomes and hexosomes by shielding and coating the dispersed particles enveloping well-defined internal nonlamellar liquid crystalline nanostructures with hydrophilic PEG segments. The present study attempts to shed light on the possible PEGylation of these lipidic nonlamellar liquid crystalline particles by using DSPE-mPEGs with three different block lengths of the hydrophilic PEG segment. The effects of lipid composition, PEG chain length, and temperature on the morphology and internal nanostructure of these self-assembled lipidic aqueous dispersions based on phytantriol (PHYT) were investigated by means of synchrotron small-angle X-ray scattering and Transmission Electron Cryo-Microscopy. The results suggest that the used lipopolymers are incorporated into the water-PHYT interfacial area and induce a significant effect on the internal nanostructures of the dispersed submicrometer-sized particles. The hydrophilic domains of the internal liquid crystalline nanostructures of these aqueous dispersions are functionalized, i.e., the hydrophilic nanochannels of the internal cubic Pn3m and Im3m phases are significantly enlarged in the presence of relatively small amounts of the used DSPE-mPEGs. It is evident that the partial replacement of PHYT by these PEGylated lipids could be an attractive approach for the surface modification of cubosomal and hexosomal particles. These PEGylated nanocarriers are particularly attractive in designing injectable cubosomal and hexosomal nanocarriers for loading drugs and/or imaging probes.

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Section: Resultsmentioning

confidence: 99%

PEGylation of Phytantriol-Based Lyotropic Liquid Crystalline Particles—The Effect of Lipid Composition, PEG Chain Length, and Temperature on the Internal Nanostructure

et al. 2014

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“…30,31 The DSC results showed that up to 10 mol% of 2 was completely coassembled into the ONTs without phase separation. In the DSC measurement ( Figure 7, Table S1), the mother ONT showed good thermal stability since no endothermic or exothermic peaks were found below 180°C.…”

Section: Dsc and Xrd Analysismentioning

confidence: 99%

Effects of PEGylation on the physicochemical properties and in vivo distribution of organic nanotubes

Ding¹,

Minamikawa²,

Kameta³

et al. 2014

IJN

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Application of organic nanotubes (ONTs) into drug nanocarriers ultimately requires validation in live animals. For improving the dispersibility in biological media and in vivo distribution, the outer surface of an ONT was functionalized with polyethylene glycol (PEG) via the coassembly of an ONT-forming lipid with 5–20 mol% of a PEG-tethered lipid analogue (PEG-lipid). Firstly, the effect of PEGylation on the psysicochemical properties of ONTs, such as morphology and dispersibility, was investigated. PEGylation of ONTs slightly reduced the average length and effectively prevented the aggregation in phosphate-buffered saline (PBS). The PEGylated ONTs even showed high thermal stability in aqueous dispersion at least up to 95°C. Secondly, differential scanning calorimetry and powder X-ray diffraction indicated that ~10 mol% of PEG-lipid was completely incorporated into the ONTs, while 20 mol% of PEG-lipid encountered a partial phase separation during coassembly. In the heating differential scanning calorimetry runs, the resultant PEGylated ONTs with 5 mol% PEG-lipid showed no sign of phase separation up to 180°C under lyophilized condition, while those with 10 mol% and 20 mol% PEG-lipid showed some phase separation of the PEG-lipid above 120°C. Finally, PEGylation significantly affected the tissue distribution and prolonged the persistence time in the blood in mice. Non-PEGylated ONTs was quickly cleared from the circulation after intravenous infusion and preferentially accumulated in the lung, while PEGylated ONTs was mainly trapped in the liver and could circulate in the blood up to 24 hours. This study provided valuable information of physicochemical properties and the in vivo distribution behavior of PEGylated ONTs for their potential application into drug nanocarriers.

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“…The sample drop was blotted with a filter paper to form a thin liquid film (<300 nm), and then it was frozen quickly in liquid ethane (<−170 • C). The resultant thin films of sample solution bridged on the cupper grid were observed directly by Hitachi H-7500 transmission electron microscopy [30].…”

Section: Cryogenic Transmission Electron Microscopy (Cryo-tem)mentioning

confidence: 99%

Structural and morphological transition of long-chain phospholipid vesicles induced by mixing with short-chain phospholipid

Takajo

Matsuki

Matsubara

et al. 2010

Colloids and Surfaces B: Biointerfaces

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Calorimetry and Cryo-Transmission Electron Microscopic Studies of PEG2000-Grafted Liposomes

Cited by 15 publications

References 18 publications

PEGylation of Phytantriol-Based Lyotropic Liquid Crystalline Particles—The Effect of Lipid Composition, PEG Chain Length, and Temperature on the Internal Nanostructure

PEGylation of Phytantriol-Based Lyotropic Liquid Crystalline Particles—The Effect of Lipid Composition, PEG Chain Length, and Temperature on the Internal Nanostructure

Effects of PEGylation on the physicochemical properties and in vivo distribution of organic nanotubes

Structural and morphological transition of long-chain phospholipid vesicles induced by mixing with short-chain phospholipid

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Calorimetry and Cryo-Transmission Electron Microscopic Studies of PEG2000-Grafted Liposomes

Cited by 15 publications

References 18 publications

PEGylation of Phytantriol-Based Lyotropic Liquid Crystalline Particles—The Effect of Lipid Composition, PEG Chain Length, and Temperature on the Internal Nanostructure

PEGylation of Phytantriol-Based Lyotropic Liquid Crystalline Particles—The Effect of Lipid Composition, PEG Chain Length, and Temperature on the Internal Nanostructure

Effects of PEGylation on the physicochemical properties and in vivo distribution of organic&nbsp;nanotubes

Structural and morphological transition of long-chain phospholipid vesicles induced by mixing with short-chain phospholipid

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Effects of PEGylation on the physicochemical properties and in vivo distribution of organic nanotubes