Effects of poly (ethylene glycol) chains conformational transition on the properties of mixed DMPC/DMPE-PEG thin liquid films and monolayers

Georgiev, Georgi; Sarker, Dipak K.; Al-Hanbali, Othman; Lalchev, Zdravko

doi:10.1016/j.colsurfb.2007.05.006

Cited by 34 publications

(30 citation statements)

References 27 publications

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“…The difference in the release of resveratrol from the PEGylated liposomes in PBS and simulated saliva medium could arise due to differences in the conformation of the PEG chains in both systems. Though the mushroom-to-brush transitions of PEG chains have been generally attributed to the amount of PEG chains on the liposomal surface, other factors such as the surface charges and the packing parameter of the lipid bilayer have also been identified to influence the conformational transitions of the PEG chains [49]. The difference in the phosphate buffered saline and simulated saliva medium is in their pH and ion composition, which in turn can alter the hydration layer around the polar head groups and consequently affect the packing parameters of liposomal bilayer [50–52].…”

Section: Resultsmentioning

confidence: 99%

Novel Resveratrol and 5-Fluorouracil Coencapsulated in PEGylated Nanoliposomes Improve Chemotherapeutic Efficacy of Combination against Head and Neck Squamous Cell Carcinoma

Mohan

Narayanan

Sethuraman

et al. 2014

BioMed Research International

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Increasing consumption of tobacco and alcohol has led to a steady increase in the incidence of head and neck cancers in Asia. The drawbacks associated with the existing chemotherapeutic and surgical interventions have necessitated the development of a safer alternative for therapy of head and neck cancers. In this study we have explored the synergistic therapeutic potential of a phytochemical and chemotherapeutic agent using PEGylated liposomes as a delivery vehicle. Resveratrol and 5-fluorouracil were successfully coencapsulated in a single PEGylated nanoliposome. The thermal analysis and the nuclear magnetic resonance results revealed that resveratrol localized near the glycerol backbone of the liposomal membrane while 5-fluorouracil localized closer to the phosphate moiety, which influenced the release kinetics of both drugs. The nanoformulation was tested in vitro on a head and neck cancer cell line NT8e and was found to exhibit a GI50 similar to that of free 5-fluorouracil. Further, gene expression studies showed that the combination of resveratrol and 5-fluorouracil exhibited different effects on different genes that may influence the net antagonistic effect. The coencapsulation of resveratrol and 5-fluorouracil in a liposomal nanocarrier improved the cytotoxicity in comparison with the free drug combination when tested in vitro.

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Section: Resultsmentioning

confidence: 99%

Novel Resveratrol and 5-Fluorouracil Coencapsulated in PEGylated Nanoliposomes Improve Chemotherapeutic Efficacy of Combination against Head and Neck Squamous Cell Carcinoma

Mohan

Narayanan

Sethuraman

et al. 2014

BioMed Research International

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“…Studies have shown that at low PEG density, the PEG units on a surface are organized in a so-called mushroom configuration, which transforms to a brush configuration at higher PEG density. 20 In the mushroom regime, no lateral interaction between neighboring polymers occurs, implying that the nanoparticle surface is not completely covered with PEG. In the brush regime the polymers overlap, fully covering the surface and providing optimal surface protection against opsonization.…”

mentioning

confidence: 99%

The Effect of Nanoparticle Polyethylene Glycol Surface Density on Ligand-Directed Tumor Targeting Studiedin Vivoby Dual Modality Imaging

Hak¹,

Helgesen²,

Hektoen³

et al. 2012

ACS Nano

187

168

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The development and application of nanoparticles as in vivo delivery vehicles for therapeutic and/or diagnostic agents has seen a drastic growth over the last decades. Novel imaging techniques allow real-time in vivo study of nanoparticle accumulation kinetics at the level of the cell and targeted tissue. Successful intravenous application of such nanocarriers requires a hydrophilic particle surface coating, of which polyethylene glycol (PEG) has become the most widely studied and applied. In the current study, the effect of nanoparticle PEG surface density on the targeting efficiency of ligand-functionalized nanoemulsions was investigated. We synthesized 100 nm nanoemulsions with a PEG surface density varying from 5 to 50 mol%. Fluorescent and paramagnetic lipids were included to allow their multimodal detection, while RGD peptides were conjugated to the PEG coating to obtain specificity for the αvβ3-integrin. The development of a unique experimental imaging setup allowed us to study, in real time, nanoparticle accumulation kinetics at (sub)-cellular resolution in tumors that were grown in a window chamber model with confocal microscopy imaging, and at the macroscopic tumor level in subcutaneously grown xenografts with magnetic resonance imaging. Accumulation in the tumor occurred more rapidly for the targeted nanoemulsions than for the non-targeted versions, and the PEG surface density had a strong effect on nanoparticle targeting efficiency. Counter intuitively, yet consistent with the PEG density conformation models, the highest specificity and targeting efficiency was observed at a low PEG surface density.

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“…This is quite clear because PEG is known to remove water from the hydration shell of the phosphatidylcholine membranes. This results in a reduction of the effective size of the “hydrated” lipid head groups and in the enhanced lateral packing of the membrane lipids (formation of an ordered state) . This change in microenvironment forces the molecules to adopt a different self‐assembly mode with a face‐to‐face alignment.…”

Section: Resultsmentioning

confidence: 99%

Highly Responsive Fluorescent Assemblies Allow for Unique, Multiparametric Sensing of the Phospholipid Membrane Environment

Gulyani

Dey

Bhattacharya

2018

Chemistry A European J

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Despite decades-long extensive research, probes that provide a comprehensive description of the lipid membrane microenvironment are still lacking. We report here a 'smart' pyrene-terpyridine probe for multiparametric sensing of lipid membranes; wherein the complexity of the local microenvironment can be described by distinct features of the probe fluorescence. The self-assembly of the probe molecules in phospholipid bilayers is sensitive to membrane order and phase state. The self-assembled probes show a unique emission, influenced by dye-dye interactions and excited state charge transfer. Moreover, this emission is sensitive to interfacial hydration, with very specific changes in emission wavelengths and fluorescence lifetimes as lipid compositions and properties are varied. In parallel, changes in lipid order along with hydration affect the ground state interactions in dye-aggregates and thus can be measured through ratiometric changes in excitation and emission readouts. In addition, fluorescence anisotropy measurements provide another way to study the nature of dye-aggregates in lipid bilayers. Overall, here we demonstrate how multiple aspects of membrane microenvironment can be sensed through unique fluorescence signatures of this ҆smart҆ probe in lipid membranes, and establish a new paradigm in lipid membrane sensing.

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Effects of poly (ethylene glycol) chains conformational transition on the properties of mixed DMPC/DMPE-PEG thin liquid films and monolayers

Cited by 34 publications

References 27 publications

Novel Resveratrol and 5-Fluorouracil Coencapsulated in PEGylated Nanoliposomes Improve Chemotherapeutic Efficacy of Combination against Head and Neck Squamous Cell Carcinoma

Novel Resveratrol and 5-Fluorouracil Coencapsulated in PEGylated Nanoliposomes Improve Chemotherapeutic Efficacy of Combination against Head and Neck Squamous Cell Carcinoma

The Effect of Nanoparticle Polyethylene Glycol Surface Density on Ligand-Directed Tumor Targeting Studiedin Vivoby Dual Modality Imaging

Highly Responsive Fluorescent Assemblies Allow for Unique, Multiparametric Sensing of the Phospholipid Membrane Environment

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