Mutual diffusion in aqueous solution of poly(ethyleneglycol) samples. Some comments on the effect of chain length and polydispersity

Vergara, Alessandro; Paduano, Luigi; Vitagliano, Vincenzo; Sartorio, Roberto

doi:10.1039/a906197e

Cited by 49 publications

(94 citation statements)

References 30 publications

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“…In fact according to the crystallographic data, the length of the PEG 2000 , present in the shell, should be around 30 , [25] that is, quite larger than the polar heads exposed by (C18) 2 DTPAGlu monomers on the hydrophilic shell (~20 ). The same arguments hold in the case of rod-like micelles whose radius is~40 and length is above 700 .…”

Section: Resultsmentioning

confidence: 98%

Peptide‐Containing Aggregates as Selective Nanocarriers for Therapeutics

et al. 2008

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New nanocarriers are obtained by assembling two amphiphilic monomers: one containing the bioactive peptide CCK8 spaced, by a polydisperse poly(ethylene glycol), from two hydrophobic tails ((C18)2PEG2000CCK8), and the other containing a chelating agent able to give stable radiolabeled indium-111 complexes linked to the same hydrophobic moiety ((C18)2DTPAGlu). The size and shape of the supramolecular aggregates were structurally characterized by dynamic light scattering, small-angle neutron scattering, and cryogenic transmission electronic microscopy. Under the experimental conditions we investigated (pH 7.4 and molar ratio between monomers 30:70), there is the presence of high polydisperse aggregates: rod-like micelles with a radius of approximately 40 A and length >700 A, open bilayer fragments with thickness approximately 65 A, and probably vesicles. The presence of the bioactive peptide well exposed on the external surface of the aggregate allows selective targeting of nanocarriers towards the cholecystokinin receptors overexpressed by the cancerous cells. In vitro binding assays and in vivo biodistribution studies by nuclear medicine experiments using indium-111 are reported. Moreover, preliminary data concerning the drug loading capability of the aggregates and their drug efficiency on the target cells is reported by using the cytotoxic drug doxorubicin. Incubation of receptor-positive and control cells with peptide-containing aggregates filled with doxorubicin shows significantly lower cell survival in receptor-expressing cells relative to the control, for samples incubated in the presence of doxorubicin.

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Section: Resultsmentioning

confidence: 98%

Peptide‐Containing Aggregates as Selective Nanocarriers for Therapeutics

et al. 2008

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“…It has been demonstrated that the diffusion coefficient of water within a PEG coating is slower than in bulk water. 41 …”

Section: Resultsmentioning

confidence: 99%

Ultrasmall, Water-Soluble Magnetite Nanoparticles with High Relaxivity for Magnetic Resonance Imaging

et al. 2009

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Ultrasmall (3, 4, 5, and 6 nm), water-soluble Fe3O4 magnetic nanoparticles were synthesized in diethylene glycol (DEG) via a facile one-pot reaction. Hydrodynamic size and relaxation time measurements did not show particle aggregation when Fe3O4 nanoparticles were dispersed in phosphate buffered saline, fetal bovine serum, or calf bovine serum for 1 week. Furthermore, the new Fe3O4 nanoparticles tolerated high salt concentrations (≤1 M NaCl) and a wide pH range from 5 to 11. Surface modification of the nanoparticles with poly(ethylene glycol) bis(carboxymethyl) ether (HOOC-PEG-COOH, 600 g/mol) was accomplished through a ligand-exchange reaction. The effects of PEG modification on magnetization and relaxivity of the Fe3O4 nanoparticles were investigated, and the results indicate that the increase in transverse relaxivity after PEG modification may be due to the increased volume of slowly diffusing water surrounding each nanoparticle. In vitro experiments showed that the DEG- and PEG-coated Fe3O4 nanoparticles have little effect on NIH/3T3 cell viability.

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“…These differences can be attributed to a larger water-slow diffusion layer of PEG modified SPIONs. Measurements of water diffusion coefficients in solutions of PEG of varying molecular weights indicate that water moves more slowly in more highly concentrated PEG environments 72 . Protons in the slow water diffusion layer spend a longer period of time in close proximity to the magnetic field of the SPION core allowing for more efficient dephasing of the magnetic moments of neighboring protons.…”

Section: Important Spion Design Parametersmentioning

confidence: 99%

Magnetite nanoparticles for medical MR imaging

2011

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Nanotechnology has given scientists new tools for the development of advanced materials for the detection and diagnosis of disease. Iron oxide nanoparticles (SPIONs) in particular have been extensively investigated as novel magnetic resonance imaging (MRI) contrast agents due to a combination of favorable superparamagnetic properties, biodegradability, and surface properties of easy modification for improved in vivo kinetics and multifunctionality. This review discusses the basics of MR imaging, the origin of SPION’s unique magnetic properties, recent developments in MRI acquisition methods for detection of SPIONs, synthesis and post-synthesis processes that improve SPION’s imaging characteristics, and an outlook on the translational potential of SPIONs.

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Mutual diffusion in aqueous solution of poly(ethyleneglycol) samples. Some comments on the effect of chain length and polydispersity

Cited by 49 publications

References 30 publications

Peptide‐Containing Aggregates as Selective Nanocarriers for Therapeutics

Peptide‐Containing Aggregates as Selective Nanocarriers for Therapeutics

Ultrasmall, Water-Soluble Magnetite Nanoparticles with High Relaxivity for Magnetic Resonance Imaging

Magnetite nanoparticles for medical MR imaging

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