Synthesis, characterization, and biomedical applications of core–shell-type stimuli-responsive nanogels – Nanogel composed of poly[2-(N,N-diethylamino)ethyl methacrylate] core and PEG tethered chains

Oishi, Motoi; Nagasaki, Yukio

doi:10.1016/j.reactfunctpolym.2007.07.009

Cited by 60 publications

(38 citation statements)

References 106 publications

(110 reference statements)

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“…Utilizing this character, various environmentally sensitive polymeric materials have been developed. For example, the swelling/deswelling behavior of a PEGylated nanogel possessing a cross-linked PEAMA core can be controlled by the environmental pH [28,29]. In a previous study, we confirmed that RNP can disintegrate in response to low pH because the PMNT segment in PEG-b-PMNT possesses amino groups and a hydrophobic region in each repeating unit [21].…”

Section: Ph Response Of Hanpsupporting

confidence: 62%

Design and Preparation of a Nanoprobe for Imaging Inflammation Sites

Yoshitomi

Nagasaki

2012

Biointerphases

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To image inflammation sites, we developed a novel nanoparticle, hydroxylamine-containing nanoparticle (HANP), which emits an intense electron spin resonance (ESR)-signal triggered by enzymatic oxidation reaction and pH-sensitive self-disintegration. The nanoparticle was prepared from an amphiphilic block copolymer, poly (ethylene glycol)-b-poly[4-(2,2,6,6-tetramethylpiperidine-1-hydroxyl)aminomethylstyrene] (PEG-b-PMNT-H), which spontaneously forms a core-shell type polymeric micelle (particle diameter = ca. 50 nm) in aqueous media. Because the PMNT-H segment in the block copolymer possesses amino groups in each repeating unit, the particle can be disintegrated by protonation of the amino groups in an acidic pH environment such as inflammation sites, which is confined to the hydrophobic core of HANP.Mixing HANP with horseradish peroxidase (HRP)/H 2 O 2 mixture resulted in enzymatic oxidization of the hydroxylamines in the PEG-b-PMNT-H and converted the hydroxylamine to the stable nitroxide radical form in PEGb-poly[4-(2,2,6,6-tetramethylpiperidine-1-oxyl)aminomethylstyrene] (PEG-b-PMNT), which shows an intense ESR signal. It is interesting to note that the ESR signal increased at a greater rate under acidic conditions (pH 5.6) than that under neutral conditions (pH 7.4), although the enzymatic activity of HRP under neutral conditions is known to be much higher than that under acidic conditions. This indicates that enzymatic oxidation reaction was accelerated by synchronizing the disintegration of HANP under acidic conditions. On the basis of these results, HANP can be used as a high-performance ESR probe for imaging of inflammation sites.

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Section: Ph Response Of Hanpsupporting

confidence: 62%

Design and Preparation of a Nanoprobe for Imaging Inflammation Sites

Yoshitomi

Nagasaki

2012

Biointerphases

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“…1. This GNG has been reported to show extremely high dispersion stability and unique properties such as a reversible volume phase transition in response to pH, temperature and ionic strength [13]. The diameter of GNG particles was determined as 106±2.68 nm and approximately 15 gold particles were included in each PEGylated nanogel; these data were obtained using transmission electron microscopy (TEM) [12].…”

Section: Introductionmentioning

confidence: 99%

Radiosensitization of tumor cells through endoplasmic reticulum stress induced by PEGylated nanogel containing gold nanoparticles

et al. 2014

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High atomic number molecules, such as gold and platinum, are known to enhance the biological effect of X-irradiation. This study was aimed to determine the radiosensitizing potential of PEGylated nanogel containing gold nanoparticles (GNG) and the cellular mechanism involved. GNG pretreatment increased the levels of reproductive cell death and apoptosis induced by X-irradiation. GNG accumulated in cytoplasm and increased the expression of endoplasmic reticulum (ER) stress-related protein. GNG suppressed the repair capacity of DNA after X-irradiation by down-regulating DNA repair-related proteins. Our results suggest that GNG radiosensitized cells by enhancing apoptosis and impairing DNA repair capacity via ER stress induction.

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“…The details of the synthesis procedure are described elsewhere. [17][18][19][20][21][22] The number-averaged molecular weight, M n , and M n /M w of the acetal-PEG-VB were 7870 and 1.07, respectively, where M w is the weight-averaged molecular weight. The PEGylated nanogels consisted of a DEAMA core and a shell composed of acetal-PEG-VB.…”

Section: Materials and Methods Materialsmentioning

confidence: 99%

“…[17][18][19][20][21][22] These nanogel particles may be applicable not only for drug delivery systems but also for various therapeutics and pathog-nomony, such as small interfering RNA delivery, cancer photothermal therapy, magnetic resonance imaging and apoptosis probes, that are used to monitor responses to cancer therapy. For all of these applications, the poly[2-(N,N-diethylaminoethyl) methacrylate] gel core of the nanogels acts as a reservoir for anticancer drugs, small interfering RNAs, and metal nanoparticles through hydrophobic interactions, electrostatic interactions and coordination bonds with poly[2-(N,Ndiethylaminoethyl) methacrylate] segments.…”

Section: Introductionmentioning

confidence: 99%

“…In previous studies, pH-dependent changes in the hydrodynamic radius of nanogel particles were visualized with dynamic light scattering (DLS); [17][18][19][20][21][22] the size of nanogel particles increases under acidic conditions and decreases under alkaline conditions. Although DLS is widely used to characterize particle size and size distribution, estimates using DLS are often affected by many factors, including particle shape and surface structure, as discussed in Results and discussion.…”

Section: Introductionmentioning

confidence: 99%

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Dependence of the swelling behavior of a pH-responsive PEG-modified nanogel on the cross-link density

Tamura

Shinohara

Tamura

et al. 2011

Polym J

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We report pH-responsive structural changes in PEG-modified (PEGylated) nanogels, as determined by using small-angle X-ray scattering and dynamic light scattering. The size of the nanogels discontinuously increased at a lower pH than the pK a of the nanogels. This size increase was attributed to the swelling of the core part of the nanogel upon a change in pH. The swelling behavior was dependent on the cross-link density of the core. When the cross-link density was low, the core swelled greatly with preserving the polydispersity in size and maintained a constant shape; however, when the cross-link density was high, the core swelled minimally, and only the polydispersity increased. This difference in swelling behavior is discussed in terms of the inhomogeneous structural distribution of cross-links in the core.

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Synthesis, characterization, and biomedical applications of core–shell-type stimuli-responsive nanogels – Nanogel composed of poly[2-(N,N-diethylamino)ethyl methacrylate] core and PEG tethered chains

Cited by 60 publications

References 106 publications

Design and Preparation of a Nanoprobe for Imaging Inflammation Sites

Design and Preparation of a Nanoprobe for Imaging Inflammation Sites

Radiosensitization of tumor cells through endoplasmic reticulum stress induced by PEGylated nanogel containing gold nanoparticles

Dependence of the swelling behavior of a pH-responsive PEG-modified nanogel on the cross-link density

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