Monodisperse Thermoresponsive Microgels with Tunable Volume‐Phase Transition Kinetics

Chu, Liang‐Yin; Kim, Jinwoong; Shah, Rhutesh K.; Weitz, David A.

doi:10.1002/adfm.200700379

Cited by 152 publications

(145 citation statements)

References 44 publications

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“…Despite that, the formation method of microgels using micro-fluidics gives rise to well defined spherical particles in the size range of several micrometers. 80 …”

Section: Microgel Synthesis In Other Compartmentsmentioning

confidence: 99%

Light-Sensitive Polymeric Nanoparticles Based on Photo-Cleavable Chromophores

Klinger

2013

Springer Theses

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This thesis focuses on the design, synthesis and characterization of novel photo-sensitive microgels and nanoparticles as potential materials for the loading and light-triggered release/accessibility of functional compounds. In order to realize this concept, different approaches to irradiation-dependent response mechanisms have been investigated.Novel light-cleavable divinyl functionalized monomeric crosslinkers based on o-nitrobenzyl derivatives were synthesized and used for the preparation of either PMMA or hydroxyl functionalized PHEMA microgels swellable and degradable in organic solvents. By the introduction of anionic MAA moieties into the PHEMA microgels, this concept was successfully transferred to double stimuli-responsive p(HEMA-co-MAA) hydrogel nanoparticles exhibiting a pH-dependent swelling and light-induced degradation behavior in aqueous media. This sensitivity to two orthogonal triggers is proposed to combine a pHinduced post-formation loading mechanism with a pH-and light-triggered release. In addition, a new class of enzyme-and light-sensitive PAAm microgels based on (meth-)acrylate functionalized dextrans as photo-and enzymatically degradable macromolecular crosslinkers was developed by introducing a photo-labile linker between the enzymatically degradable dextran chain and the polymerizable vinyl moieties. Here, the water solubility of the crosslinkers is assumed to enable an in situ loading approach of hydrophilic compounds.A different approach to the loading of microgels is based on photo-labile covalent microgel-drug conjugates. The first step to the realization of this concept was achieved by the development of a novel functional monomer consisting of a doxorubicin molecule covalently attached to a radically polymerizable methacrylate group via a photo-cleavable linker.Moreover, in order to enable the release of hydrophobic substances in aqueous media, hydrophobic nanoparticles consisting of a photo-resist polymer were designed to be degradable upon irradiation in water. Light-triggered conversion of the initial hydrophobic polymer into hydrophilic PMAA induced in situ particle dissolution and release of nile red.Since the introduction of a stimuli-responsive shell around a microgel is assumed to prevent leakage of embedded compounds, studies on non-stimuli-responsive shell formation around preformed microgel seed particles and the formation of microgel cores in polymeric shells were conducted to investigate potential synthetic pathways to this approach.In a last attempt, the surface of PHEMA and p(HEMA-co-MAA) microgels was functionalized with cinnamoyl groups in order to trigger the (reversible) particles interaction with each other by light-induced [2+2] cycloaddition reactions.

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“…Despite that, the formation method of microgels using micro-fluidics gives rise to well defined spherical particles in the size range of several micrometers. 80 …”

Section: Microgel Synthesis In Other Compartmentsmentioning

confidence: 99%

Light-Sensitive Polymeric Nanoparticles Based on Photo-Cleavable Chromophores

Klinger

2013

Springer Theses

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“…They are widely used in various applications such as hygienic, foods, cosmetics, and agriculture 1 . This accounts for increase in the worldwide production of superabsorbent polymers (SAPs) from 6000 tons in 1983 to 450000 tons in 1996 [2][3][4] . Nowadays, the worldwide production of SAPs is more than one million tons in year.…”

Section: Introductionmentioning

confidence: 99%

“…Nowadays, the worldwide production of SAPs is more than one million tons in year. Hence, synthesis and characterization of superabsorbent hydrogels is the main goal of the several research groups in the world [3][4][5][6][7] .…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Investigation of a Novel pH- and Salt-Responsive Superabsorbent Hydrogel Based on Pectin

Sadeghi¹,

Mohammadinasab²,

Shafiei³

2012

Orientjchem.

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In the present paper, attention is paid to synthesis and investigates swelling behavior of a superabsorbent hydrogel based on Pectin (Pec) and polyacrylic acid (PAcA). acrylic acid (AcA) was graft copolymerized onto Pectin backbones by a free radical polymerization technique using ammonium persulfate (APS) as initiator and methylene bisacrylamide (MBA) as a crosslinker. A proposed mechanism for hydrogel formation was suggested and the structure of the product was established using FTIR and SEM spectroscopies. Under the optimized conditions concluded, maximum capacity of swelling in distilled water was found to be 348 g/g. Absorbency of the synthesized hydrogels was also measured in NaCl and CaCl 2 salt solutions. Results indicated that the swelling ratios in compare to water decreased with an increase in the ionic strength of solution. In addition, swelling capacity was conducted in solutions with pH ranged from 1 to 13. The H-Pecpoly(sodium acrylate) hydrogel exhibited a pH-responsiveness character so that a swellingdeswelling pulsatile behavior was recorded at pHs 3 and 9.

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“…They are widely used as templates for the synthesis of multicompartment microspheres [1][2][3][4][5] and core-shell microcapsules, 6-10 as microreactors for chemical reactions, 11 and as encapsulants for actives such as drugs [12][13][14][15][16] and nutrients. [17][18][19] Multiple emulsions containing droplets with different contents in the same internal level are important for co-encapsulating incompatible actives or chemicals for synergistic delivery or for biochemical or chemical reactions, and for fabricating hierarchical multicompartment materials.…”

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confidence: 99%