Synthesis and Characterization of pH-Responsive Copolymer Microgels with Tunable Volume Phase Transition Temperatures

Debord, Justin; Lyon, L. Andrew

doi:10.1021/la0342924

Cited by 202 publications

(168 citation statements)

References 21 publications

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“…We and others have copolymerized ionic monomers with pNIPAm to create pH-responsive microgels. [22,29,[101][102][103][104][105] We have also copolymerized a hydrophobic comonomer N-tert-butylacrylamide (TBA, H 2 C=CHCONHC(CH 3 ) 3 ) to give pH and temperature responsive microgels; these particles exhibit phase transitions at lower temperatures owing to the increase in hydrophobicity of the gel while retaining a pH-tunable VPTT. [105] Similarly, other functionalities can also be copolymerized into these particles by this method.…”

Section: Emulsion and Precipitation Polymerizationmentioning

confidence: 99%

Soft Nanotechnology with Soft Nanoparticles

2005

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The last decade of research in the physical sciences has seen a dramatic increase in the study of nanoscale materials. Today, "nanoscience" has emerged as a multidisciplinary effort, wherein obtaining a fundamental understanding of the optical, electrical, magnetic, and mechanical properties of nanostructures promises to deliver the next generation of functional materials for a wide range of applications. While this range of efforts is extremely broad, much of the work has focused on "hard" materials, such as Buckyballs, carbon nanotubes, metals, semiconductors, and organic or inorganic dielectrics. Meanwhile, the soft materials of current interest typically include conducting or emissive polymers for "plastic electronics" applications. Despite the continued interest in these established areas of nanoscience, new classes of soft nanomaterials are being developed from more traditional polymeric constructs. Specifically, nanostructured hydrogels are emerging as a promising group of materials for multiple biotechnology applications as the need for advanced materials in the post-genomic era grows. This review will present some of the recent advances in the marriage between water-swellable networks and nanoscience.

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Section: Emulsion and Precipitation Polymerizationmentioning

confidence: 99%

Soft Nanotechnology with Soft Nanoparticles

2005

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“…As an example, temperature-and pH-sensitive microgels were obtained by copolymerization of NIPAAm with e.g. acrylic acid 52 or aminoethyl methacrylate hydrochloride. 53 In addition, precipitation polymerization of functional monomers in the presence of preformed seed particles was demonstrated to yield such complex structures as e.g.…”

Section: Microgels By Dispersion/precipitation Polymerizationmentioning

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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“…Recent studies led to the synthesis of nano-or micro-sized PNIPAm beads by sedimentation polymerization [2], free-radical precipitation polymerization [3], or microemulsion polymerization [4; 5]. However, most procedures made use of surfactants and elevated reaction temperatures, both factors affecting the stability of peptides and proteins.…”

Section: Introductionmentioning

confidence: 99%

Poly(N-isopropylacrylamide) gel beads prepared by waterin- oil suspension polymerization for the adsorption of fluorescently tagged hepcidin

2009

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Poly(N-isopropylacrylamide) (PNIPAm) gel beads were prepared by water in oil (w/o) suspension polymerization using aqueous acetonitrile to dissolve the monomer phase, toluene or cyclohexane as the continuous phase and ethyl cellulose (EC) as the stabilizer. The beads were analyzed by FT-IR and their morphology was investigated by optical and electron microscopy. The advantages of this novel synthetic method for PNIPAm preparation include efficient polymerization and mild experimental conditions, as well as the formation of spherical and relatively uniformly sized particles. The microgels were then evaluated for their efficiency to absorb fluorescently labelled hepcidin. The beads were found to rapidly capture the target peptide from neutral aqueous solutions. Notably, bovine serum albumin (BSA) did not bind to the polymer beads at the cross-linking ratio used; therefore, size-exclusion properties may be controlled by finely tuning monomer to cross-linker ratio and/or monomer concentration during polymer design. The route could potentially be useful for diagnostic, drug delivery or peptide immobilization, as well as for the molecular imprinting of peptides and proteins.

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Synthesis and Characterization of pH-Responsive Copolymer Microgels with Tunable Volume Phase Transition Temperatures

Cited by 202 publications

References 21 publications

Soft Nanotechnology with Soft Nanoparticles

Soft Nanotechnology with Soft Nanoparticles

Light-Sensitive Polymeric Nanoparticles Based on Photo-Cleavable Chromophores

Poly(N-isopropylacrylamide) gel beads prepared by waterin- oil suspension polymerization for the adsorption of fluorescently tagged hepcidin

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