Molecular Brushes – Densely Grafted Copolymers

Sumerlin, Brent S.; Matyjaszewski, Krzysztof

doi:10.1002/9783527631421.ch26

Cited by 7 publications

(4 citation statements)

References 157 publications

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“…The comblike topology was obtained here by a graft-through method. 39 The statistical distribution of the two types of monomer units was ensured by the similar reactivity ratios of the selected methacrylate comonomers.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…The tolerance of the RAFT mechanism to various functional groups enabled the direct copolymerization of a PEG methacrylate macromonomer with either MAA or MAPA, following simple synthetic procedures in solution. The comblike topology was obtained here by a graft-through method . The statistical distribution of the two types of monomer units was ensured by the similar reactivity ratios of the selected methacrylate comonomers.…”

Section: Results and Discussionmentioning

confidence: 99%

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PEGylated Anionic Magnetofluorescent Nanoassemblies: Impact of Their Interface Structure on Magnetic Resonance Imaging Contrast and Cellular Uptake

Linot

Poly

Boucard

et al. 2017

ACS Appl. Mater. Interfaces

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Controlling the interactions of functional nanostructures with water and biological media represents high challenges in the field of bioimaging applications. Large contrast at low doses, high colloidal stability in physiological conditions, the absence of cell cytotoxicity, and efficient cell internalization represent strong additional needs. To achieve such requirements, we report on high-payload magnetofluorescent architectures made of a shell of superparamagnetic iron oxide nanoparticles tightly anchored around fluorescent organic nanoparticles. Their external coating is simply modulated using anionic polyelectrolytes in a final step to provide efficient magnetic resonance imaging (MRI) and fluorescence imaging of live cells. Various structures of PEGylated polyelectrolytes have been synthesized and investigated, differing from their iron oxide complexing units (carboxylic vs phosphonic acid), their structure (block- or comblike), their hydrophobicity, and their fabrication process [conventional or reversible addition-fragmentation chain transfer (RAFT)-controlled radical polymerization] while keeping the central magnetofluorescent platforms the same. Combined photophysical, magnetic, NMRD, and structural investigations proved the superiority of RAFT polymer coatings containing carboxylate units and a hydrophobic tail to impart the magnetic nanoassemblies (NAs) with enhanced-MRI negative contrast, characterized by a high r/r ratio and a transverse relaxation r equal to 21 and 125 s mmol L, respectively, at 60 MHz clinical frequency (∼1.5 T). Thanks to their dual modality, cell internalization of the NAs in mesothelioma cancer cells could be evidenced by both confocal fluorescence microscopy and magnetophoresis. A 72 h follow-up showed efficient uptake after 24 h with no notable cell mortality. These studies again pointed out the distinct behavior of RAFT polyelectrolyte-coated bimodal NAs that internalize at a slower rate with no adverse cytotoxicity. Extension to multicellular tumor cell spheroids that mimic solid tumors revealed the successful internalization of the NAs in the periphery cells, which provides efficient deep-imaging labels thanks to their induced T* contrast, large emission Stokes shift, and bright dotlike signal, popping out of the strong spheroid autofluorescence.

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Section: ■ Results and Discussionmentioning

confidence: 99%

Section: Results and Discussionmentioning

confidence: 99%

PEGylated Anionic Magnetofluorescent Nanoassemblies: Impact of Their Interface Structure on Magnetic Resonance Imaging Contrast and Cellular Uptake

Linot

Poly

Boucard

et al. 2017

ACS Appl. Mater. Interfaces

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“…Advances in synthetic polymer chemistry have enabled access to macromolecules with complex topologies, including, for example, macrocycles, bottlebrushes, stars, and dendronized, hyperbranched, figure 8 or theta-shaped chains. − The generation of cyclic topologies is of particular interest as their solution and bulk properties differ from those of linear polymers of similar molecular weights. − …”

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confidence: 99%

Ultra-High-Molecular-Weight Macrocyclic Bottlebrushes via Post-Polymerization Modification of a Cyclic Polymer

et al. 2020

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Polymer bottlebrushes are complex macromolecular nanostructures with polymeric side chains densely grafted to a polymer backbone. In this work, a synthetic strategy for the synthesis of cyclic bottlebrush polymers was exhibited by combining ring-expansion polymerization (REP) and atom transfer radical polymerization (ATRP) by a grafting-from approach. A variety of ultra-high-molecular-weight (on the order of MDa) macrocyclic bottlebrushes were generated by employing this method. Direct visualization of the macrocyclic bottlebrushes was achieved by atomic force microscopy. Furthermore, a linear bottlebrush polymer was synthesized independently by a similar synthetic route to investigate topological differences between cyclic and linear architectures.

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“…Surface-induced polymerization reactions (grafting-from-methods) − often constitute an important and fruitful combination of controlled polymerization methods with surface and interface functionalization. , Thus, a large variety of polymerization reactions from surfaces have been described generating polymer brushes in variable density, taking advantage of the use of controlled radical polymerization (such as ATRP, ,,− NMP, , RAFT), living anionic or living cationic polymerization . Planar surfaces (such as Au−, SiO 2 ), or curved surfaces (i.e.…”

Section: Introductionmentioning

confidence: 99%

Grafting Polyisobutylene from Nanoparticle Surfaces: Concentration and Surface Effects on Livingness

Binder

Zirbs

Machl³

et al. 2009

Macromolecules

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We report on the grafting-from living cationic polymerization of isobutylene from SiO 2nanoparticles surfaces. After modification of the NP-surfaces (SiO 2 ; 6 nm) initiators (I) for the cationic polymerization of isobutylene (IB) were grafted onto the NP surface in variable densities (0.1-0.85 molecules initiator/nm 2 ). With densely packed initiators (0.85 molecules initiator/nm 2 ) PIB-brushes with controlled molecular weights (5000-50 000 g mol -1 ) could be obtained. Various concentration-ranges of initiatormoieties in solution as well as isobutylene were studied, revealing a controlled polymerization process only in the range between [I] = 0.4-30 mM and [IB] = ∼0.04-3.3 M without the use of sacrificial soluble initiating systems, thus enabling a high-volume density polymerization of grafted nanoparticles without homopolymer formation. At high grafting densities (0.6-0.8 initiator molecules/nm 2 ), the polymerization proceeded with three different rate-constants, with a slower polymerization at the beginning and increasing rates of polymerization after ∼300 and 600 s, respectively. With reduced initiators densities (below 0.4 molecules initiator/nm 2 ) loss of control over the polymerization process and a significant change of the polymerization kinetics was observed.

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Molecular Brushes – Densely Grafted Copolymers

Cited by 7 publications

References 157 publications

PEGylated Anionic Magnetofluorescent Nanoassemblies: Impact of Their Interface Structure on Magnetic Resonance Imaging Contrast and Cellular Uptake

PEGylated Anionic Magnetofluorescent Nanoassemblies: Impact of Their Interface Structure on Magnetic Resonance Imaging Contrast and Cellular Uptake

Ultra-High-Molecular-Weight Macrocyclic Bottlebrushes via Post-Polymerization Modification of a Cyclic Polymer

Grafting Polyisobutylene from Nanoparticle Surfaces: Concentration and Surface Effects on Livingness

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