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Ulker D, Neal TJ, Crawford A, Armes SP. Thermoresponsive Poly( N, N'-dimethylacrylamide)-Based Diblock Copolymer Worm Gels via RAFT Solution Polymerization: Synthesis, Characterization, and Cell Biology Applications. Biomacromolecules 2023; 24:4285-4302. [PMID: 37616242 PMCID: PMC10498450 DOI: 10.1021/acs.biomac.3c00635] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Revised: 08/09/2023] [Indexed: 08/26/2023]
Abstract
RAFT solution polymerization is used to polymerize 2-hydroxypropyl methacrylate (HPMA). The resulting PHPMA precursor is then chain-extended using N,N'-dimethylacrylamide (DMAC) to produce a series of thermoresponsive PHPMA-PDMAC diblock copolymers. Such amphiphilic copolymers can be directly dispersed in ice-cold water and self-assembled at 20 °C to form spheres, worms, or vesicles depending on their copolymer composition. Construction of a pseudo-phase diagram is required to identify the pure worm phase, which corresponds to a rather narrow range of PDMAC DPs. Such worms form soft, free-standing gels in aqueous solution at around ambient temperature. Rheology studies confirm the thermoresponsive nature of such worms, which undergo a reversible worm-to-sphere on cooling below ambient temperature. This morphological transition leads to in situ degelation, and variable temperature 1H NMR studies indicate a higher degree of (partial) hydration for the weakly hydrophobic PHPMA chains at lower temperatures. The trithiocarbonate end-group located at the end of each PDMAC chain can be removed by treatment with excess hydrazine. The resulting terminal secondary thiol group can form disulfide bonds via coupling, which produces PHPMA-PDMAC-PHPMA triblock copolymer chains. Alternatively, this reactive thiol group can be used for conjugation reactions. A PHPMA141-PDMAC36 worm gel was used to store human mesenchymal stem cells (MSCs) for up to three weeks at 37 °C. MSCs retrieved from this gel subsequently underwent proliferation and maintained their ability to differentiate into osteoblastic cells.
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Affiliation(s)
- Damla Ulker
- Dainton
Building, Department of Chemistry, University
of Sheffield, Brook Hill, Sheffield, South
Yorkshire S3 7HF, UK
- Faculty
of Pharmacy, Department of Pharmaceutical Basic Sciences, Near East University, Nicosia, Northern Cyprus TR-99138, Turkey
| | - Thomas J. Neal
- Dainton
Building, Department of Chemistry, University
of Sheffield, Brook Hill, Sheffield, South
Yorkshire S3 7HF, UK
| | - Aileen Crawford
- School
of Clinical Dentistry, University of Sheffield, Claremont Crescent, Sheffield, South Yorkshire S10 2TA, UK
| | - Steven P. Armes
- Dainton
Building, Department of Chemistry, University
of Sheffield, Brook Hill, Sheffield, South
Yorkshire S3 7HF, UK
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György C, Verity C, Neal TJ, Rymaruk MJ, Cornel EJ, Smith T, Growney DJ, Armes SP. RAFT Dispersion Polymerization of Methyl Methacrylate in Mineral Oil: High Glass Transition Temperature of the Core-Forming Block Constrains the Evolution of Copolymer Morphology. Macromolecules 2021. [DOI: 10.1021/acs.macromol.1c01528] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Affiliation(s)
- Csilla György
- Dainton Building, Department of Chemistry, University of Sheffield, Brook Hill, Sheffield, South Yorkshire S3 7HF, U.K
| | - Chloe Verity
- Dainton Building, Department of Chemistry, University of Sheffield, Brook Hill, Sheffield, South Yorkshire S3 7HF, U.K
| | - Thomas J. Neal
- Dainton Building, Department of Chemistry, University of Sheffield, Brook Hill, Sheffield, South Yorkshire S3 7HF, U.K
| | - Matthew J. Rymaruk
- Dainton Building, Department of Chemistry, University of Sheffield, Brook Hill, Sheffield, South Yorkshire S3 7HF, U.K
| | - Erik J. Cornel
- Dainton Building, Department of Chemistry, University of Sheffield, Brook Hill, Sheffield, South Yorkshire S3 7HF, U.K
| | - Timothy Smith
- Lubrizol Ltd., Nether Lane, Hazelwood, Derbyshire DE56 4AN, U.K
| | | | - Steven P. Armes
- Dainton Building, Department of Chemistry, University of Sheffield, Brook Hill, Sheffield, South Yorkshire S3 7HF, U.K
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3
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György C, Derry MJ, Cornel EJ, Armes SP. Synthesis of Highly Transparent Diblock Copolymer Vesicles via RAFT Dispersion Polymerization of 2,2,2-Trifluoroethyl Methacrylate in n-Alkanes. Macromolecules 2021; 54:1159-1169. [PMID: 33583957 PMCID: PMC7879428 DOI: 10.1021/acs.macromol.0c02646] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Revised: 01/06/2021] [Indexed: 01/28/2023]
Abstract
RAFT dispersion polymerization of 2,2,2-trifluoroethyl methacrylate (TFEMA) is performed in n-dodecane at 90 °C using a relatively short poly(stearyl methacrylate) (PSMA) precursor and 2-cyano-2-propyl dithiobenzoate (CPDB). The growing insoluble poly(2,2,2-trifluoroethyl methacrylate) (PTFEMA) block results in the formation of PSMA-PTFEMA diblock copolymer nano-objects via polymerization-induced self-assembly (PISA). GPC analysis indicated narrow molecular weight distributions (M w/M n ≤ 1.34) for all copolymers, with 19F NMR studies indicating high TFEMA conversions (≥95%) for all syntheses. A pseudo-phase diagram was constructed to enable reproducible targeting of pure spheres, worms, or vesicles by varying the target degree of polymerization of the PTFEMA block at 15-25% w/w solids. Nano-objects were characterized using dynamic light scattering, transmission electron microscopy, and small-angle X-ray scattering. Importantly, the near-identical refractive indices for PTFEMA (1.418) and n-dodecane (1.421) enable the first example of highly transparent vesicles to be prepared. The turbidity of such dispersions was examined between 20 and 90 °C. The highest transmittance (97% at 600 nm) was observed for PSMA9-PTFEMA294 vesicles (237 ± 24 nm diameter; prepared at 25% w/w solids) in n-dodecane at 20 °C. Interestingly, targeting the same diblock composition in n-hexadecane produced a vesicle dispersion with minimal turbidity at a synthesis temperature of 90 °C. This solvent enabled in situ visible absorption spectra to be recorded during the synthesis of PSMA16-PTFEMA86 spheres at 15% w/w solids, which allowed the relatively weak n→π* band at 515 nm assigned to the dithiobenzoate chain-ends to be monitored. Unfortunately, the premature loss of this RAFT chain-end occurred during the RAFT dispersion polymerization of TFEMA at 90 °C, so meaningful kinetic data could not be obtained. Furthermore, the dithiobenzoate chain-ends exhibited a λmax shift of 8 nm relative to that of the dithiobenzoate-capped PSMA9 precursor. This solvatochromatic effect suggests that the problem of thermally labile dithiobenzoate chain-ends cannot be addressed by performing the TFEMA polymerization at lower temperatures.
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Affiliation(s)
- Csilla György
- Dainton Building, Department
of Chemistry, The University of Sheffield, Brook Hill, Sheffield, South Yorkshire S3 7HF, U.K.
| | | | | | - Steven P. Armes
- Dainton Building, Department
of Chemistry, The University of Sheffield, Brook Hill, Sheffield, South Yorkshire S3 7HF, U.K.
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Guerre M, Lopez G, Améduri B, Semsarilar M, Ladmiral V. Solution self-assembly of fluorinated polymers, an overview. Polym Chem 2021. [DOI: 10.1039/d1py00221j] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The incorporation of fluorinated moieties into a polymer can confer unique properties and often lead in solution to original morphologies endowed with rare properties.
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Affiliation(s)
- Marc Guerre
- Laboratoire des IMRCP
- Université de Toulouse
- CNRS UMR 5623
- Université Paul Sabatier
- 31062 Toulouse Cedex 9
| | - Gérald Lopez
- ICGM
- Univ Montpellier-CNRS-ENSCM
- Montpellier
- France
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Parker B, Derry MJ, Ning Y, Armes SP. Exploring the Upper Size Limit for Sterically Stabilized Diblock Copolymer Nanoparticles Prepared by Polymerization-Induced Self-Assembly in Non-Polar Media. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:3730-3736. [PMID: 32216260 PMCID: PMC7161081 DOI: 10.1021/acs.langmuir.0c00211] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Revised: 03/26/2020] [Indexed: 06/10/2023]
Abstract
Reversible addition-fragmentation chain transfer (RAFT) dispersion polymerization of benzyl methacrylate is used to prepare a series of well-defined poly(stearyl methacrylate)-poly(benzyl methacrylate) (PSMA-PBzMA) diblock copolymer nanoparticles in mineral oil at 90 °C. A relatively long PSMA54 precursor acts as a steric stabilizer block and also ensures that only kinetically trapped spheres are obtained, regardless of the target degree of polymerization (DP) for the core-forming PBzMA block. This polymerization-induced self-assembly (PISA) formulation provides good control over the particle size distribution over a wide size range (24-459 nm diameter). 1H NMR spectroscopy studies confirm that high monomer conversions (≥96%) are obtained for all PISA syntheses while transmission electron microscopy and dynamic light scattering analyses show well-defined spheres with a power-law relationship between the target PBzMA DP and the mean particle diameter. Gel permeation chromatography studies indicate a gradual loss of control over the molecular weight distribution as higher DPs are targeted, but well-defined morphologies and narrow particle size distributions can be obtained for PBzMA DPs up to 3500, which corresponds to an upper particle size limit of 459 nm. Thus, these are among the largest well-defined spheres with reasonably narrow size distributions (standard deviation ≤20%) produced by any PISA formulation. Such large spheres serve as model sterically stabilized particles for analytical centrifugation studies.
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Affiliation(s)
- Bryony
R. Parker
- Dainton Building, Department
of Chemistry, University of Sheffield, Brook
Hill, Sheffield, South Yorkshire S3 7HF, United Kingdom
| | | | - Yin Ning
- Dainton Building, Department
of Chemistry, University of Sheffield, Brook
Hill, Sheffield, South Yorkshire S3 7HF, United Kingdom
| | - Steven P. Armes
- Dainton Building, Department
of Chemistry, University of Sheffield, Brook
Hill, Sheffield, South Yorkshire S3 7HF, United Kingdom
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Smith GN, Canning SL, Derry MJ, Mykhaylyk OO, Norman SE, Armes SP. Influence of an ionic comonomer on polymerization-induced self-assembly of diblock copolymers in non-polar media. Polym Chem 2020. [DOI: 10.1039/d0py00101e] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Incorporating an appropriate ionic comonomer into a polymerization-induced self-assembly (PISA) formulation can provide convenient access to block copolymer worms and vesicles in non-polar media, in addition to spheres.
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Affiliation(s)
- Gregory N. Smith
- Department of Chemistry
- University of Sheffield
- UK
- Niels Bohr Institute
- University of Copenhagen
| | | | | | | | - Sarah E. Norman
- School of Chemistry and Chemical Engineering
- The QUILL Centre
- Queen's University Belfast
- Belfast BT9 5AG
- UK
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