1
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Du R, Fielding LA. Preparation of polymer nanoparticle-based complex coacervate hydrogels using polymerisation-induced self-assembly derived nanogels. SOFT MATTER 2023; 19:2074-2081. [PMID: 36857682 DOI: 10.1039/d2sm01534j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
This paper reports a generic method to prepare polymer nanoparticle-based complex coacervate (PNCC) hydrogels by employing rationally designed nanogels synthesised by reversible addition-fragmentation chain-transfer (RAFT)-mediated polymerisation-induced self-assembly (PISA). Specifically, a poly(potassium 3-sulfopropyl methacrylate) (PKSPMA) macromolecular chain-transfer agent (macro-CTA) was synthesised via RAFT solution polymerisation followed by chain-extension with a statistical copolymer of benzyl methacrylate (BzMA) and methacrylic acid (MAA) at pH 2. Thus, pH-responsive nanoparticles (NPs) comprising a hydrophobic polyacid core-forming block and a sulfonate-functional stabiliser block were formed. With the introduction of methacrylic acid into the core of the NPs, they become swollen with increasing pH, as judged by dynamic light scattering (DLS), indicating nanogel-type behaviour. PNCC hydrogels were prepared by simply mixing the PISA-derived nanogels and cationic branched polyethyleneimine (bPEI) at 20% w/w. In the absence of MAA in the core of the NPs, gel formation was not observed. The mass ratio between the nanogels and bPEI affected resulting hydrogel strength and a mixture of bPEI and PKSPMA68-P(BzMA0.6-stat-MAA0.4)300 NPs with a mass ratio of 0.14 at pH ∼7 resulted in a hydrogel with a storage modulus of approximately 2000 Pa, as determined by oscillatory rheology. This PNCC hydrogel was shear-thinning and injectable, with recovery of gel strength occurring rapidly after the removal of shear.
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Affiliation(s)
- Ruiling Du
- Department of Materials, School of Natural Sciences, University of Manchester, Oxford Road, Manchester, M13 9PL, UK.
- Henry Royce Institute, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK
| | - Lee A Fielding
- Department of Materials, School of Natural Sciences, University of Manchester, Oxford Road, Manchester, M13 9PL, UK.
- Henry Royce Institute, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK
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2
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Nguyen NT, Jennings J, Milani AH, Martino CDS, Nguyen LTB, Wu S, Mokhtar MZ, Saunders JM, Gautrot JE, Armes SP, Saunders BR. Highly Stretchable Conductive Covalent Coacervate Gels for Electronic Skin. Biomacromolecules 2022; 23:1423-1432. [PMID: 35188757 PMCID: PMC9098112 DOI: 10.1021/acs.biomac.1c01660] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 02/08/2022] [Indexed: 01/29/2023]
Abstract
Highly stretchable electrically conductive hydrogels have been extensively researched in recent years, especially for applications in strain and pressure sensing, electronic skin, and implantable bioelectronic devices. Herein, we present a new cross-linked complex coacervate approach to prepare conductive hydrogels that are both highly stretchable and compressive. The gels involve a complex coacervate between carboxylated nanogels and branched poly(ethylene imine), whereby the latter is covalently cross-linked by poly(ethylene glycol) diglycidyl ether (PEGDGE). Inclusion of graphene nanoplatelets (Gnp) provides electrical conductivity as well as tensile and compressive strain-sensing capability to the hydrogels. We demonstrate that judicious selection of the molecular weight of the PEGDGE cross-linker enables the mechanical properties of these hydrogels to be tuned. Indeed, the gels prepared with a PEGDGE molecular weight of 6000 g/mol defy the general rule that toughness decreases as strength increases. The conductive hydrogels achieve a compressive strength of 25 MPa and a stretchability of up to 1500%. These new gels are both adhesive and conformal. They provide a self-healable electronic circuit, respond rapidly to human motion, and can act as strain-dependent sensors while exhibiting low cytotoxicity. Our new approach to conductive gel preparation is efficient, involves only preformed components, and is scalable.
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Affiliation(s)
- Nam T. Nguyen
- Department
of Materials, University of Manchester, MSS Tower, Manchester M13 9PL, U.K.
| | - James Jennings
- Department
of Chemistry, University of Sheffield, Sheffield S3 7HF, U.K.
| | - Amir H. Milani
- Department
of Materials, University of Manchester, MSS Tower, Manchester M13 9PL, U.K.
| | - Chiara D. S. Martino
- School
of Engineering and Materials Science, Queen
Mary University of London, London E1 4NS, U.K.
| | - Linh T. B. Nguyen
- Eastman
Dental Institute, University College London, London WC1X 8LD, U.K.
| | - Shanglin Wu
- Department
of Materials, University of Manchester, MSS Tower, Manchester M13 9PL, U.K.
| | - Muhamad Z. Mokhtar
- Department
of Materials, University of Manchester, MSS Tower, Manchester M13 9PL, U.K.
| | - Jennifer M. Saunders
- Department
of Materials, University of Manchester, MSS Tower, Manchester M13 9PL, U.K.
| | - Julien E. Gautrot
- School
of Engineering and Materials Science, Queen
Mary University of London, London E1 4NS, U.K.
| | - Steven P. Armes
- Department
of Chemistry, University of Sheffield, Sheffield S3 7HF, U.K.
| | - Brian R. Saunders
- Department
of Materials, University of Manchester, MSS Tower, Manchester M13 9PL, U.K.
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3
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Singh VK, Kumar K, Singh N, Tiwari R, Krishnamoorthi S. Swift catalytic reduction of hazardous pollutants by new generation microgels. SOFT MATTER 2022; 18:535-544. [PMID: 34919101 DOI: 10.1039/d1sm01559a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
In this manuscript, we report for the first time a new generation microgel synthesis without using any divinyl functionalized cross-linker. A new generation less crosslinked microgel structure has been achieved by optimizing the amount of N-hydroxy methyl acrylamide (NHMA) and using a fixed amount of styrene (St), acrylic acid (AA) and N-vinyl pyrrolidone (NVP) via a free radical emulsion solution polymerization technique. Poly(NHMA) works as a hydrophilic as well as a crosslinking agent. Furthermore, microgels have been upgraded into a composite by incorporation of Ag nanoparticles for catalytic reduction applications. Microgels and their composites have been characterized by EDAX, FT-IR, particle size analyzer, SEM, TEM, TGA, UV-vis spectroscopy and XRD. Methylene blue (MB) dye and p-nitrophenol (PNP) were chosen as model hazardous pollutants for catalytic reduction applications. Microgels efficiently adsorb both pollutants over the surface and microgel_Ag composites dramatically reduced both pollutants in the non-toxic form at room temperature by using smaller doses of NaBH4.
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Affiliation(s)
- Vinai Kumar Singh
- Department of Chemistry & Environmental Science, Madan Mohan Malaviya University of Technology, Gorakhpur 273010, UP, India.
| | - Krishna Kumar
- Department of Chemistry & Environmental Science, Madan Mohan Malaviya University of Technology, Gorakhpur 273010, UP, India.
| | - Nishant Singh
- University Department of Chemistry, Faculty of Science, Tilka Manjhi Bhagalpur University, Bhagalpur 812007, Bihar, India
| | - Rudramani Tiwari
- Department of Chemistry, Institute of Science, Banaras Hindu University, Varanasi 221005, UP, India
| | - S Krishnamoorthi
- Department of Chemistry, Institute of Science, Banaras Hindu University, Varanasi 221005, UP, India
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4
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Rodin M, Li J, Kuckling D. Dually cross-linked single networks: structures and applications. Chem Soc Rev 2021; 50:8147-8177. [PMID: 34059857 DOI: 10.1039/d0cs01585g] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Cross-linked polymers have attracted an immense attention over the years, however, there are many flaws of these systems, e.g. softness and brittleness; such materials possess non-adjustable properties and cannot recover from damage and thus are limited in their practical applications. Supramolecular chemistry offers a variety of dynamic interactions that when integrated into polymeric gels endow the systems with reversibility and responsiveness to external stimuli. A combination of different cross-links in a single gel could be the key to tackle these drawbacks, since covalent or chemical cross-linking serve to maintain the permanent shape of the material and to improve overall mechanical performance, whereas non-covalent cross-links impart dynamicity, reversibility, stimuli-responsiveness and often toughness to the material. In the present review we sought to give a comprehensive overview of the progress in design strategies of different types of dually cross-linked single gels made by researchers over the past decade as well as the successful implementations of these advances in many demanding fields where versatile multifunctional materials are required, such as tissue engineering, drug delivery, self-healing and adhesive systems, sensors as well as shape memory materials and actuators.
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Affiliation(s)
- Maksim Rodin
- Department of Chemistry, Paderborn University, Warburger Str. 100, 33098 Paderborn, Germany.
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5
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Bell D, Ludwanowski S, Lüken A, Sarikaya B, Walther A, Wessling M. Hydrogel membranes made from crosslinked microgel multilayers with tunable density. J Memb Sci 2021. [DOI: 10.1016/j.memsci.2020.118912] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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6
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Shanks HR, Wu S, Nguyen NT, Lu D, Saunders BR. Including fluorescent nanoparticle probes within injectable gels for remote strain measurements and discrimination between compression and tension. SOFT MATTER 2021; 17:1048-1055. [PMID: 33289763 DOI: 10.1039/d0sm01635g] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The ability to remotely and non-invasively monitor and measure the strain within injectable gels used to augment soft tissue is highly desirable. Such information could enable real-time monitoring of gel performance and bespoke gel design. We report progress towards this goal using two fluorescent particle probe systems included within two different injectable gels. The two injectable gels have been previously studied in the contexts of intervertebral disc repair and stretchable gels for cartilage repair. The two fluorophore particle probes are blue or near-infrared (NIR) emitting and are present at very low concentrations. The normalised photoluminescence (PL) intensity from the blue emitting probe is shown to equal the compressive deformation ratio of the gels. Furthermore, the normalised ratio of the PL intensities for the blue and NIR probes varies linearly with deformation ratio over a wide range (from 0.2 to 3.0) with a seamless transition from compression to tension. Hence, PL can discriminate between compression and tension. The new approach established here should apply to other gels and enable remote detection of whether a gel is being compressed or stretched as well as the extent. This study may provide an important step towards remotely and minimally invasively measuring the strain experienced by load-supporting gels in vivo.
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Affiliation(s)
- Hannah R Shanks
- School of Materials, University of Manchester, MSS Tower, Manchester, M13 9PL, UK.
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7
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Lu D, Zhu M, Jin J, Saunders BR. Triply-responsive OEG-based microgels and hydrogels: regulation of swelling ratio, volume phase transition temperatures and mechanical properties. Polym Chem 2021. [DOI: 10.1039/d1py00695a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Facile methods to coordinate swelling ratio, volume-phase transition temperatures and mechanical properties for pH-, thermal-, and cationic-responsive microgels and hydrogels.
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Affiliation(s)
- Dongdong Lu
- Department of Materials
- University of Manchester
- Manchester
- UK
| | - Mingning Zhu
- Department of Materials
- University of Manchester
- Manchester
- UK
| | - Jing Jin
- Department of Materials
- University of Manchester
- Manchester
- UK
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8
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Zhu M, Lu D, Lian Q, Wu S, Wang W, Lyon LA, Wang W, Bártolo P, Dickinson M, Saunders BR. Highly swelling pH-responsive microgels for dual mode near infra-red fluorescence reporting and imaging. NANOSCALE ADVANCES 2020; 2:4261-4271. [PMID: 36132786 PMCID: PMC9419105 DOI: 10.1039/d0na00581a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2020] [Accepted: 08/12/2020] [Indexed: 05/08/2023]
Abstract
Near infra-red (NIR) fluorescence is a desirable property for probe particles because such deeply penetrating light enables remote reporting of the local environment in complex surroundings and imaging. Here, two NIR non-radiative energy transfer (NRET) fluorophores (Cy5 and Cy5.5) are coupled to preformed pH-responsive poly(ethylacrylate-methacrylic acid-divinylbenzene) microgel particles (PEA-MAA-5/5.5 MGs) to obtain new NIR fluorescent probes that are cytocompatible and swell strongly. NIR ratiometric photoluminescence (PL) intensity analysis enables reporting of pH-triggered PEA-MAA-5/5.5 MG particle swelling ratios over a very wide range (from 1-90). The dispersions have greatly improved colloidal stability compared to a reference temperature-responsive NIR MG based on poly(N-isopropylacrylamide) (PNP-5/5.5). We also show that the wavelength of maximum PL intensity (λ max) is a second PL parameter that enables remote reporting of swelling for both PEA-MAA-5/5.5 and PNP-5/5.5 MGs. After internalization the PEA-MAA-5/5.5 MGs are successfully imaged in stem cells using NIR light. They are also imaged after subcutaneous injection into model tissue using NIR light. The new NIR PEA-MAA-5/5.5 MGs have excellent potential for reporting their swelling states (and any changes) within physiological settings as well as very high ionic strength environments (e.g., waste water).
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Affiliation(s)
- Mingning Zhu
- Department of Materials, University of Manchester, MSS Tower Manchester M13 9PL UK
| | - Dongdong Lu
- Department of Materials, University of Manchester, MSS Tower Manchester M13 9PL UK
| | - Qing Lian
- Department of Materials, University of Manchester, MSS Tower Manchester M13 9PL UK
| | - Shanglin Wu
- Department of Materials, University of Manchester, MSS Tower Manchester M13 9PL UK
| | - Wenkai Wang
- Department of Materials, University of Manchester, MSS Tower Manchester M13 9PL UK
| | - L Andrew Lyon
- Schmid College of Science and Technology, Chapman University Orange CA 92866 USA
- Fowler School of Engineering, Chapman University Orange CA 92866 USA
| | - Weiguang Wang
- Department of Mechanical, Aerospace and Civil Engineering, School of Engineering, Faculty of Science and Engineering, University of Manchester Manchester M13 9PL UK
| | - Paulo Bártolo
- Department of Mechanical, Aerospace and Civil Engineering, School of Engineering, Faculty of Science and Engineering, University of Manchester Manchester M13 9PL UK
| | - Mark Dickinson
- Photon Science Institute, University of Manchester Oxford Road Manchester M13 9PL UK
| | - Brian R Saunders
- Department of Materials, University of Manchester, MSS Tower Manchester M13 9PL UK
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9
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Cheng FM, Chen HX, Li HD. Recent advances in tough and self-healing nanocomposite hydrogels for shape morphing and soft actuators. Eur Polym J 2020. [DOI: 10.1016/j.eurpolymj.2019.109448] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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10
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Wu S, Zhu M, Lu D, Milani AH, Lian Q, Fielding LA, Saunders BR, Derry MJ, Armes SP, Adlam D, Hoyland JA. Self-curing super-stretchable polymer/microgel complex coacervate gels without covalent bond formation. Chem Sci 2019; 10:8832-8839. [PMID: 31803457 PMCID: PMC6849882 DOI: 10.1039/c9sc02555c] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2019] [Accepted: 08/02/2019] [Indexed: 12/25/2022] Open
Abstract
Elastic physical gels are highly desirable because they can be conveniently prepared and readily shaped. Unfortunately, many elastic physical gels prepared in water require in situ free-radical polymerization during the gel formation stage. In contrast, complex coacervate gels are physical gels that can be prepared by simply mixing two pre-formed oppositely-charged polyelectrolytes. However, as far as we are aware, highly elastic complex coacervate gels have not yet been reported. Herein, we combine polyanionic microgel particles with a well-known commercially-available cationic polyelectrolyte to prepare polymer/microgel complex coacervate (PMCC) physical gels. This new family of gels requires annealing at only 37 °C and behaves like a covalent gel but does not form covalent bonds. Thermal reconfiguration of the dynamic ionic bonds transforms the shapeable pre-gel into a highly elastic gel that is super-stretchable, adhesive, self-healing, highly swellable and can be further toughened using Ca2+ as an ionic crosslinker. Our PMCC gels have excellent potential for applications as engineering gels and structural biomaterials, as well as for wound healing and water purification.
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Affiliation(s)
- Shanglin Wu
- School of Materials , University of Manchester , MSS Tower , Manchester , M13 9PL , UK . ;
| | - Mingning Zhu
- School of Materials , University of Manchester , MSS Tower , Manchester , M13 9PL , UK . ;
| | - Dongdong Lu
- School of Materials , University of Manchester , MSS Tower , Manchester , M13 9PL , UK . ;
| | - Amir H Milani
- School of Materials , University of Manchester , MSS Tower , Manchester , M13 9PL , UK . ;
| | - Qing Lian
- School of Materials , University of Manchester , MSS Tower , Manchester , M13 9PL , UK . ;
| | - Lee A Fielding
- School of Materials , University of Manchester , MSS Tower , Manchester , M13 9PL , UK . ;
| | - Brian R Saunders
- School of Materials , University of Manchester , MSS Tower , Manchester , M13 9PL , UK . ;
| | - Matthew J Derry
- Department of Chemistry , The University of Sheffield , Dainton Building, Brook Hill , Sheffield , South Yorkshire S3 7HF , UK
| | - Steven P Armes
- Department of Chemistry , The University of Sheffield , Dainton Building, Brook Hill , Sheffield , South Yorkshire S3 7HF , UK
| | - Daman Adlam
- Division of Cell Matrix Biology and Regenerative Medicine , Faculty of Biology, Medicine and Health , University of Manchester , Oxford Road , Manchester , M13 9PT , UK
| | - Judith A Hoyland
- Division of Cell Matrix Biology and Regenerative Medicine , Faculty of Biology, Medicine and Health , University of Manchester , Oxford Road , Manchester , M13 9PT , UK
- NIHR Manchester Biomedical Research Centre , Central Manchester Foundation Trust , Manchester Academic Health Science Centre , Manchester , M13 9WL , UK
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11
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Shanks HR, Milani AH, Lu D, Saunders BR, Carney L, Adlam DJ, Hoyland JA, Blount C, Dickinson M. Core-Shell-Shell Nanoparticles for NIR Fluorescence Imaging and NRET Swelling Reporting of Injectable or Implantable Gels. Biomacromolecules 2019; 20:2694-2702. [PMID: 31185170 PMCID: PMC7007186 DOI: 10.1021/acs.biomac.9b00463] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Revised: 05/31/2019] [Indexed: 11/29/2022]
Abstract
Injectable gels that support load are desirable for restoring the mechanical properties of degenerated load-bearing tissue. As these gels become increasingly sophisticated, the need to remotely image them and monitor their swelling increases. However, imaging such gels and monitoring their swelling using noninvasive means is challenging. Here, we use a very low concentration of near-infrared (NIR) core-shell-shell (CSS) reporter nanoparticles to both image and monitor swelling changes of two load-supporting gels. The load-supporting injectable gel consisted of covalently interlinked pH-responsive microgel (MG) particles. The latter gel was not cytotoxic and is termed a doubly cross-linked microgel (DX MG). Inclusion of a complementary fluorescent dye enabled ratiometric monitoring of gel swelling changes in response to pH via nonradiative resonance energy transfer (NRET). In addition, changes in the CSS nanoparticle emission intensity provided a NIR-only method that could also be used to monitor gel swelling. The gel was able to be imaged using NIR light, after being subcutaneously injected into a tissue model. To demonstrate versatility of our approach, CSS and the dye were included within a model implantable gel (poly(acrylamide/acrylic acid)) and fluorescent detection of swelling investigated. Because the concentrations of the reporting species were too low to affect the mechanical properties, our approach to remote gel imaging and swelling monitoring has good potential for application in injectable gels and implants.
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Affiliation(s)
- Hannah R. Shanks
- School
of Materials, University of Manchester, MSS Tower, Manchester, M13 9PL, U.K.
| | - Amir H. Milani
- School
of Materials, University of Manchester, MSS Tower, Manchester, M13 9PL, U.K.
| | - Dongdong Lu
- School
of Materials, University of Manchester, MSS Tower, Manchester, M13 9PL, U.K.
| | - Brian R. Saunders
- School
of Materials, University of Manchester, MSS Tower, Manchester, M13 9PL, U.K.
| | - Louise Carney
- School
of Materials, University of Manchester, MSS Tower, Manchester, M13 9PL, U.K.
| | - Daman J. Adlam
- Division
of Cell Matrix Biology and Regenerative Medicine, Faculty of Biology,
Medicine and Health, University of Manchester, Oxford Road, Manchester, M13 9PT, U.K.
| | - Judith A. Hoyland
- Division
of Cell Matrix Biology and Regenerative Medicine, Faculty of Biology,
Medicine and Health, University of Manchester, Oxford Road, Manchester, M13 9PT, U.K.
- NIHR
Manchester Biomedical Research Centre, Manchester University NHS Foundation
Trust, Manchester Academic Health Science
Centre, Manchester, M20 2LR, U.K.
| | - Christopher Blount
- Photon
Science Institute, University of Manchester, Oxford Road, Manchester, M13 9PL, U.K.
- School
of Physics & Astronomy, University of
Manchester, Oxford Road, Manchester, M13 9PL, U.K.
| | - Mark Dickinson
- Photon
Science Institute, University of Manchester, Oxford Road, Manchester, M13 9PL, U.K.
- School
of Physics & Astronomy, University of
Manchester, Oxford Road, Manchester, M13 9PL, U.K.
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12
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Azimi Dijvejin Z, Ghaffarkhah A, Vafaie Sefti M, Moraveji MK. Synthesis, structure and mechanical properties of nanocomposites based on exfoliated nano magnesium silicate crystal and poly(acrylamide). J DISPER SCI TECHNOL 2018. [DOI: 10.1080/01932691.2018.1467777] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Affiliation(s)
- Zahra Azimi Dijvejin
- Department of Petroleum Engineering Faculty of Chemical Engineering, Tarbiat Modares University, Tehran, Iran
| | - Ahmadreza Ghaffarkhah
- Department of petroleum engineering, Amirkabir University of Technology (Tehran Polytechnic), Tehran, Iran
- Research Institute of Petroleum Industry (RIPI), Tehran, Iran
| | - Mohsen Vafaie Sefti
- Department of Chemical Engineering, Faculty of Chemical Engineering, Tarbiat Modares University, Tehran, Iran
| | - Mostafa Keshavarz Moraveji
- Department of Chemical Engineering, Amirkabir University of Technology (Tehran Polytechnic), Tehran, Iran
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13
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Wang W, Lu D, Zhu M, Saunders JM, Milani AH, Armes SP, Saunders BR. Highly deformable hydrogels constructed by pH-triggered polyacid nanoparticle disassembly in aqueous dispersions. SOFT MATTER 2018; 14:3510-3520. [PMID: 29671461 DOI: 10.1039/c8sm00325d] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Most hydrogels are prepared using small-molecule monomers but unfortunately this approach may not be feasible for certain biomaterial applications. Consequently, alternative gel construction strategies have been established, which include using covalent inter-linking of preformed gel particles, or microgels (MGs). For example, covalently interlinking pH-responsive MGs can produce hydrogels comprising doubly crosslinked microgels (DX MGs). We hypothesised that the deformability of such DX MGs was limited by the presence of intra-MG crosslinking. Thus, in this study we designed new nanoparticle (NP)-based gels based on pH-swellable NPs that are not internally crosslinked. Two polyacid NPs were synthesised containing methacrylic acid (MAA) and either ethyl acrylate (EA) or methyl methacrylate (MMA). The PMAA-EA and PMAA-MMA NPs were subsequently vinyl-functionalised using glycidyl methacrylate (GMA) prior to gel formation via free-radical crosslinking. The NPs mostly disassembled on raising the solution pH but some self-crosslinking was nevertheless evident. The gels constructed from the EA- and MMA-based NPs had greater breaking strains than a control DX MG. The effect of varying the solution pH during curing on the morphology and mechanical properties of gels prepared using PMAA-MMA-GMA NPs was studied and both remarkable deformability and excellent recovery were observed. The gels were strongly pH-responsive and had tensile breaking strains of up to 420% with a compressive strain-at-break of more than 93%. An optimised formulation produced the most deformable and stretchable gel yet constructed using NPs or MGs as the only building block.
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Affiliation(s)
- Wenkai Wang
- School of Materials, University of Manchester, MSS Tower, Manchester, M13 9PL, UK.
| | - Dongdong Lu
- School of Materials, University of Manchester, MSS Tower, Manchester, M13 9PL, UK.
| | - Mingning Zhu
- School of Materials, University of Manchester, MSS Tower, Manchester, M13 9PL, UK.
| | - Jennifer M Saunders
- School of Materials, University of Manchester, MSS Tower, Manchester, M13 9PL, UK.
| | - Amir H Milani
- School of Materials, University of Manchester, MSS Tower, Manchester, M13 9PL, UK.
| | - Steven P Armes
- Department of Chemistry, The University of Sheffield, Dainton Building, Brook Hill, Sheffield, South Yorkshire S3 7HF, UK
| | - Brian R Saunders
- School of Materials, University of Manchester, MSS Tower, Manchester, M13 9PL, UK.
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14
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Milani AH, Saunders JM, Nguyen NT, Ratcliffe LPD, Adlam DJ, Freemont AJ, Hoyland JA, Armes SP, Saunders BR. Synthesis of polyacid nanogels: pH-responsive sub-100 nm particles for functionalisation and fluorescent hydrogel assembly. SOFT MATTER 2017; 13:1554-1560. [PMID: 28120992 DOI: 10.1039/c6sm02713j] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Nanogels are crosslinked polymer particles with a swollen size between 1 and 100 nm. They are of major interest for advanced surface coatings, drug delivery, diagnostics and biomaterials. Synthesising polyacid nanogels that show triggered swelling using a scalable approach is a key objective of polymer colloid chemistry. Inspired by the ability of polar surfaces to enhance nanoparticle stabilisation, we report the first examples of pH-responsive polyacid nanogels containing high -COOH contents prepared by a simple, scalable, aqueous method. To demonstrate their functionalisation potential, glycidyl methacrylate was reacted with the -COOH chemical handles and the nanogels were converted to macro-crosslinkers. The concentrated (functionalised) nanogel dispersions retained their pH-responsiveness, were shear-thinning and formed physical gels at pH 7.4. The nanogels were covalently interlinked via free-radical coupling at 37 °C to form transparent, ductile, hydrogels. Mixing of the functionalised nanogels with polymer dots enabled covalent assembly of fluorescent hydrogels.
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Affiliation(s)
- Amir H Milani
- School of Materials, University of Manchester, Manchester, M13 9PL, UK.
| | | | - Nam T Nguyen
- School of Materials, University of Manchester, Manchester, M13 9PL, UK.
| | - Liam P D Ratcliffe
- Department of Chemistry, The University of Sheffield, Dainton Building, Brook Hill, Sheffield, South Yorkshire S3 7HF, UK
| | - Daman J Adlam
- Division of Cell Matrix Biology and Regenerative Medicine, Faculty of Biology, Medicine and Health, University of Manchester, Oxford Road, Manchester, M13 9PL, UK
| | - Anthony J Freemont
- Division of Cell Matrix Biology and Regenerative Medicine, Faculty of Biology, Medicine and Health, University of Manchester, Oxford Road, Manchester, M13 9PL, UK
| | - Judith A Hoyland
- Division of Cell Matrix Biology and Regenerative Medicine, Faculty of Biology, Medicine and Health, University of Manchester, Oxford Road, Manchester, M13 9PL, UK and NIHR Manchester Musculoskeletal Biomedical Research Unit, Manchester Academic Health Science Centre, Manchester, UK
| | - Steven P Armes
- Department of Chemistry, The University of Sheffield, Dainton Building, Brook Hill, Sheffield, South Yorkshire S3 7HF, UK
| | - Brian R Saunders
- School of Materials, University of Manchester, Manchester, M13 9PL, UK.
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Schmidt MM, Wu S, Cui Z, Nguyen NT, Faulkner M, Saunders BR. How gold nanoparticles can be used to probe the structural changes of a pH-responsive hydrogel. Phys Chem Chem Phys 2017; 19:5102-5112. [PMID: 28138660 DOI: 10.1039/c6cp07929f] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Gold nanoparticles (GNPs) have UV-visible absorption spectra that are highly sensitive to their local environment due to their surface plasmon resonance (SPR). Furthermore, GNPs are able to quench the fluorescence of suitable dyes depending on the GNP-dye separation. Both of these features have led to the use of GNPs as spectroscopic rulers. In this study we sought to use GNPs as spectroscopic probes to investigate the local structural changes associated with the macroscopic pH-triggered swelling/de-swelling transitions of a pH-responsive hydrogel. The hydrogel used in this study comprised covalently inter-linked pH-responsive poly(ethylacrylate-co-methacrylic acid-co-divinyl benzene) microgel particles (MGs). MGs are crosslinked polymer colloids that swell when the pH approaches the pKa of the constituent polymer. The interlinked MG hydrogels are termed doubly crosslinked microgels (DX MGs) and are a new family of hydrogels. They had polymer volume fractions (ϕp) that strongly decreased as the pH increased. UV-visible spectra showed that the wavelength of the SPR absorption (λmax) for the DX MG/GNP gels was pH-responsive. A linear relationship was found between λmax and ϕp for ϕp values up to ∼0.80. The inclusion of Rhodamine 6G within the DX MG/GNP hydrogels resulted in metal-induced fluorescence quenching which was studied using photoluminescence (PL) spectroscopy. The extent of quenching was pH-dependent and was also proportional to ϕp. The results of the study showed that the pH-triggered changes of the nanoscale and macroscopic swelling for the DX MGs were similar and imply that affine swelling occurred, which is a new observation. The data suggest that UV-visible or PL spectroscopy could be used to study the swelling of pH-responsive hydrogels containing GNPs remotely.
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Affiliation(s)
- Maximilian M Schmidt
- School of Materials, MSS Tower, The University of Manchester, Manchester, M13 9PL, UK. and Institute of Physical Chemistry, RWTH Aachen University, Landoltweg 2, D-52056, Aachen, Germany
| | - Shanglin Wu
- School of Materials, MSS Tower, The University of Manchester, Manchester, M13 9PL, UK.
| | - Zhengxing Cui
- School of Materials, MSS Tower, The University of Manchester, Manchester, M13 9PL, UK.
| | - Nam T Nguyen
- School of Materials, MSS Tower, The University of Manchester, Manchester, M13 9PL, UK.
| | - Michael Faulkner
- School of Materials, MSS Tower, The University of Manchester, Manchester, M13 9PL, UK.
| | - Brian R Saunders
- School of Materials, MSS Tower, The University of Manchester, Manchester, M13 9PL, UK.
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