1
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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] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [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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2
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Zhu M, Lu D, Milani AH, Mahmoudi N, King SM, Saunders BR. Comparing pH-responsive nanogel swelling in dispersion and inside a polyacrylamide gel using photoluminescence spectroscopy and small-angle neutron scattering. J Colloid Interface Sci 2022; 608:378-385. [PMID: 34626983 DOI: 10.1016/j.jcis.2021.09.163] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Revised: 09/18/2021] [Accepted: 09/26/2021] [Indexed: 10/20/2022]
Abstract
Nanosized probes that report their changes in dimensions within networks in response to environmental stimuli are potentially important for applications such as drug delivery, load-supporting hydrogels and soft robotics. Recently, we developed a fluorescent pH-responsive nanogel (NG) that used Förster-resonance energy transfer (FRET) to report changes in the probe separation and NG swelling within hydrogels using photoluminescence (PL) spectroscopy. However, FRET cannot measure nanoparticle dimensions and is subject to artefacts. Here, we report the use of small-angle neutron scattering (SANS) to study both the NGs in dispersion and in polyacrylamide (PAAm) gels as a function of pH. We compare the PL and SANS data for both systems and as a function of pH. The SANS data for the dispersed NGs indicate that they have a core-shell structure with a swollen mesh size of ∼1.0 nm. We hypothesized that the NGs inside the PAAm gel would show the same general changes in scattering as the pH is increased, as observed for the dispersed NGs, and this is confirmed by the data. In summary, the data confirm that PL is a suitable (accessible) method for reporting internal environmental changes within gels using NG probes.
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Affiliation(s)
- 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
| | - Najet Mahmoudi
- ISIS Facility, STFC, Rutherford Appleton Laboratory, Harwell Campus, Didcot OX11 0QX, UK
| | - Stephen M King
- ISIS Facility, STFC, Rutherford Appleton Laboratory, Harwell Campus, Didcot OX11 0QX, UK
| | - Brian R Saunders
- School of Materials, University of Manchester, MSS Tower, Manchester M13 9PL, UK
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3
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Altujjar A, Mokhtar MZ, Chen Q, Neilson J, Spencer BF, Thomas A, Saunders JM, Wang R, Alkhudhari O, Mironov A, Saunders BR. Improving the Efficiency, Stability, and Adhesion of Perovskite Solar Cells Using Nanogel Additive Engineering. ACS APPLIED MATERIALS & INTERFACES 2021; 13:58640-58651. [PMID: 34859674 DOI: 10.1021/acsami.1c18239] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Additive engineering has been applied widely to improve the efficiency and/or stability of perovskite solar cells (PSCs). Most additives used to date are difficult to locate within PSCs as they are small molecules or linear polymers. In this work, we introduce, for the first time, carboxylic acid-functionalized nanogels (NGs) as additives for PSCs. NGs are swellable sub-100 nm gel particles. The NGs consist of poly(2-(2-methoxyethoxy) ethyl methacrylate)-co-methacrylic acid-co-ethylenegylcol dimethacrylate (PMEO2MA-MAA-EGD) particles prepared by a scalable synthesis, which have a diameter of 40 nm. They are visualized in the perovskite films using SEM and are located at the grain boundaries. X-ray photoelectron and FTIR spectroscopy reveal that the NGs coordinate with Pb2+ via the -COOH groups. Including the NGs within the PSCs increased the grain size, decreased nonradiative recombination, and increased the power conversion efficiency (PCE) to 20.20%. The NGs also greatly increase perovskite stability to ambient storage, elevated temperature, and humidity. The best system maintained more than 80% of its original PCE after 180 days of storage under ambient conditions. Tensile cross-cut tape adhesion tests are used to assess perovskite film mechanical integrity. The NGs increased both the adhesion of the perovskite to the substrate and the mechanical stability. This study demonstrates that NGs are an attractive alternative to molecularly dispersed additives for providing performance benefits to PSCs. Our study indicates that the NGs act as a passivator, stabilizer, cross-linker, and adhesion promoter.
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Affiliation(s)
- Amal Altujjar
- 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
| | - Qian Chen
- Department of Materials, University of Manchester, MSS Tower, Manchester M13 9PL, U.K
| | - Joseph Neilson
- Department of Materials, University of Manchester, MSS Tower, Manchester M13 9PL, U.K
| | - Ben F Spencer
- Department of Materials, University of Manchester, MSS Tower, Manchester M13 9PL, U.K
- The Photon Science Institute and The Henry Royce Institute, University of Manchester, Alan Turing Building, Oxford Road, Manchester M13 9PL, U.K
| | - Andrew Thomas
- Department of Materials, University of Manchester, MSS Tower, Manchester M13 9PL, U.K
- The Photon Science Institute and The Henry Royce Institute, University of Manchester, Alan Turing Building, Oxford Road, Manchester M13 9PL, U.K
| | - Jennifer M Saunders
- Department of Materials, University of Manchester, MSS Tower, Manchester M13 9PL, U.K
| | - Ran Wang
- Department of Materials, University of Manchester, MSS Tower, Manchester M13 9PL, U.K
| | - Osama Alkhudhari
- Department of Materials, University of Manchester, MSS Tower, Manchester M13 9PL, U.K
| | - Aleksandr Mironov
- EM Core Facility (RRID: SCR_021147), Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PT, U.K
| | - Brian R Saunders
- Department of Materials, University of Manchester, MSS Tower, Manchester M13 9PL, U.K
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4
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Schneider S, Jung F, Mergel O, Lammertz J, Nickel AC, Caumanns T, Mhamdi A, Mayer J, Mitsos A, Plamper FA. Model-based design and synthesis of ferrocene containing microgels. Polym Chem 2020. [DOI: 10.1039/c9py00494g] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Modelling and synthesis go hand in hand to efficiently engineer copolymer microgels with various architectures: core–shell structures (with ferrocene mainly in the core or in the shell) and also microgels with homogeneous comonomer distribution.
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Affiliation(s)
- Sabine Schneider
- Institute of Physical Chemistry
- RWTH Aachen University
- 52056 Aachen
- Germany
| | - Falco Jung
- Aachener Verfahrenstechnik
- Process Systems Engineering
- RWTH Aachen University
- 52074 Aachen
- Germany
| | - Olga Mergel
- Department of Biomedical Engineering-FB40
- University of Groningen
- University Medical Center Groningen
- Groningen
- The Netherlands
| | - Janik Lammertz
- Institute of Physical Chemistry
- RWTH Aachen University
- 52056 Aachen
- Germany
| | - Anne C. Nickel
- Institute of Physical Chemistry
- RWTH Aachen University
- 52056 Aachen
- Germany
| | - Tobias Caumanns
- GFE Central Facility for Electron Microscopy
- RWTH Aachen University
- 52074 Aachen
- Germany
| | - Adel Mhamdi
- Aachener Verfahrenstechnik
- Process Systems Engineering
- RWTH Aachen University
- 52074 Aachen
- Germany
| | - Joachim Mayer
- GFE Central Facility for Electron Microscopy
- RWTH Aachen University
- 52074 Aachen
- Germany
| | - Alexander Mitsos
- Aachener Verfahrenstechnik
- Process Systems Engineering
- RWTH Aachen University
- 52074 Aachen
- Germany
| | - Felix A. Plamper
- Institute of Physical Chemistry
- RWTH Aachen University
- 52056 Aachen
- Germany
- Institute of Physical Chemistry
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5
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Zhu M, Lu D, Wu S, Lian Q, Wang W, Lyon LA, Wang W, Bártolo P, Saunders BR. Using green emitting pH-responsive nanogels to report environmental changes within hydrogels: a nanoprobe for versatile sensing. NANOSCALE 2019; 11:11484-11495. [PMID: 31066411 DOI: 10.1039/c9nr00989b] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Remotely reporting the local environment within hydrogels using inexpensive laboratory techniques has excellent potential to improve our understanding of the nanometer-scale changes that cause macroscopic swelling or deswelling. Whilst photoluminescence (PL) spectroscopy is a popular method for such studies this approach commonly requires bespoke and time-consuming synthesis to attach fluorophores which may leave toxic residues. A promising and more versatile alternative is to use a pre-formed nanogel probe that contains a donor/acceptor pair and then "dope" that into the gel during gel assembly. Here, we introduce green-emitting methacrylic acid-based nanogel probe particles and use them to report the local environment within four different gels as well as stem cells. As the swelling of the nanogel probe changes within the gels the non-radiative energy transfer efficiency is strongly altered. This efficiency change is sensitively reported using the PL ratiometric intensity from the donor and acceptor. We demonstrate that our new nanoprobes can reversibly report gel swelling changes due to five different environmental stimuli. The latter are divalent cations, gel degradation, pH changes, temperature changes and tensile strain. In the latter case, the nanoprobe rendered a nanocomposite gel mechanochromic. The results not only provide new structural insights for hierarchical natural and synthetic gels, but also demonstrate that our new green-fluorescing nanoprobes provide a viable alternative to custom fluorophore labelling for reporting the internal gel environment and its changes.
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Affiliation(s)
- Mingning Zhu
- School of Materials, University of Manchester, MSS Tower, Manchester, M13 9PL, UK.
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6
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Nguyen NT, Milani AH, Jennings J, Adlam DJ, Freemont AJ, Hoyland JA, Saunders BR. Highly compressive and stretchable poly(ethylene glycol) based hydrogels synthesised using pH-responsive nanogels without free-radical chemistry. NANOSCALE 2019; 11:7921-7930. [PMID: 30964497 DOI: 10.1039/c9nr01535c] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Poly(ethylene glycol) (PEG) based hydrogels are amongst the most studied synthetic hydrogels. However, reports on PEG-based hydrogels with high mechanical strength are limited. Herein, a class of novel, well-defined PEG-based nanocomposite hydrogels with tunable mechanical strength are synthesised via ring-opening reactions of diglycidyl ethers with carboxylate ions. The pH responsive crosslinked polyacid nanogels (NG) in the dispersed phase act as high functionality crosslinkers which covalently bond to the poly(ethylene glycol) diglycidyl ethers (PEGDGE) as the continuous matrix. A series of NG-x-PEG-y-z gels are prepared where x, y and z are concentrations of NGs, PEGDGE and the PEGDGE molecular weight, respectively. The hydrogel compositions and nano-structural homogeneity of the NGs have strong impact on the enhancement of mechanical properties which enables property tuning. Based on this design, a highly compressive PEG-based nanocomposite hydrogel (NG-13-PEG-20-6000) exhibits a compressive stress of 24.2 MPa, compressive fracture strain greater than 98% and a fracture energy density as high as 1.88 MJ m-3. The tensile fracture strain is 230%. This is amongst one of the most compressive PEG-based hydrogels reported to-date. Our chemically crosslinked gels are resilient and show highly recoverable dissipative energy. The cytotoxicity test shows that human nucleus pulposus (NP) cells remained viable after 8 days of culture time. The overall results highlight their potential for applications as replacements for intervertebral discs or articular cartilages.
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Affiliation(s)
- Nam T Nguyen
- School of Materials, University of Manchester, Manchester, M13 9PL, UK.
| | - Amir H Milani
- School of Materials, University of Manchester, Manchester, M13 9PL, UK.
| | - James Jennings
- Department of Chemistry, University of Sheffield, 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 9PT, 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 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 and NIHR Manchester Biomedical Research Centre, Manchester University NHS foundation Trust, Manchester Academic Health Science Centre, M13 9WL, UK
| | - Brian R Saunders
- School of Materials, University of Manchester, Manchester, M13 9PL, UK.
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7
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Wang H, Chen Q, Zhou S. Carbon-based hybrid nanogels: a synergistic nanoplatform for combined biosensing, bioimaging, and responsive drug delivery. Chem Soc Rev 2018; 47:4198-4232. [PMID: 29667656 DOI: 10.1039/c7cs00399d] [Citation(s) in RCA: 135] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Nanosized crosslinked polymer networks, named as nanogels, are playing an increasingly important role in a diverse range of applications by virtue of their porous structures, large surface area, good biocompatibility and responsiveness to internal and/or external chemico-physical stimuli. Recently, a variety of carbon nanomaterials, such as carbon quantum dots, graphene/graphene oxide nanosheets, fullerenes, carbon nanotubes, and nanodiamonds, have been embedded into responsive polymer nanogels, in order to integrate the unique electro-optical properties of carbon nanomaterials with the merits of nanogels into a single hybrid nanogel system for improvement of their applications in nanomedicine. A vast number of studies have been pursued to explore the applications of carbon-based hybrid nanogels in biomedical areas for biosensing, bioimaging, and smart drug carriers with combinatorial therapies and/or theranostic ability. New synthetic methods and structures have been developed to prepare carbon-based hybrid nanogels with versatile properties and functions. In this review, we summarize the latest developments and applications and address the future perspectives of these carbon-based hybrid nanogels in the biomedical field.
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Affiliation(s)
- Hui Wang
- High Magnetic Field Laboratory, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, 230031, Anhui, P. R. China.
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8
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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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9
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Zhu M, Lu D, Wu S, Lian Q, Wang W, Milani AH, Cui Z, Nguyen NT, Chen M, Lyon LA, Adlam DJ, Freemont AJ, Hoyland JA, Saunders BR. Responsive Nanogel Probe for Ratiometric Fluorescent Sensing of pH and Strain in Hydrogels. ACS Macro Lett 2017; 6:1245-1250. [PMID: 35650778 DOI: 10.1021/acsmacrolett.7b00709] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In this study a new pH-responsive nanogel probe containing a complementary nonradiative resonance energy transfer (NRET) fluorophore pair is investigated and its ability to act as a versatile probe of network-related changes in three hydrogels demonstrated. Fluorescent sensing using NRET is a powerful method for studying relationships between Angstrom length-scale structure and macroscopic properties of soft matter. Unfortunately, inclusion of NRET fluorophores into such materials requires material-specific chemistry. Here, low concentrations of preformed nanogel probes were included into hydrogel hosts. Ratiometric photoluminescence (PL) data for the gels labeled with the nanogel probes enabled pH-triggered swelling and deswelling to be studied as well as Ca2+-triggered collapse and solute release. PL measurements during compression of a nanogel probe-labeled nanocomposite gel demonstrated mechanochromic behavior and strain sensing. The new nanogel probes have excellent potential for investigating the internal structures of gels and provide a versatile ratiometric fluorescent platform for studying pH and strain.
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Affiliation(s)
- Mingning Zhu
- 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
| | - Shanglin Wu
- School
of Materials, University of Manchester, MSS Tower, Manchester M13 9PL, U.K
| | - Qing Lian
- School
of Materials, University of Manchester, MSS Tower, Manchester M13 9PL, U.K
| | - Wenkai Wang
- 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
| | - Zhengxing Cui
- School
of Materials, University of Manchester, MSS Tower, Manchester M13 9PL, U.K
| | - Nam T. Nguyen
- School
of Materials, University of Manchester, MSS Tower, Manchester M13 9PL, U.K
| | - Mu Chen
- School
of Materials, University of Manchester, MSS Tower, Manchester M13 9PL, U.K
| | - L. Andrew Lyon
- Schmid
College of Science and Technology, Chapman University, Orange, California 92866, United States
| | - 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
| | - Anthony J. Freemont
- 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 Musculoskeletal Biomedical Research Unit, Central Manchester
Foundation Trust, Manchester Academic Health Science Centre, Manchester, 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 Musculoskeletal Biomedical Research Unit, Central Manchester
Foundation Trust, Manchester Academic Health Science Centre, Manchester, U.K
| | - Brian R. Saunders
- School
of Materials, University of Manchester, MSS Tower, Manchester M13 9PL, U.K
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10
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Wang W, Milani AH, Cui Z, Zhu M, Saunders BR. Pickering Emulsions Stabilized by pH-Responsive Microgels and Their Scalable Transformation to Robust Submicrometer Colloidoisomes with Selective Permeability. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:8192-8200. [PMID: 28749692 DOI: 10.1021/acs.langmuir.7b01618] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Colloidosomes are micrometer-sized hollow particles that have shells consisting of coagulated or fused colloid particles. While many large colloidosomes with sizes well above 1.0 μm have been prepared, there are fewer examples of submicrometer colloidosomes. Here, we establish a simple emulsion templating-based method for the preparation of robust submicrometer pH-responsive microgel colloidosomes. The colloidosomes are constructed from microgel particles based on ethyl acrylate and methacrylic acid with peripheral vinyl groups. The pH-responsive microgels acted as both a Pickering emulsion stabilizer and macro-cross-linker. The emulsion formation studies showed that the minimum droplet diameter was reached when the microgel particles were partially swollen. Microgel colloidosomes were prepared by covalently interlinking the microgels adsorbed at the oil-water interface using thermal free-radical coupling. The colloidosomes were prepared using a standard high-shear mixer with two different rotor sizes that corresponded to high shear (HS) and very high shear (VHS) mixing conditions. The latter enabled the construction of submicrometer pH-responsive microgel-colloidosomes on the gram scale. The colloidosomes swelled strongly when the pH increased to above 6.0. The colloidosomes were robust and showed no evidence of colloidosome breakup at high pH. The effect of solute size on shell permeation was studied using a range of FITC-dextran polymers, and size-selective permeation occurred. The average pore size of the VHS microgel-colloidosomes was estimated to be between 6.6 and 9.0 nm at pH 6.2. The microgel-colloidosome properties suggest that they have the potential for future applications in cosmetics, photonics, and delivery.
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Affiliation(s)
- Wenkai Wang
- Polymers and Composites Group, School of Materials, The University of Manchester , MSS Tower, Manchester M13 9PL, U.K
| | - Amir H Milani
- Polymers and Composites Group, School of Materials, The University of Manchester , MSS Tower, Manchester M13 9PL, U.K
| | - Zhengxing Cui
- Polymers and Composites Group, School of Materials, The University of Manchester , MSS Tower, Manchester M13 9PL, U.K
| | - Mingning Zhu
- Polymers and Composites Group, School of Materials, The University of Manchester , MSS Tower, Manchester M13 9PL, U.K
| | - Brian R Saunders
- Polymers and Composites Group, School of Materials, The University of Manchester , MSS Tower, Manchester M13 9PL, U.K
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