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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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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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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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