1
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Liu Y, Li L, Li X, Cherif H, Jiang S, Ghezelbash F, Weber MH, Juncker D, Li-Jessen NYK, Haglund L, Li J. Viscoelastic hydrogels regulate adipose-derived mesenchymal stem cells for nucleus pulposus regeneration. Acta Biomater 2024; 180:244-261. [PMID: 38615812 DOI: 10.1016/j.actbio.2024.04.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 04/05/2024] [Accepted: 04/09/2024] [Indexed: 04/16/2024]
Abstract
Low back pain is a leading cause of disability worldwide, often attributed to intervertebral disc (IVD) degeneration with loss of the functional nucleus pulposus (NP). Regenerative strategies utilizing biomaterials and stem cells are promising for NP repair. Human NP tissue is highly viscoelastic, relaxing stress rapidly under deformation. However, the impact of tissue-specific viscoelasticity on the activities of adipose-derived stem cells (ASC) remains largely unexplored. Here, we investigated the role of matrix viscoelasticity in regulating ASC differentiation for IVD regeneration. Viscoelastic alginate hydrogels with stress relaxation time scales ranging from 100 s to 1000s were developed and used to culture human ASCs for 21 days. Our results demonstrated that the fast-relaxing hydrogel significantly enhanced ASCs long-term cell survival and NP-like extracellular matrix secretion of aggrecan and type-II collagen. Moreover, gene expression analysis revealed a substantial upregulation of the mechanosensitive ion channel marker TRPV4 and NP-specific markers such as SOX9, HIF-1α, KRT18, CDH2 and CD24 in ASCs cultured within the fast-relaxing hydrogel, compared to slower-relaxing hydrogels. These findings highlight the critical role of matrix viscoelasticity in regulating ASC behavior and suggest that viscoelasticity is a key parameter for novel biomaterials design to improve the efficacy of stem cell therapy for IVD regeneration. STATEMENT OF SIGNIFICANCE: Systematically characterized the influence of tissue-mimetic viscoelasticity on ASC. NP-mimetic hydrogels with tunable viscoelasticity and tissue-matched stiffness. Long-term survival and metabolic activity of ASCs are substantially improved in the fast-relaxing hydrogel. The fast-relaxing hydrogel allows higher rate of cell protrusions formation and matrix remodeling. ASC differentiation towards an NP-like cell phenotype is promoted in the fast-relaxing hydrogel, with more CD24 positive expression indicating NP committed cell fate. The expression of TRPV4, a molecular sensor of matrix viscoelasticity, is significantly enhanced in the fast-relaxing hydrogel, indicating ASC sensing matrix viscoelasticity during cell development. The NP-specific ECM secretion of ASC is considerably influenced by matrix viscoelasticity, where the deposition of aggrecan and type-II collagen are significantly enhanced in the fast-relaxing hydrogel.
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Affiliation(s)
- Yin Liu
- Department of Biomedical Engineering, McGill University, 3775 Rue University, Montréal, QC H3A 2B4, Canada; Department of Mechanical Engineering, McGill University, 817 Sherbrooke Street West, Montréal, QC H3A 0C3, Canada
| | - Li Li
- Department of Surgery, McGill University, 1650 Cedar Avenue, Montréal, QC H3G 1A4, Canada
| | - Xuan Li
- Department of Mechanical Engineering, McGill University, 817 Sherbrooke Street West, Montréal, QC H3A 0C3, Canada
| | - Hosni Cherif
- Department of Surgery, McGill University, 1650 Cedar Avenue, Montréal, QC H3G 1A4, Canada
| | - Shuaibing Jiang
- Department of Mechanical Engineering, McGill University, 817 Sherbrooke Street West, Montréal, QC H3A 0C3, Canada
| | - Farshid Ghezelbash
- Department of Mechanical Engineering, McGill University, 817 Sherbrooke Street West, Montréal, QC H3A 0C3, Canada
| | - Michael H Weber
- Department of Surgery, McGill University, 1650 Cedar Avenue, Montréal, QC H3G 1A4, Canada
| | - David Juncker
- Department of Biomedical Engineering, McGill University, 3775 Rue University, Montréal, QC H3A 2B4, Canada; McGill University & Genome Quebec Innovation Centre, 740 Avenue Dr. Penfield, Montréal, QC H4A 0G1, Canada
| | - Nicole Y K Li-Jessen
- Department of Biomedical Engineering, McGill University, 3775 Rue University, Montréal, QC H3A 2B4, Canada; School of Communication Sciences and Disorders, McGill University, 2001 McGill College Avenue, Montréal, QC H3A 1G1, Canada; Department of Otolaryngology - Head and Neck Surgery, McGill University Health Centre, 1001 Bd Décarie, Montréal, QC H4A 3J1, Canada; Research Institute of McGill University Health Center, McGill University, 1001 Bd Décarie, Montréal, QC H4A 3J1, Canada
| | - Lisbet Haglund
- Department of Surgery, McGill University, 1650 Cedar Avenue, Montréal, QC H3G 1A4, Canada; Shriners Hospital for Children, 1003 Bd Décarie, Montréal, QC H4A 0A9, Canada.
| | - Jianyu Li
- Department of Biomedical Engineering, McGill University, 3775 Rue University, Montréal, QC H3A 2B4, Canada; Department of Mechanical Engineering, McGill University, 817 Sherbrooke Street West, Montréal, QC H3A 0C3, Canada; Department of Surgery, McGill University, 1650 Cedar Avenue, Montréal, QC H3G 1A4, Canada.
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2
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Yue Q, Wang S, Jones ST, Fielding LA. Multifunctional Self-Assembled Block Copolymer/Iron Oxide Nanocomposite Hydrogels Formed from Wormlike Micelles. ACS APPLIED MATERIALS & INTERFACES 2024; 16. [PMID: 38592714 PMCID: PMC11056933 DOI: 10.1021/acsami.4c03007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2024] [Revised: 03/25/2024] [Accepted: 03/26/2024] [Indexed: 04/10/2024]
Abstract
This article reports the preparation of multifunctional magnetic nanocomposite hydrogels formed from wormlike micelles. Specifically, iron oxide nanoparticles were incorporated into a temperature responsive block copolymer, poly(glycerol monomethacrylate)-b-poly(2-hydroxypropyl methacrylate) (PGMA-b-PHPMA), and graphene oxide (GO) dispersion at a low temperature (∼2 °C) through high-speed mixing and returning the mixture to room temperature, resulting in the formation of nanocomposite gels. The optimal concentrations of iron oxide and GO enhanced the gel strength of the nanocomposite gels, which exhibited a strong magnetic response when a magnetic field was applied. These materials retained the thermoresponsiveness of the PGMA-PHPMA wormlike micelles allowing for a solid-to-liquid transition to occur when the temperature was reduced. The mechanical and rheological properties and performance of the nanocomposite gels were demonstrated to be adjustable, making them suitable for a wide range of potential applications. These nanocomposite worm gels were demonstrated to be relatively adhesive and to act as strain and temperature sensors, with the measured electrical resistance of the nanocomposite gels changing with applied strain and temperature sweeps. The nanocomposite gels were found to recover efficiently after the application of high shear with approximately 100% healing efficiency within seconds. Additionally, these nanocomposite worm gels were injectable, and the addition of GO and iron oxide nanomaterials seemed to have no significant adverse impact on the biocompatibility of the copolymer gels, making them suitable not only for 3D printing in nanocomposite engineering but also for potential utilization in various biomedical applications as an injectable magnetic responsive hydrogel.
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Affiliation(s)
- Qi Yue
- Department
of Materials, School of Natural Sciences, University of Manchester, Oxford Road, Manchester M13 9PL, U.K.
- Henry
Royce Institute, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K.
| | - Shiyu Wang
- Department
of Materials, School of Natural Sciences, University of Manchester, Oxford Road, Manchester M13 9PL, U.K.
- Henry
Royce Institute, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K.
| | - Samuel T. Jones
- Department
of Materials, School of Natural Sciences, University of Manchester, Oxford Road, Manchester M13 9PL, U.K.
- Henry
Royce Institute, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K.
- School
of Chemistry, University of Birmingham, Edgbaston, Birmingham B15 2TT, U.K.
| | - Lee A. Fielding
- Department
of Materials, School of Natural Sciences, University of Manchester, Oxford Road, Manchester M13 9PL, U.K.
- Henry
Royce Institute, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K.
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3
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Xue X, Wang F, Shi M, Khan FI. Synthesis of Thermo-Responsive Monofunctionalized Diblock Copolymer Worms. Polymers (Basel) 2023; 15:4590. [PMID: 38231987 PMCID: PMC10708438 DOI: 10.3390/polym15234590] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 11/27/2023] [Accepted: 11/29/2023] [Indexed: 01/19/2024] Open
Abstract
Poly(glycerol monomethacrylate)-block-poly(2-hydroxypropyl methacrylate) (PGMA-PHPMA) with worm-like morphology is a typical example of reversible addition-fragmentation chain transfer (RAFT) dispersion polymerized thermo-responsive copolymer via polymerization-induced self-assembly (PISA) in aqueous solution. Chain transfer agents (CTAs) are the key component in controlling RAFT, the structures of which determine the end functional groups of the polymer chain. It is therefore of interest to monofunctionalize the polymers via CTA moiety, for bioactive functionality conjugation and in the meantime maintain the precisely controlled morphology of the copolymers and the related property. In this work, a newly designed CTA 5-(2-(tert-butoxycarbonylamino) ethylamino)-2-cyano-5-oxopentan-2-yl benzodithioate (t-Boc CPDB) was synthesized and used for the RAFT polymerization of PGMA45-PHPMA120. Subsequently, PGMA45-PHPMA120 copolymers with primary amine, maleimide, and reduced L-glutathione (a tripeptide) monofunctionalized terminals were synthesized via deprotection and conjugation reactions. These monofunctionalized copolymers maintain worm-like morphology and thermo-responsive property in aqueous solution (10% w/v), as confirmed by the transmission electron microscopy (TEM) images, and the observation of the phase transition behavior in between 4 °C and room temperature (~20 °C), respectively. Summarily, a range of thermo-responsive monofunctionalized PGMA45-PHPMA120 diblock copolymer worms were successfully synthesized, which are expected to offer potential biomedical applications, such as in polymer therapeutics, drug delivery, and diagnostics.
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Affiliation(s)
- Xuan Xue
- Department of Chemistry, School of Science, Xi’an Jiaotong-Liverpool University, Suzhou 215123, China; (F.W.); (M.S.)
| | - Feifei Wang
- Department of Chemistry, School of Science, Xi’an Jiaotong-Liverpool University, Suzhou 215123, China; (F.W.); (M.S.)
| | - Minhao Shi
- Department of Chemistry, School of Science, Xi’an Jiaotong-Liverpool University, Suzhou 215123, China; (F.W.); (M.S.)
| | - Faez Iqbal Khan
- Department of Biological Sciences, School of Science, Xi’an Jiaotong-Liverpool University, Suzhou 215123, China;
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4
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Zhang QX, Cui M. How to enhance the ability of mesenchymal stem cells to alleviate intervertebral disc degeneration. World J Stem Cells 2023; 15:989-998. [PMID: 38058958 PMCID: PMC10696189 DOI: 10.4252/wjsc.v15.i11.989] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Revised: 09/14/2023] [Accepted: 11/16/2023] [Indexed: 11/24/2023] Open
Abstract
Intervertebral disc (ID) degeneration (IDD) is one of the main causes of chronic low back pain, and degenerative lesions are usually caused by an imbalance between catabolic and anabolic processes in the ID. The environment in which the ID is located is harsh, with almost no vascular distribution within the disc, and the nutrient supply relies mainly on the diffusion of oxygen and nutrients from the blood vessels located under the endplate. The stability of its internal environment also plays an important role in preventing IDD. The main feature of disc degeneration is a decrease in the number of cells. Mesenchymal stem cells have been used in the treatment of disc lesions due to their ability to differentiate into nucleus pulposus cells in a nonspecific anti-inflammatory manner. The main purpose is to promote their regeneration. The current aim of stem cell therapy is to replace the aged and metamorphosed cells in the ID and to increase the content of the extracellular matrix. The treatment of disc degeneration with stem cells has achieved good efficacy, and the current challenge is how to improve this efficacy. Here, we reviewed current treatments for disc degeneration and summarize studies on stem cell vesicles, enhancement of therapeutic effects when stem cells are mixed with related substances, and improvements in the efficacy of stem cell therapy by adjuvants under adverse conditions. We reviewed the new approaches and ideas for stem cell treatment of disc degeneration in order to contribute to the development of new therapeutic approaches to meet current challenges.
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Affiliation(s)
- Qing-Xiang Zhang
- Department of Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, Hubei Province, China
- Department of Critical Care Medicine, Wuhan Jinyintan Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430048, Hubei Province, China
| | - Min Cui
- Department of Orthopedics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, Hubei Province, China.
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5
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Ohnishi T, Homan K, Fukushima A, Ukeba D, Iwasaki N, Sudo H. A Review: Methodologies to Promote the Differentiation of Mesenchymal Stem Cells for the Regeneration of Intervertebral Disc Cells Following Intervertebral Disc Degeneration. Cells 2023; 12:2161. [PMID: 37681893 PMCID: PMC10486900 DOI: 10.3390/cells12172161] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2023] [Revised: 08/24/2023] [Accepted: 08/26/2023] [Indexed: 09/09/2023] Open
Abstract
Intervertebral disc (IVD) degeneration (IDD), a highly prevalent pathological condition worldwide, is widely associated with back pain. Treatments available compensate for the impaired function of the degenerated IVD but typically have incomplete resolutions because of their adverse complications. Therefore, fundamental regenerative treatments need exploration. Mesenchymal stem cell (MSC) therapy has been recognized as a mainstream research objective by the World Health Organization and was consequently studied by various research groups. Implanted MSCs exert anti-inflammatory, anti-apoptotic, and anti-pyroptotic effects and promote extracellular component production, as well as differentiation into IVD cells themselves. Hence, the ultimate goal of MSC therapy is to recover IVD cells and consequently regenerate the extracellular matrix of degenerated IVDs. Notably, in addition to MSC implantation, healthy nucleus pulposus (NP) cells (NPCs) have been implanted to regenerate NP, which is currently undergoing clinical trials. NPC-derived exosomes have been investigated for their ability to differentiate MSCs from NPC-like phenotypes. A stable and economical source of IVD cells may include allogeneic MSCs from the cell bank for differentiation into IVD cells. Therefore, multiple alternative therapeutic options should be considered if a refined protocol for the differentiation of MSCs into IVD cells is established. In this study, we comprehensively reviewed the molecules, scaffolds, and environmental factors that facilitate the differentiation of MSCs into IVD cells for regenerative therapies for IDD.
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Affiliation(s)
- Takashi Ohnishi
- Department of Orthopedic Surgery, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo 060-8638, Japan; (T.O.); (K.H.); (A.F.); (N.I.)
| | - Kentaro Homan
- Department of Orthopedic Surgery, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo 060-8638, Japan; (T.O.); (K.H.); (A.F.); (N.I.)
| | - Akira Fukushima
- Department of Orthopedic Surgery, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo 060-8638, Japan; (T.O.); (K.H.); (A.F.); (N.I.)
| | - Daisuke Ukeba
- Department of Orthopedic Surgery, Hokkaido University Hospital, Sapporo 060-8648, Japan;
| | - Norimasa Iwasaki
- Department of Orthopedic Surgery, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo 060-8638, Japan; (T.O.); (K.H.); (A.F.); (N.I.)
| | - Hideki Sudo
- Department of Advanced Medicine for Spine and Spinal Cord Disorders, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo 060-8638, Japan
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6
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Mecwan M, Haghniaz R, Najafabadi AH, Mandal K, Jucaud V, John JV, Khademhosseini A. Thermoresponsive shear-thinning hydrogel (T-STH) hemostats for minimally invasive treatment of external hemorrhages. Biomater Sci 2023; 11:949-963. [PMID: 36537259 DOI: 10.1039/d2bm01559e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Hemorrhage is the leading cause of death following battlefield injuries. Although several hemostats are commercially available, they do not meet all the necessary requirements to stop bleeding in combat injuries. Here, we engineer thermoresponsive shear-thinning hydrogels (T-STH) composed of a thermoresponsive polymer, poly(N-isopropyl acrylamide) (p(NIPAM)), and hemostatic silicate nanodisks, LAPONITE®, as minimally invasive injectable hemostatic agents. Our T-STH is a physiologically stable hydrogel that can be easily injected through a syringe and needle and exhibits rapid mechanical recovery. Additionally, it demonstrates temperature-dependent blood coagulation owing to the phase transition of p(NIPAM). It decreases in vitro blood clotting times over 50% at physiological temperatures compared to room temperature. Furthermore, it significantly prevents blood loss in an ex vivo bleeding model at different blood flow rates (1 mL min-1 and 5 mL min-1) by forming a wound plug. More importantly, our T-STH is comparable to a commercially available hemostat, Floseal, in terms of blood loss and blood clotting time in an in vivo rat liver bleeding model. Furthermore, once the hemorrhage is stabilized, our T-STH can be easily removed using a cold saline wash without any rebleeding or leaving any residues. Taken together, our T-STH can be used as a first aid hemostat to treat external hemorrhages in emergency situations.
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Affiliation(s)
- Marvin Mecwan
- Terasaki Institute for Biomedical Innovation, Los Angeles, CA 90064, USA.
| | - Reihaneh Haghniaz
- Terasaki Institute for Biomedical Innovation, Los Angeles, CA 90064, USA.
| | | | - Kalpana Mandal
- Terasaki Institute for Biomedical Innovation, Los Angeles, CA 90064, USA.
| | - Vadim Jucaud
- Terasaki Institute for Biomedical Innovation, Los Angeles, CA 90064, USA.
| | - Johnson V John
- Terasaki Institute for Biomedical Innovation, Los Angeles, CA 90064, USA.
| | - Ali Khademhosseini
- Terasaki Institute for Biomedical Innovation, Los Angeles, CA 90064, USA.
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7
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Häkkinen S, Tanaka J, Garcia Maset R, Hall SCL, Huband S, Rho JY, Song Q, Perrier S. Polymerisation-Induced Self-Assembly of Graft Copolymers. Angew Chem Int Ed Engl 2022; 61:e202210518. [PMID: 36002384 PMCID: PMC9828155 DOI: 10.1002/anie.202210518] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Indexed: 01/12/2023]
Abstract
We report the polymerisation-induced self-assembly of poly(lauryl methacrylate)-graft-poly(benzyl methacrylate) copolymers during reversible addition-fragmentation chain transfer (RAFT) grafting from polymerisation in a backbone-selective solvent. Electron microscopy images suggest the phase separation of grafts to result in a network of spherical particles, due to the ability of the branched architecture to freeze chain entanglements and to bridge core domains. Small-angle X-ray scattering data suggest the architecture promotes the formation of multicore micelles, the core morphology of which transitions from spheres to worms, vesicles, and inverted micelles with increasing volume fraction of the grafts. A time-resolved SAXS study is presented to illustrate the formation of the inverted phase during a polymerisation. The grafted architecture gives access to unusual morphologies and provides exciting new handles for controlling the polymer structure and material properties.
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Affiliation(s)
- Satu Häkkinen
- Department of ChemistryUniversity of WarwickCoventryCV4 7ALUK
| | - Joji Tanaka
- Department of ChemistryUniversity of WarwickCoventryCV4 7ALUK,Department of ChemistryUniversity of North Carolina at Chapel HillChapel HillNC 27599-3290USA
| | - Ramón Garcia Maset
- Department of ChemistryUniversity of North Carolina at Chapel HillChapel HillNC 27599-3290USA
| | - Stephen C. L. Hall
- Department of ChemistryUniversity of WarwickCoventryCV4 7ALUK,ISIS Neutron and Muon SourceRutherford Appleton LaboratoryDidcotOX11 0QXUK
| | - Steven Huband
- Department of ChemistryUniversity of North Carolina at Chapel HillChapel HillNC 27599-3290USA
| | - Julia Y. Rho
- Department of ChemistryUniversity of North Carolina at Chapel HillChapel HillNC 27599-3290USA
| | - Qiao Song
- Department of ChemistryUniversity of North Carolina at Chapel HillChapel HillNC 27599-3290USA
| | - Sébastien Perrier
- Department of ChemistryUniversity of WarwickCoventryCV4 7ALUK,Warwick Medical SchoolUniversity of WarwickCoventryCV4 7ALUK
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8
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Hakkinen S, Tanaka J, Garcia Macet R, Hall S, Huband S, Rho J, Song Q, Perrier S. Polymerisation‐Induced Self‐Assembly of Graft Copolymers. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202210518] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
| | - Joji Tanaka
- University of Warwick Chemistry UNITED KINGDOM
| | | | | | | | - Julia Rho
- University of Warwick Chemistry UNITED KINGDOM
| | - Qiao Song
- University of Warwick Chemistry UNITED KINGDOM
| | - Sebastien Perrier
- University of Warwick Department of Chemistry Library Road CV4 7AL Coventry UNITED KINGDOM
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9
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Brotherton EE, Neal TJ, Kaldybekov DB, Smallridge MJ, Khutoryanskiy VV, Armes SP. Aldehyde-functional thermoresponsive diblock copolymer worm gels exhibit strong mucoadhesion. Chem Sci 2022; 13:6888-6898. [PMID: 35774174 PMCID: PMC9200053 DOI: 10.1039/d2sc02074b] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Accepted: 05/17/2022] [Indexed: 11/28/2022] Open
Abstract
A series of thermoresponsive diblock copolymer worm gels is prepared via reversible addition–fragmentation chain transfer (RAFT) aqueous dispersion polymerization of 2-hydroxypropyl methacrylate using a water-soluble methacrylic precursor bearing pendent cis-diol groups. Selective oxidation using an aqueous solution of sodium periodate affords the corresponding aldehyde-functional worm gels. The aldehyde groups are located within the steric stabilizer chains and the aldehyde content can be adjusted by varying the periodate/cis-diol molar ratio. These aldehyde-functional worm gels are evaluated in terms of their mucoadhesion performance with the aid of a fluorescence microscopy-based assay. Using porcine urinary bladder mucosa as a model substrate, we demonstrate that these worm gels offer a comparable degree of mucoadhesion to that afforded by chitosan, which is widely regarded to be a ‘gold standard’ positive control in this context. The optimum degree of aldehyde functionality is approximately 30%: lower degrees of functionalization lead to weaker mucoadhesion, whereas higher values compromise the desirable thermoresponsive behavior of these worm gels. Optimizing the aldehyde content of thermoresponsive diblock copolymer worm gels via periodate oxidation leads to mucoadhesion performance comparable to that of chitosan (a gold standard positive control) in a fluorescence assay using porcine mucosa.![]()
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Affiliation(s)
- Emma E Brotherton
- Dainton Building, Department of Chemistry, University of Sheffield Brook Hill Sheffield South Yorkshire S3 7HF UK
| | - Thomas J Neal
- Dainton Building, Department of Chemistry, University of Sheffield Brook Hill Sheffield South Yorkshire S3 7HF UK
| | - Daulet B Kaldybekov
- School of Pharmacy, University of Reading, Whiteknights PO Box 224, Reading Berkshire RG6 6DX UK .,Department of Chemistry and Chemical Technology, Al-Farabi Kazakh National University Almaty 050040 Kazakhstan
| | | | - Vitaliy V Khutoryanskiy
- School of Pharmacy, University of Reading, Whiteknights PO Box 224, Reading Berkshire RG6 6DX UK
| | - Steven P Armes
- Dainton Building, Department of Chemistry, University of Sheffield Brook Hill Sheffield South Yorkshire S3 7HF UK
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10
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Cumming J, Deane OJ, Armes SP. Reversible Addition-Fragmentation Chain Transfer Aqueous Dispersion Polymerization of 4-Hydroxybutyl Acrylate Produces Highly Thermoresponsive Diblock Copolymer Nano-Objects. Macromolecules 2022; 55:788-798. [PMID: 35431331 PMCID: PMC9007527 DOI: 10.1021/acs.macromol.1c02431] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Revised: 12/29/2021] [Indexed: 02/08/2023]
Abstract
The reversible addition-fragmentation chain transfer (RAFT) aqueous dispersion polymerization of 2-hydroxypropyl methacrylate (HPMA) using a poly(glycerol monomethacrylate) (PGMA) precursor is an important prototypical example of polymerization-induced self-assembly. 4-Hydroxybutyl acrylate (HBA) is a structural isomer of HPMA, but the former monomer exhibits appreciably higher aqueous solubility. For the two corresponding homopolymers, PHBA is more weakly hydrophobic than PHPMA. Moreover, PHBA has a significantly lower glass transition temperature (T g) so it exhibits much higher chain mobility than PHPMA at around ambient temperature. In view of these striking differences, we have examined the RAFT aqueous dispersion polymerization of HBA using a PGMA precursor with the aim of producing a series of PGMA57-300-PHBA100-1580 diblock copolymer nano-objects by systematic variation of the mean degree of polymerization of each block. A pseudo-phase diagram is constructed using transmission electron microscopy to assign the copolymer morphology after employing glutaraldehyde to cross-link the PHBA chains and hence prevent film formation during grid preparation. The thermoresponsive character of the as-synthesized linear nano-objects is explored using dynamic light scattering and temperature-dependent rheological measurements. Comparison with the analogous PGMA x -PHPMA y formulation is made where appropriate. In particular, we demonstrate that replacing the structure-directing PHPMA block with PHBA leads to significantly greater thermoresponsive behavior over a much wider range of diblock copolymer compositions. Given that PGMA-PHPMA worm gels can induce stasis in human stem cells (see Canton et al., ACS Central Science, 2016, 2, 65-74), our findings are likely to have implications for the design of next-generation PGMA-PHBA worm gels for cell biology applications.
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Affiliation(s)
- Juliana
M. Cumming
- Dainton Building, Department
of Chemistry, University of Sheffield, Brook Hill, Sheffield, South
Yorkshire S3 7HF, UK
| | - Oliver J. Deane
- Dainton Building, Department
of Chemistry, University of Sheffield, Brook Hill, Sheffield, South
Yorkshire S3 7HF, UK
| | - Steven P. Armes
- Dainton Building, Department
of Chemistry, University of Sheffield, Brook Hill, Sheffield, South
Yorkshire S3 7HF, UK
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11
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Deane OJ, Jennings J, Armes SP. Shape-shifting thermoreversible diblock copolymer nano-objects via RAFT aqueous dispersion polymerization of 4-hydroxybutyl acrylate. Chem Sci 2021; 12:13719-13729. [PMID: 34760156 PMCID: PMC8549797 DOI: 10.1039/d1sc05022b] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Accepted: 09/27/2021] [Indexed: 11/21/2022] Open
Abstract
2-Hydroxypropyl methacrylate (HPMA) is a useful model monomer for understanding aqueous dispersion polymerization. 4-Hydroxybutyl acrylate (HBA) is an isomer of HPMA: it has appreciably higher aqueous solubility so its homopolymer is more weakly hydrophobic. Moreover, PHBA possesses a significantly lower glass transition temperature than PHPMA, which ensures greater chain mobility. The reversible addition-fragmentation chain transfer (RAFT) aqueous dispersion polymerization of HBA using a poly(ethylene glycol) (PEG113) precursor at 30 °C produces PEG113-PHBA200-700 diblock copolymer nano-objects. Using glutaraldehyde to crosslink the PHBA chains allows TEM studies, which reveal the formation of spheres, worms or vesicles under appropriate conditions. Interestingly, the partially hydrated highly mobile PHBA block enabled linear PEG113-PHBA x spheres, worms or vesicles to be reconstituted from freeze-dried powders on addition of water at 20 °C. Moreover, variable temperature 1H NMR studies indicated that the apparent degree of hydration of the PHBA block increases from 5% to 80% on heating from 0 °C to 60 °C indicating uniform plasticization. In contrast, the PHPMA x chains within PEG113-PHPMA x nano-objects become dehydrated on raising the temperature: this qualitative difference is highly counter-intuitive given that PHBA and PHPMA are isomers. The greater (partial) hydration of the PHBA block at higher temperature drives the morphological evolution of PEG113-PHBA260 spheres to form worms or vesicles, as judged by oscillatory rheology, dynamic light scattering, small-angle X-ray scattering and TEM studies. Finally, a variable temperature phase diagram is constructed for 15% w/w aqueous dispersions of eight PEG113-PHBA200-700 diblock copolymers. Notably, PEG113-PHBA350 can switch reversibly from spheres to worms to vesicles to lamellae during a thermal cycle.
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Affiliation(s)
- Oliver J Deane
- Dainton Building, Department of Chemistry, University of Sheffield Brook Hill Sheffield South Yorkshire S3 7HF UK
| | - James Jennings
- Dainton Building, Department of Chemistry, University of Sheffield Brook Hill Sheffield South Yorkshire S3 7HF UK
| | - Steven P Armes
- Dainton Building, Department of Chemistry, University of Sheffield Brook Hill Sheffield South Yorkshire S3 7HF UK
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Derry MJ, Mykhaylyk OO, Armes SP. Shear-induced alignment of block copolymer worms in mineral oil. SOFT MATTER 2021; 17:8867-8876. [PMID: 34542137 DOI: 10.1039/d1sm01011e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Poly(stearyl methacrylate)-poly(benzyl methacrylate) [PSMA-PBzMA] diblock copolymer worms were synthesized directly in mineral oil via reversible addition-fragmentation chain transfer (RAFT) dispersion polymerization at 90 °C. Free-standing gels were obtained from this polymerization-induced self-assembly (PISA) formulation when targeting PSMA13-PBzMA65 dispersions at 5% w/w to 20% w/w copolymer concentration. Gel permeation chromatography (GPC) studies indicated that almost identical copolymer chains were obtained in all cases, while transmission electron microscopy (TEM) and small-angle X-ray scattering (SAXS) studies confirmed that highly anisotropic worms were formed with mean cross-sectional diameters of 11.9-13.1 nm. These worms undergo a thermoreversible worm-to-sphere transition on heating up to 150 °C. Rheological studies were conducted to characterize the shear rate- and concentration-dependent behaviour caused by this change in copolymer morphology, where the initial shear-thinning worm gels form spheres (i.e. a Newtonian fluid) on heating up to 150 °C. Complementary shear-induced polarized light imaging (SIPLI) experiments confirmed the formation of aligned linear worms under applied shear between 80 °C and 110 °C, with high-viscosity dispersions of branched worms being obtained at 20-60 °C and low-viscosity spheres being produced at 150 °C. This study informs the use of such block copolymer worms as rheology modifiers for non-polar oils, which is of potential interest for the automotive industry.
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Affiliation(s)
- Matthew J Derry
- Department of Chemistry, University of Sheffield, Dainton Building, Brook Hill, Sheffield, S3 7HF, UK.
| | - Oleksandr O Mykhaylyk
- Department of Chemistry, University of Sheffield, Dainton Building, Brook Hill, Sheffield, S3 7HF, UK.
| | - Steven P Armes
- Department of Chemistry, University of Sheffield, Dainton Building, Brook Hill, Sheffield, S3 7HF, UK.
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13
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Georgiou P, Marton HL, Baker AN, Congdon TR, Whale TF, Gibson MI. Polymer Self-Assembly Induced Enhancement of Ice Recrystallization Inhibition. J Am Chem Soc 2021; 143:7449-7461. [PMID: 33944551 PMCID: PMC8154521 DOI: 10.1021/jacs.1c01963] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Indexed: 02/07/2023]
Abstract
Ice binding proteins modulate ice nucleation/growth and have huge (bio)technological potential. There are few synthetic materials that reproduce their function, and rational design is challenging due to the outstanding questions about the mechanisms of ice binding, including whether ice binding is essential to reproduce all their macroscopic properties. Here we report that nanoparticles obtained by polymerization-induced self-assembly (PISA) inhibit ice recrystallization (IRI) despite their constituent polymers having no apparent activity. Poly(ethylene glycol), poly(dimethylacrylamide), and poly(vinylpyrrolidone) coronas were all IRI-active when assembled into nanoparticles. Different core-forming blocks were also screened, revealing the core chemistry had no effect. These observations show ice binding domains are not essential for macroscopic IRI activity and suggest that the size, and crowding, of polymers may increase the IRI activity of "non-active" polymers. It was also discovered that poly(vinylpyrrolidone) particles had ice crystal shaping activity, indicating this polymer can engage ice crystal surfaces, even though on its own it does not show any appreciable ice recrystallization inhibition. Larger (vesicle) nanoparticles are shown to have higher ice recrystallization inhibition activity compared to smaller (sphere) particles, whereas ice nucleation activity was not found for any material. This shows that assembly into larger structures can increase IRI activity and that increasing the "size" of an IRI does not always lead to ice nucleation. This nanoparticle approach offers a platform toward ice-controlling soft materials and insight into how IRI activity scales with molecular size of additives.
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Affiliation(s)
- Panagiotis
G. Georgiou
- Department
of Chemistry, University of Warwick, Gibbet Hill Road, CV4 7AL Coventry, U.K.
| | - Huba L. Marton
- Department
of Chemistry, University of Warwick, Gibbet Hill Road, CV4 7AL Coventry, U.K.
| | - Alexander N. Baker
- Department
of Chemistry, University of Warwick, Gibbet Hill Road, CV4 7AL Coventry, U.K.
| | - Thomas R. Congdon
- Department
of Chemistry, University of Warwick, Gibbet Hill Road, CV4 7AL Coventry, U.K.
| | - Thomas F. Whale
- Department
of Chemistry, University of Warwick, Gibbet Hill Road, CV4 7AL Coventry, U.K.
| | - Matthew I. Gibson
- Department
of Chemistry, University of Warwick, Gibbet Hill Road, CV4 7AL Coventry, U.K.
- Warwick
Medical School, University of Warwick, Gibbet Hill Road, CV4 7AL Coventry, U.K.
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