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Chen T, Lau KSK, Hong SH, Shi HTH, Iwasa SN, Chen JXM, Li T, Morrison T, Kalia SK, Popovic MR, Morshead CM, Naguib HE. Cryogel-based neurostimulation electrodes to activate endogenous neural precursor cells. Acta Biomater 2023; 171:392-405. [PMID: 37683963 DOI: 10.1016/j.actbio.2023.08.056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Revised: 08/24/2023] [Accepted: 08/29/2023] [Indexed: 09/10/2023]
Abstract
The delivery of electrical pulses to the brain via penetrating electrodes, known as brain stimulation, has been recognized as an effective clinical approach for treating neurological disorders. Resident brain neural precursor cells (NPCs) are electrosensitive cells that respond to electrical stimulation by expanding in number, migrating and differentiating which are important characteristics that support neural repair. Here, we report the design of a conductive cryogel brain stimulation electrode specifically developed for NPC activation. The cryogel electrode has a modulus switching mechanism permitting facile penetration and reducing the mechanical mismatch between brain tissue and the penetrating electrode. The cryogel demonstrated good in vivo biocompatibility and reduced the interfacial impedance to deliver the stimulating electric field with lower voltage under charge-balanced current controlled stimulation. An ex vivo assay reveals that electrical stimulation using the cryogel electrodes results in significant expansion in the size of NPC pool. Hence, the cryogel electrodes have the potential to be used for NPC activation to support endogenous neural repair. STATEMENT OF SIGNIFICANCE: The objective of this study is to develop a cryogel-based stimulation electrode as an alternative to traditional electrode materials to be used in regenerative medicine applications for enhancing neural regeneration in brain. The electrode offers benefits such as adaptive modulus for implantation, high charge storage and injection capacities, and modulus matching with brain tissue, allowing for stable delivery of electric field for long-term neuromodulation. The electrochemical properties of cryogel electrodes were characterized in living tissue with an ex vivo set-up, providing a deeper understanding of stimulation capacity in brain environments. The cryogel electrode is biocompatible and enables low voltage, current-controlled stimulation for effective activation of endogenous neural precursor cells, revealing their potential utility in neural stem cell-mediated brain repair.
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Affiliation(s)
- Tianhao Chen
- Institute of Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada
| | - Kylie Sin Ki Lau
- Institute of Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada
| | - Sung Hwa Hong
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario, Canada
| | - Hao Tian Harvey Shi
- Department of Mechanical and Materials Engineering, Western University, London, Ontario, Canada
| | - Stephanie N Iwasa
- The KITE Research Institute, Toronto Rehabilitation Institute, University Health Network, Toronto, Ontario, Canada; CRANIA, University Health Network and University of Toronto, Toronto, Ontario, Canada
| | - Jia Xi Mary Chen
- Department of Materials Science and Engineering, University of Toronto, Toronto, Ontario, Canada
| | - Terek Li
- Department of Materials Science and Engineering, University of Toronto, Toronto, Ontario, Canada
| | - Taylor Morrison
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, Ontario, Canada
| | - Suneil K Kalia
- The KITE Research Institute, Toronto Rehabilitation Institute, University Health Network, Toronto, Ontario, Canada; CRANIA, University Health Network and University of Toronto, Toronto, Ontario, Canada; Department of Neurosurgery, University Health Network, University of Toronto, Toronto, Ontario, Canada; Krembil Research Institute, Toronto, Ontario, Canada; Department of Surgery, University of Toronto, Toronto, Ontario, Canada
| | - Milos R Popovic
- Institute of Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada; The KITE Research Institute, Toronto Rehabilitation Institute, University Health Network, Toronto, Ontario, Canada; CRANIA, University Health Network and University of Toronto, Toronto, Ontario, Canada
| | - Cindi M Morshead
- Institute of Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada; The KITE Research Institute, Toronto Rehabilitation Institute, University Health Network, Toronto, Ontario, Canada; CRANIA, University Health Network and University of Toronto, Toronto, Ontario, Canada; Department of Surgery, University of Toronto, Toronto, Ontario, Canada.
| | - Hani E Naguib
- Institute of Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada; Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario, Canada; Department of Materials Science and Engineering, University of Toronto, Toronto, Ontario, Canada; Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, Ontario, Canada.
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Arambula-Maldonado R, Liu Y, Xing M, Mequanint K. Bioactive and electrically conductive GelMA-BG-MWCNT nanocomposite hydrogel bone biomaterials. BIOMATERIALS ADVANCES 2023; 154:213616. [PMID: 37708668 DOI: 10.1016/j.bioadv.2023.213616] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Revised: 08/17/2023] [Accepted: 09/01/2023] [Indexed: 09/16/2023]
Abstract
Natural bone is a complex organic-inorganic composite tissue that possesses endogenous electrically conductive properties in response to mechanical forces. Mimicking these unique properties collectively in a single synthetic biomaterial has so far remained a formidable task. In this study, we report a synthesis strategy that comprised gelatin methacryloyl (GelMA), sol-gel derived tertiary bioactive glass (BG), and uniformly dispersed multiwall carbon nanotubes (MWCNTs) to create nanocomposite hydrogels that mimic the organic-inorganic composition of bone. Using this strategy, biomaterials that are electrically conductive and possess electro-mechanical properties similar to endogenous bone were prepared without affecting their biocompatibility. Nanocomposite hydrogel biomaterials were biodegradable and promoted biomineralization, and supported multipotent mesenchymal progenitor cell (10T1/2) cell interactions and differentiation into an osteogenic lineage. To the best of our knowledge, this work presents the first study to functionally characterize suitable electro-mechanical responses in nanocomposite hydrogels, a key process that occurs in the natural bone to drive its repair and regeneration. Overall, the results demonstrated GelMA-BG-MWCNT nanocomposite hydrogels have the potential to become promising bioactive biomaterials for use in bone repair and regeneration.
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Affiliation(s)
- Rebeca Arambula-Maldonado
- School of Biomedical Engineering, University of Western Ontario, 1151 Richmond Street, London N6A 5B9, Canada
| | - Yuqing Liu
- Department of Mechanical Engineering, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Malcolm Xing
- Department of Mechanical Engineering, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Kibret Mequanint
- School of Biomedical Engineering, University of Western Ontario, 1151 Richmond Street, London N6A 5B9, Canada; Department of Chemical and Biochemical Engineering, University of Western Ontario, 1151 Richmond Street, London N6A 5B9, Canada.
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Borges MHR, Nagay BE, Costa RC, Souza JGS, Mathew MT, Barão VAR. Recent advances of polypyrrole conducting polymer film for biomedical application: Toward a viable platform for cell-microbial interactions. Adv Colloid Interface Sci 2023; 314:102860. [PMID: 36931199 DOI: 10.1016/j.cis.2023.102860] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Revised: 02/04/2023] [Accepted: 02/13/2023] [Indexed: 02/18/2023]
Abstract
Polypyrrole (PPy) is one of the most studied conductive polymers due to its electrical conductivity and biological properties, which drive the possibility of numerous applications in the biomedical area. The physical-chemical features of PPy allow the manufacture of biocompatible devices, enhancing cell adhesion and proliferation. Furthermore, owing to the electrostatic interactions between the negatively charged bacterial cell wall and the positive charges in the polymer structure, PPy films can perform an effective antimicrobial activity. PPy is also frequently associated with biocompatible agents and antimicrobial compounds to improve the biological response. Thus, this comprehensive review appraised the available evidence regarding the PPy-based films deposited on metallic implanted devices for biomedical applications. We focus on understanding key concepts that could influence PPy attributes regarding antimicrobial effect and cell behavior under in vitro and in vivo settings. Furthermore, we unravel the several agents incorporated into the PPy film and strategies to improve its functionality. Our findings suggest that incorporating other elements into the PPy films, such as antimicrobial agents, biomolecules, and other biocompatible polymers, may improve the biological responses. Overall, the basic properties of PPy, when combined with other composites, electrostimulation techniques, or surface treatment methods, offer great potential in biocompatibility and/or antimicrobial activities. However, challenges in synthesis standardization and potential limitations such as low adhesion and mechanical strength of the film must be overcome to improve and broaden the application of PPy film in biomedical devices.
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Affiliation(s)
- Maria H R Borges
- Department of Prosthodontics and Periodontology, Piracicaba Dental School, University of Campinas (UNICAMP), Piracicaba, São Paulo 13414-903, Brazil
| | - Bruna E Nagay
- Department of Prosthodontics and Periodontology, Piracicaba Dental School, University of Campinas (UNICAMP), Piracicaba, São Paulo 13414-903, Brazil
| | - Raphael C Costa
- Department of Prosthodontics and Periodontology, Piracicaba Dental School, University of Campinas (UNICAMP), Piracicaba, São Paulo 13414-903, Brazil
| | - João Gabriel S Souza
- Dental Research Division, Guarulhos University (UNG), Guarulhos, Sāo Paulo 07023-070, Brazil; Dental Science School (Faculdade de Ciências Odontológicas - FCO), Montes Claros, Minas Gerais 39401-303, Brazil
| | - Mathew T Mathew
- Department of Biomedical Sciences, University of Illinois, College of Medicine, Rockford, IL 61107, USA
| | - Valentim A R Barão
- Department of Prosthodontics and Periodontology, Piracicaba Dental School, University of Campinas (UNICAMP), Piracicaba, São Paulo 13414-903, Brazil.
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