Chen, S, Hu, S, Smith, EF et al. (8 more authors) (2014) Aqueous cationic, anionic and non-ionic multi-walled carbon nanotubes, functionalised with minimal framework damage, for biomedical application. Biomaterials, 35 (17). pp. 4729-4738. ISSN 0142-9612
Abstract
The use of a thermochemical grafting approach provides a versatile means to functionalise as-synthesised, bulk multi-walled carbon nanotubes (MWNTs) without altering their inherent structure. The associated retention of properties is desirable for a wide range of commercial applications, including for drug delivery and medical purposes; it is also pertinent to studies of intrinsic toxicology. A systematic series of water-compatible MWNTs, with diameter around 12 nm have been prepared, to provide structurally-equivalent samples predominantly stabilised by anionic, cationic, or non-ionic groups. The surface charge of MWNTs was controlled by varying the grafting reagents and subsequent post-functionalisation modifications. The degree of grafting was established by thermal analysis (TGA). High resolution transmission electron microscope (HRTEM) and Raman measurements confirmed that the structural framework of the MWNTs was unaffected by the thermochemical treatment, in contrast to a conventional acid-oxidised control which was severely damaged. The effectiveness of the surface modification was demonstrated by significantly improved solubility and stability in both water and cell culture medium, and further quantified by zeta-potential analysis. The grafted MWNTs exhibited relatively low bioreactivity on transformed human alveolar epithelial type 1-like cells (TT1) following 24 h exposure as demonstrated by 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) and lactate dehydrogenase release (LDH) assays. The exposure of TT1 cells to MWNTs suppressed the release of the inflammatory mediators, interleukin 6 (IL-6) and interleukin 8 (IL-8). TEM cell uptake studies indicated efficient cellular entry of MWNTs into TT1 cells, via a range of mechanisms. Cationic MWNTs showed a more substantial interaction with TT1 cell membranes than anionic MWNTs, demonstrating a surface charge effect on cell uptake.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2014 Elsevier Ltd. This is an author produced version of a paper published in Biomaterials. Uploaded in accordance with the publisher's self-archiving policy. |
Keywords: | Multiwalled carbon nanotubes; Thermal chemical functionalisation; Integrity structure; Surface charge; Cytotoxicity; Cell uptake |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Chemistry (Leeds) > Inorganic Chemistry (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 28 Feb 2018 09:41 |
Last Modified: | 05 Mar 2018 05:18 |
Status: | Published |
Publisher: | Elsevier |
Identification Number: | 10.1016/j.biomaterials.2014.02.002 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:121579 |