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Non-covalent polymer wrapping of carbon nanotubes and the role of wrapped polymers as functional dispersants

View Article: PubMed Central - PubMed

ABSTRACT

Carbon nanotubes (CNTs) have been recognized as a promising material in a wide range of applications from biotechnology to energy-related devices. However, the poor solubility in aqueous and organic solvents hindered the applications of CNTs. As studies have progressed, the methodology for CNT dispersion was established. In this methodology, the key issue is to covalently or non-covalently functionalize the surfaces of the CNTs with a dispersant. Among the various types of dispersions, polymer wrapping through non-covalent interactions is attractive in terms of the stability and homogeneity of the functionalization. Recently, by taking advantage of their stability, the wrapped-polymers have been utilized to support and/or reinforce the unique functionality of the CNTs, leading to the development of high-performance devices. In this review, various polymer wrapping approaches, together with the applications of the polymer-wrapped CNTs, are summarized.

No MeSH data available.


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(a) A schematic model of DNA wrapped on SWCNTs. Color coding: orange, thymine; green, adenine; yellow ribbons, backbones. (b) Size exclusion chromatograms of SWCNTs dispersed by dsDNA (left) and the fraction re-injected after 1 month of the separation (right). The chromatograms were measured at 260 nm [55]. Part (a) reprinted by permission from Macmillan Publishers Ltd: X Tu et al 2009 Nature460 250, copyright 2009.
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Figure 17: (a) A schematic model of DNA wrapped on SWCNTs. Color coding: orange, thymine; green, adenine; yellow ribbons, backbones. (b) Size exclusion chromatograms of SWCNTs dispersed by dsDNA (left) and the fraction re-injected after 1 month of the separation (right). The chromatograms were measured at 260 nm [55]. Part (a) reprinted by permission from Macmillan Publishers Ltd: X Tu et al 2009 Nature460 250, copyright 2009.

Mentions: Individual wrapping of SWCNTs using double-strand DNA (dsDNA) and single-strand DNA (ssDNA) in an aqueous system was reported by our group [204] and Zheng et al [205], respectively. In these cases, the aromatic nucleic-acid base in DNA are also regarded as the pendant moiety used for the wrapping of CNTs [206–209] in which the stacking of the nucleic-acid base on the SWCNT surfaces leaving highly charged phosphate backbones exposed to water has been proposed both experimentally [206–208, 210] and theoretically (figure 17(a)) [209, 211]. As a matter of fact, dissolution of the CNTs is highly sequence-dependent, and poly-d(T) and d(GT)10-45 provides the highest concentration of individual SWCNT aqueous solutions [205, 212]. It was reported that the dispersion efficiency is so high that it exhibits a lyotropic LC phase in the high concentration region [213]. The thermodynamic stability of the DNA wrapping on the CNTs was proved by our group using the gel permeation chromatography (GPC) technique. After removing the unbound DNA in a solution by the GPC technique, no peak attributed to the free DNA was detected even after 1 month, obviously indicating the absence of the detachment of the DNA from the CNT surfaces (figure 17(b)) [55]. Due to the unique combination between biological materials and nano-carbon materials, together with the stable wrapping, a wide range of studies have been carried out for the DNA-wrapped CNTs, such as the conformation transition monitoring of DNA [214], redox sensing of glucose and hydrogen peroxide [215], hybridization detection between ssDNA and their complimentary DNA [56] and uptake estimation of DNA/SWCNTs into a cell [216, 217].


Non-covalent polymer wrapping of carbon nanotubes and the role of wrapped polymers as functional dispersants
(a) A schematic model of DNA wrapped on SWCNTs. Color coding: orange, thymine; green, adenine; yellow ribbons, backbones. (b) Size exclusion chromatograms of SWCNTs dispersed by dsDNA (left) and the fraction re-injected after 1 month of the separation (right). The chromatograms were measured at 260 nm [55]. Part (a) reprinted by permission from Macmillan Publishers Ltd: X Tu et al 2009 Nature460 250, copyright 2009.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
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getmorefigures.php?uid=PMC5036478&req=5

Figure 17: (a) A schematic model of DNA wrapped on SWCNTs. Color coding: orange, thymine; green, adenine; yellow ribbons, backbones. (b) Size exclusion chromatograms of SWCNTs dispersed by dsDNA (left) and the fraction re-injected after 1 month of the separation (right). The chromatograms were measured at 260 nm [55]. Part (a) reprinted by permission from Macmillan Publishers Ltd: X Tu et al 2009 Nature460 250, copyright 2009.
Mentions: Individual wrapping of SWCNTs using double-strand DNA (dsDNA) and single-strand DNA (ssDNA) in an aqueous system was reported by our group [204] and Zheng et al [205], respectively. In these cases, the aromatic nucleic-acid base in DNA are also regarded as the pendant moiety used for the wrapping of CNTs [206–209] in which the stacking of the nucleic-acid base on the SWCNT surfaces leaving highly charged phosphate backbones exposed to water has been proposed both experimentally [206–208, 210] and theoretically (figure 17(a)) [209, 211]. As a matter of fact, dissolution of the CNTs is highly sequence-dependent, and poly-d(T) and d(GT)10-45 provides the highest concentration of individual SWCNT aqueous solutions [205, 212]. It was reported that the dispersion efficiency is so high that it exhibits a lyotropic LC phase in the high concentration region [213]. The thermodynamic stability of the DNA wrapping on the CNTs was proved by our group using the gel permeation chromatography (GPC) technique. After removing the unbound DNA in a solution by the GPC technique, no peak attributed to the free DNA was detected even after 1 month, obviously indicating the absence of the detachment of the DNA from the CNT surfaces (figure 17(b)) [55]. Due to the unique combination between biological materials and nano-carbon materials, together with the stable wrapping, a wide range of studies have been carried out for the DNA-wrapped CNTs, such as the conformation transition monitoring of DNA [214], redox sensing of glucose and hydrogen peroxide [215], hybridization detection between ssDNA and their complimentary DNA [56] and uptake estimation of DNA/SWCNTs into a cell [216, 217].

View Article: PubMed Central - PubMed

ABSTRACT

Carbon nanotubes (CNTs) have been recognized as a promising material in a wide range of applications from biotechnology to energy-related devices. However, the poor solubility in aqueous and organic solvents hindered the applications of CNTs. As studies have progressed, the methodology for CNT dispersion was established. In this methodology, the key issue is to covalently or non-covalently functionalize the surfaces of the CNTs with a dispersant. Among the various types of dispersions, polymer wrapping through non-covalent interactions is attractive in terms of the stability and homogeneity of the functionalization. Recently, by taking advantage of their stability, the wrapped-polymers have been utilized to support and/or reinforce the unique functionality of the CNTs, leading to the development of high-performance devices. In this review, various polymer wrapping approaches, together with the applications of the polymer-wrapped CNTs, are summarized.

No MeSH data available.


Related in: MedlinePlus