Preparation, Purification, Characterization, and Cytotoxicity Assessment of Water‐Soluble, Transition‐Metal‐Free Carbon Nanotube Aggregates

Isobe, Hiroyuki; Tanaka, Terumichi; Maeda, Ryo; Noiri, Eisei; Solin, Niclas; Yudasaka, Masako; Iijima, Sumio; Nakamura, Eiichi

doi:10.1002/anie.200601718

Cited by 151 publications

(103 citation statements)

References 33 publications

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“…The UV-vis-NIR optical absorption spectrum of PBS dispersions of BSA-CNH peaked at 260 nm (Fig. 1B), characteristic of the absorption of tubular graphite and BSA molecules (27,28,44). The BSA-CNH complexes were ∼100-200 nm in diameter as estimated by atomic force microscopy and dynamic light scattering analyses (SI Appendix, Fig.…”

Section: Resultsmentioning

confidence: 93%

“…Potential problems exist with CNT biocompatibility, however, including impurities in the metal catalysts used in CNT synthesis (39,40). Conversely, CNHs are produced without metal catalysts and have relatively low toxicity, as shown in both in vitro and in vivo experiments (41)(42)(43)(44)(45). Thus, CNHs appear to be more amenable than CNTs for use in various biomedical and biotechnological applications.…”

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confidence: 99%

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Photothermic regulation of gene expression triggered by laser-induced carbon nanohorns

Miyako

Deguchi

Nakajima

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

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The development of optical methods to control cellular functions is important for various biological applications. In particular, heat shock promoter-mediated gene expression systems by laser light are attractive targets for controlling cellular functions. However, previous approaches have considerable technical limitations related to their use of UV, short-wavelength visible (vis), and infrared (IR) laser light, which have poor penetration into biological tissue. Biological tissue is relatively transparent to light inside the diagnostic window at wavelengths of 650–1,100 nm. Here we present a unique optical biotechnological method using carbon nanohorn (CNH) that transforms energy from diagnostic window laser light to heat to control the expression of various genes. We report that with this method, laser irradiation within the diagnostic window resulted in effective heat generation and thus caused heat shock promoter-mediated gene expression. This study provides an important step forward in the development of light-manipulated gene expression technologies.

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Section: Resultsmentioning

confidence: 93%

mentioning

confidence: 99%

Photothermic regulation of gene expression triggered by laser-induced carbon nanohorns

Miyako

Deguchi

Nakajima

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

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“…Clearly, fullerenes have a dual nature, exhibiting both beneficial effects and malign toxicities. Standardization for the material-evaluation of fullerene is therefore required, as we recently suggested (46).…”

Section: Discussionmentioning

confidence: 99%

A Water-Soluble Fullerene Vesicle Alleviates Angiotensin II-Induced Oxidative Stress in Human Umbilical Venous Endothelial Cells

et al. 2008

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“…19 However, the presence of metal impurities can cause confusion about the biocompatibility, toxicity and health risks of CNTs. 3,20 For example, intracellular reactive oxygen species (ROS) were reported to be dependent on contaminants 21 ; however, another report showed that neither purified nor non-purified SWCNTs containing significant amounts of iron were able to generate the intracellular production of superoxide radicals or nitric oxide in RAW 264.7 macrophages. 22 Ultrafine, transition-metal particles pose documented health risks upon inhalation, but their contributions to the toxicity of CNTs remain unclear due to their apparent encapsulation and immobilization by carbon shells.…”

Section: Introductionmentioning

confidence: 99%

The contributions of metal impurities and tube structure to the toxicity of carbon nanotube materials

et al. 2012

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Due to the existence of considerable quantities of metallic and carbonaceous impurities, the key factor and mechanism for the reported toxicity of carbon nanotubes (CNTs) are unclear. Here, we first quantify the contribution of metal residues and fiber structure to the toxicity of CNTs. Significant quantities of metal particles could be mobilized from CNTs into surrounding fluids, depending on the properties and constituents of the biological microenvironment, as well as the properties of metal particles. Furthermore, electron spin resonance measurements confirm that hydroxyl radicals can be generated by both CNTs containing metal impurities and acid-leachable metals from CNTs. Several biomolecules facilitate the generation of free radicals, which might be due to the participation of these biomolecules in redox cycling influenced by pH. Among several major metal residues, Fe has a critical role in generating hydroxyl radicals, reducing cell viability and promoting intracellular reactive oxidative species. Cell viability is highly dependent on the amount of metal residues and iron in particular, but not tube structure, while the negative effect of CNTs themselves on cell viability is very limited in a certain concentration range below 80 lg ml À1 . It is crucial to systematically understand how these exogenous and endogenous factors influence the toxicity of CNTs to avoid their undesirable toxicity. Keywords: biological microenvironments; carbon nanotube; metal impurities; reactive oxygen species; toxicity INTRODUCTION Engineered nanomaterials possess novel properties and have been used worldwide in numerous consumer products, for example, food, clothes, pharmaceuticals and cleaning products. Estimates suggest that by 2015 nanotechnology will have a trillion-plus dollar global economic impact. 1 Therefore, ensuring the safety of nanomaterials is of great importance to the tremendous commercial applications of nanotechnology. Safety evaluation of nanomaterials should consider their behaviors in various aspects, including their interaction with proteins, DNA, lipids, membranes, organelles, cells, tissues, biological fluids and even the dissolution of metal constituents. [2][3][4] Carbon nanotubes (CNTs) have attracted great interest from both scientists and the industry because their high aspect ratios, strength and remarkable physical properties make them a unique material with a wide range of promising applications. Many applications of CNTs in biomedicine have been proposed, including nanoelectronics, 4 biosensors, 5 biomolecular recognition devices and molecular transporters, 6 artificial water channels, 7 cancer therapy 8,9 and photoacoustic molecular imaging. 10 Because transitional metals are often used as catalysts during CNT synthesis, 11 it is unavoidable that as-received CNTs are contaminated by catalyst residues. 12 The catalyst precursor (such as iron carbonyl) decomposes, and nanometer-sized metal particles form from the decomposition products. Therefore,

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Preparation, Purification, Characterization, and Cytotoxicity Assessment of Water‐Soluble, Transition‐Metal‐Free Carbon Nanotube Aggregates

Cited by 151 publications

References 33 publications

Photothermic regulation of gene expression triggered by laser-induced carbon nanohorns

Photothermic regulation of gene expression triggered by laser-induced carbon nanohorns

A Water-Soluble Fullerene Vesicle Alleviates Angiotensin II-Induced Oxidative Stress in Human Umbilical Venous Endothelial Cells

The contributions of metal impurities and tube structure to the toxicity of carbon nanotube materials

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