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


  • This study was supported in part by Monbukagakusho, Japan (the 21st Century COE Program for Frontiers in Fundamental Chemistry to E.N., grant-in-aid for Scientific Research, Young Scientists (A) to H.I.). We thank Dr. K. Suenaga and Dr. Z. Liu for TEM analysis, Prof. Y. Umezawa and Dr. M. Sato for advice on confocal microscopy, and Dr. J. Miyawaki for Raman spectroscopic measurements. N.S. thanks the Knut och Alice Wallenbergs Stiftelse (Stockholm, Sweden) for a postdoctoral fellowship.


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The risk assessment of carbon materials, an important topic in nanomaterials research, has been hampered by the lack of characterizable samples. Transition-metal-free carbon nanohorn aggregates have been prepared that are covalently bonded aggregates of single-walled nanotubes. They were functionalized to give water-soluble derivatives (see picture), which were incubated with cells in cytotoxicity assessments.