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2009, 113, 19369–19372 Published on Web 10/20/2009
Single-Walled Carbon Nanotube Materials as T2-Weighted MRI Contrast Agents Jeyarama S. Ananta,† Michael L. Matson,† Annie M. Tang,‡ Trinanjana Mandal,† Stephen Lin,‡ Kelvin Wong,‡ Stephen T. Wong,‡ and Lon J. Wilson*,† Department of Chemistry, Smalley Institute for Nanoscale Science and Technology, Center for Biological and EnVironmental Nanotechnology, Rice UniVersity, Houston, Texas 77251-1892, and Center for Biotechnology and Informatics, The Methodist Hospital Research Institute and Department of Radiology, The Methodist Hospital, Weill Cornell Medical College, Houston, Texas 77030 ReceiVed: August 14, 2009; ReVised Manuscript ReceiVed: September 25, 2009
With their unique nanoscalar properties, single-walled carbon nanotube (SWNT) materials are widely studied for various biological applications. Herein, we report the efficiency of full-length HiPco SWNTs and ultrashort SWNTs (US-tubes) as T2-weighted MRI contrast agents. Analysis has concluded that the superparamagnetic SWNT materials (especially US-tubes) are a new class of high-efficacy contrast agents having performance contributions from both the iron catalyst nanoparticles (originating from the synthesis of SWNT materials) and the carbon SWNT material itself. The superparamagnetic US-tubes with their short length ( 5) and US-tubes (r2/r1 > 20) are effective as a T2-weighted contrast agents, but the US-tubes should be much more effective for specialized applications such as imaging biological processes at the molecular level. In fact, their superior r2 efficiency and exceptionally large r2/r1 ratio, along with their shorter length (
