Single-Walled Carbon Nanotube Materials as T2-Weighted MRI Contrast Agents

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 ultra-short 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 (<100 nm), negligible metal content (<1% Fe (wt %)), and superior T2 relaxation efficiency (T2 = 31.7 ms per mg SWNT at 3 T and 37 °C) are the most promising candidates for advanced applications such as molecular and cellular imaging using MRI.