Water-proton relaxivity of hyperbranched polymers carrying TEMPO radicals.

Authors :: Hayashi H
Karasawa S
Tanaka A
Odoi K
Chikama K
Kuribayashi H
Koga N
Source :: Magnetic resonance in chemistry : MRC [Magn Reson Chem] 2009 Mar; Vol. 47 (3), pp. 201-4.
Publication Year :: 2009
Abstract: High water-soluble hyperbranched poly(styrene) (HPS) polymers carrying stable 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) radicals, HPS-N-TEMPO, HPS-Im-TEMPO, and HPS-Im-(TEMPO)(2), were prepared in ca. 60% introducing yield. HPS-N-TEMPO and HPS-Im-TEMPO were determined to be nearly spherical shapes of the diameter of 2.4 +/- 0.6 and 2.2 +/- 0.6 nm, respectively, by transmission electron microscope (TEM) images. The values of water-proton relaxivity, r(1), at 25 MHz, 0.59 T, and 25 degrees C were 6.0, 5.2, and 14 mM(-1) sec(-1) for HPS-N-TEMPO, HPS-Im-TEMPO, and HPS-Im-(TEMPO)(2), respectively. The spin-lattice relaxation time (T(1))-weighted images in phantom were also observed.<br /> (2009 John Wiley & Sons, Ltd.)