Water-proton relaxivity of hyperbranched polymers carrying TEMPO radicals.
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.
Hayashi
Hiroyuki
H
Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582 Japan.
Karasawa
Satoru
S
Tanaka
Akihiro
A
Odoi
Keisuke
K
Chikama
Katsumi
K
Kuribayashi
Hideto
H
Koga
Noboru
N
D046529:Microscopy, Electron, Transmission; D015394:Molecular Structure; D010880:Piperidines / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry*; D011522:Protons; D014867:Water / Q000737:chemistry*
C528764:2,2,6,6-tetramethyl-1-piperidine; D010880:Piperidines; D011108:Polymers; D011522:Protons; D014867:Water