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Very‐low‐frequency electron paramagnetic resonance (EPR) imaging of nitroxide‐loaded cells
Author(s) -
Kao Joseph P.Y.,
Barth Eugene D.,
Burks Scott R.,
Smithback Philip,
Mailer Colin,
Ahn KangHyun,
Halpern Howard J.,
Rosen Gerald M.
Publication year - 2007
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.21388
Subject(s) - nitroxide mediated radical polymerization , electron paramagnetic resonance , in vivo , nuclear magnetic resonance , imaging phantom , chemistry , magnetic resonance imaging , spin probe , paramagnetism , intracellular , biophysics , materials science , nuclear medicine , biochemistry , physics , biology , medicine , radiology , microbiology and biotechnology , radical polymerization , quantum mechanics , copolymer , polymer
Recent advances in electron paramagnetic resonance (EPR) imaging have made it possible to image, in real time in vivo, cells that have been labeled with nitroxide spin probes. We previously reported that cells can be loaded to high (millimolar) intracellular concentrations with (2,2,5,5‐tetramethylpyrrolidin‐1‐oxyl‐3‐ylmethyl)amine‐ N , N ‐diacetic acid by incubation with the corresponding acetoxymethyl (AM) ester. Furthermore, the intracellular lifetime ( t 1/ e ) of this nitroxide is 114 min—sufficiently long to permit in vivo imaging studies. In the present study, at a gradient of ∼50 mT/m, we acquire and compare EPR images of a three‐tube phantom, filled with either a 200‐μM solution of the nitroxide, or a suspension of cells preincubated with the nitroxide AM ester. In both cases, 3‐mm resolution images can be acquired with excellent signal‐to‐noise ratios (SNRs). These findings indicate that cells well‐loaded with nitroxide are readily imageable by EPR imaging, and that in vivo tracking studies utilizing such cells should be feasible. Magn Reson Med 58:850–854, 2007. © 2007 Wiley‐Liss, Inc.