Compatibility of superparamagnetic iron oxide nanoparticle labeling for 1 H MRI cell tracking with 31 P MRS for bioenergetic measurements

Labeling of cells with superparamagnetic iron oxide nanoparticles permits cell tracking by 1 H MRI while 31 P MRS allows non‐invasive evaluation of cellular bioenergetics. We evaluated the compatibility of these two techniques by obtaining 31 P NMR spectra of iron‐labeled and unlabeled immobilized C2C12 myoblast cells in vitro. Broadened but usable 31 P spectra were obtained and peak area ratios of resonances corresponding to intracellular metabolites showed no significant differences between labeled and unlabeled cell populations. We conclude that 31 P NMR spectra can be obtained from cells labeled with sufficient iron to permit visualization by 1 H imaging protocols and that these spectra have sufficient quality to be used to assess metabolic status. This result introduces the possibility of using localized 31 P MRS to evaluate the viability of iron‐labeled therapeutic cells as well as surrounding host tissue in vivo. Published in 2010 by John Wiley & Sons, Ltd.