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

Abstract

Labeling of cells with superparamagnetic iron oxide nanoparticles permits cell tracking by 1H MRI while 31P MRS allows non-invasive evaluation of cellular bioenergetics. We evaluated the compatibility of these two techniques by obtaining 31P NMR spectra of iron-labeled and unlabeled immobilized C2C12 myoblast cells in vitro. Broadened but usable 31P 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 31P NMR spectra can be obtained from cells labeled with sufficient iron to permit visualization by 1H imaging protocols and that these spectra have sufficient quality to be used to assess metabolic status. This result introduces the possibility of using localized 31P 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.