MAGNETIC RESONANCE IN MEDICINE, v.60, no.1, pp.1 - 7
Abstract
Rat glioma cells were labeled using electroporation with either manganese oxide (MnO) or superparamagnetic iron oxide (SPIO) nanoparticles. The viability and proliferation of SPIO-labeled cells (1.9 mg Fe/ml) or cells electroporated with a low dose of MnO (100 mu g Mn/ml) was not significantly different from unlabeled cells; a higher MnO dose (785 mu g Mn/ml) was found to be toxic. The cellular ion content was 0.1-0.3 pg Mn/cell and 4.4 pg Fe/cell, respectively, with cellular relaxivities of 2.5-4.8 s(-1) (RI) and 45-84 s(-1) (R-2) for MnO-labeled cells. Labeled cells (SPIO and low-dose MnO) were each transplanted in contralateral brain hemispheres of rats and imaged in vivo at 9.4T. While SPIO-labeled cells produced a strong "negative contrast" due to the increase in R-2, MnO-Iabeled cells produced "positive contrast" with an increased R-1. Simultaneous imaging of both transplants with opposite contrast offers a method for MR "double labeling" of different cell populations.