In-Vivo Positive Contrast Tracking of Bone Marrow Stem Cells Labeled with IODEX-TAT-FITC Nanoparticles

Philip Lee¹, Bingwen Zheng¹, George Radda¹, Parasuraman Padmanabhan¹, Kishore Bhakoo¹

In vivo tracking with MRI has become standard in modern therapeutic cell studies. Typically, cells loaded heavily with iron-oxide nanoparticles, are identified as signal voids in T2*-weighted imaging. This raises two issues, namely the detrimental effect of high iron load in terms of cellular function and viability as well as interpretation ambiguities associated with partial volume artifacts and local magnetic field inhomogeneities. TAT-IODEX-FITC nanoparticles offer dual modality detection (MRI and optical) without adverse impact on cellular biology. By utilizing a multiple-echo ultra-short echo-time pulse sequence, we obtain high positive contrast of labeled bone marrow stem cells injected into rats striatum in vivo.