Gadonanotube materials as new intracellular MRI contrast agents for stem cell labeling

Stem cells possess great potential for different medical applications and every year more investigators join this field of study. As interest in stem cells has increased, it has become essential to track the cells in vivo in order to study their biodistribution and possible tissue accumulation. Here, we review the use of two new carbon nanotube-based contrast agents (CAs) for magnetic resonance imaging (MRI) called Gadonanotube (GNT) materials, which contain Gd 3+ -ion clusters or Gd 3+ chelates within the sidewall cavities of 20-80 nm long carbon nanotube (CNT) capsules. These ultra-high-performance T 1 -weighted CAs have been use to label a number of mammalian cells, including porcine bone marrow-derived mesenchymal stem cells without any observed cytotoxicity. Furthermore, various in vitro and in vivo preclinical studies have demonstrated the safety and potential of these new CNT-based materials as intracellular CA labels for stem cell tracking by MRI.