VivoTrax+ improves the detection of cancer cells with magnetic particle imaging

Cellular imaging is a rapidly growing field as novel tracers and imaging techniques are developed. Magnetic particle imaging (MPI) detects superparamagnetic iron oxide nanoparticles (SPIO), which can be used to label cells. The unique detection of SPIO-labeled cells boasts MPI as a sensitive modality; as such, the type of SPIO has a critical role in determining sensitivity and resolution. For cell tracking applications, the ideal SPIO should label cells efficiently and retain its sensitivity after cellular uptake. VivoTraxTM, a commercially available and commonly used SPIO for MPI, was recently re-released as VivoTrax+TM with an improved size distribution enriched for larger particles. In this study, VivoTrax+TM is shown to enhance cellular labeling and improve in vitro/in vivo sensitivity. Importantly, the sensitivity of both SPIO significantly decreased after cellular internalization. The results from this study emphasize the importance of translating SPIO performance in vivo to maintain its utility for cell tracking applications