Small & Ultra-Small Nanoparticles of Manganese Oxide (SPMnO, USPMnO) for Positive Contrast in Cellular MRI

Marc-Andr Fortin^1,2, Mlanie Tremblay¹, Jean Lagueux², Mathieu Ltourneau¹, Luc Faucher¹, Dario Rojas¹

Ultra-small MnO nanocrystals were used to label cancer cells. To enhance the ingestion efficiency, the particles were coated with thiol-containing molecules. This strategy also allowed to tune the contrast agent from agglomerates (SPMnO) to individual nanoparticles (USPMnO). For both products, the cell labeling efficiency and MR contrast effect were compared with Mn2+. Labeling cells with (U)SPMnO is efficient, while preserving the viability of cells. Pellets containing as low as 10000 cells were visualized in 1T MRI. The strong positive contrast enhancement effect, normalized to the amount of Mn internalized in the cells, could be preserved over many division cycles.