2.0 ml of 35 nm Coumarin labeled iron-based superparamagnetic contrast agent packaged in a 2 ml sealed serum bottle. 2 mg Fe/ml having a zeta potential of ~ +30 mV. Labeled cells may be visualized using a standard DAPI filter set. Molday Ion Coumarin has an excitation and emission maxima at 356 nm and 456 nm, respectively.