Magnetic Cell Labeling and Manipulation in Cell Cultures

Magnetic cell labeling has numerous applications in cell separation and sorting, tissue engineering and magnetic resonance imaging. Mammalian cells can be magnetically labeled by first biotinylating their cell membrane proteins and then binding streptavidin-coated paramagnetic particles onto the biotinylated proteins. Characterization studies indicated that the extent of cell biotinylation could be controlled by varying the biotinylating reagent concentration. Since the paramagnetic particles have high mass magnetization, the labeled cells were very responsive to magnetic field gradients and they could be targeted and patterned precisely using magnets. Magnetic multicellular spheroids were generated from these labeled cells and the constituent cells were found to be viable. These spheroids could be patterned using magnetic fields in a few seconds. This cell labeling methodology can be adapted to a wide variety of mammalian cell types. The labeled cells can then be manipulated in two dimensional cell culture or as three dimensional magnetic spheroids.