Label-free cell aggregate formation based on the magneto-Archimedes effect

This letter demonstrates formation of cell aggregates by a label-free three-dimensional (3D) cell assembly method, which is based on the magneto-Archimedes effect. Gadolinium complex was added to the culturing medium to enhance the diamagnetic property of the cells, by which label-free magnetic manipulation became possible. Cytotoxicity of the gadolinium complex was confirmed to be sufficiently low for exposure less than one day. With this method, the cells aggregated into an egg-shape in about 20 min and became a spheroid in one day. These results suggest that this method is a promising approach to construct arbitrarily-shaped 3D tissues. (C) 2011 American Institute of Physics. [doi:10.1063/1.3581883]