Generation of rotational flow for formation of spheroid by using microfluidics device

Spheroid is important in the field of tissue engineering because it has a hole enabling efficient supply of oxygen and growth factors, and a vessel-like geometry is made by piling up it. But it is difficult to say that formation processes of toroidal-like spheroid is efficient, as most of them has done manually. In this study, we wish to suggest utility and possibility of applying microfluidics for formation of toroidal-like spheroid. The concept of our method is that cells are condensed by rotational flow in the microchannel and dielectrophoresis force. Some types of microchannels to generate rotational flow were designed with computer aided design (CAD) and analyzed with fluid analysis software. The superior microchannel was made, and NIH3T3 mouse embryo fibroblast cells suspension was flowed to it. As flow rates were changed, cells were rotated the microchannel just as our concept, and about 30% of them remained. This result support utility of our concept; toroidal-like spheroid can be formed under forces of rotational flow and dielectrophoresis.