A Method for Collecting Single Cell Suspensions Using an Ultrasonic Pump

The presence of cell aggregates in cell suspensions may reduce cell culture efficiency because they can induce apoptosis and inhibit proliferation. To avoid this problem, this study proposes a novel method for collecting single cell suspensions from culture chambers for subculture using an ultrasonic pump driven by the squeeze film effect. First, we developed a cell culture device consisting of a cell culture substrate with a piezoelectric ceramic disk glued to the back, so that we can elicit resonance vibration of the substrate. A glass pipe is then placed vertically against the cell culture substrate with a slight gap (corresponding to cell diameter) between the pipe and the substrate. By exciting an out-of-plane resonance vibration of the cell culture substrate, we can collect a cell suspension from the cell culture chamber. Since the gap distance between the glass pipe and the cell culture substrate corresponds to cell diameter, the collected cell suspension only contains single cells. We evaluated the capability of the developed cell suspension pumping system and the proliferation of the collected cells with C2C12 myoblast cells. The ratio of single cells in the cell suspension was improved by up to 9.6% compared with that of suspensions collected by the control method (traditional pipetting). Moreover, after cultivating the collected cells for 72 hr, the cells collected by our method proliferated 13.6% more than those collected by the control method. These results suggest that the proposed method has great potential for improving the cultivation efficiency of adhesive cell culture.