Design and Research on Microfluidic Impact Printing for Picoliter-sized Droplet

Using microfluidic chips to produce micro droplets wrapped with microorganisms is of great significance and value in life science research and analysis. One of the most obvious advantages is that it has a volume limiting effect on microorganisms. For example, tiny droplets of picoliter size can only allow single cells to enter, so that single cell separation in cell populations can be achieved. In this work, we designed a microfluidic impact printing system to encapsulate cells in Pico-liter level droplet (PL) through the inverse piezoelectric effect of piezoelectric materials. This method can isolate single cells in a label-free and high-throughput manner. The structure of the microfluidic chip designed in this paper can realize liquid feeding through capillary force without additional pumps and valves. The microfluidic chip and the driving module are not in direct contact, which avoids damage to cells activity. Experiments show that the system designed in this paper can stably generate 30PL, 12PL and 10PL droplet volumes in water, ink, and alcohol media respectively. The stable generation of picoliter-sized droplets provides an important basis for the subsequent research and development of single cell analysis.