Cell size and deformation measurement using constrictions integrated into a microfluidic device

In this study, we developed a microfluidic device to evaluate cell size and deformability. As a specific method, a physical pushing load was applied to the cells using a channel having a constriction with a height of 1 μm. In addition, by orienting the constriction in a vertical direction, it was possible to measure the cell area easily using a microscope under load. The system constructed in this study can evaluate the contact area between the cells and the glass surface before and after applying a load under a microscope. The only input parameter was the syringe flow rate, and it was possible to evaluate multiple cells in a cell suspension simultaneously. Also, since the flow rate is 50 μm min or less, there is no need for a high-speed camera. This time, we evaluated cell types with different characteristics: NIH/3T3 and smooth muscle cells (SMC). To evaluate deformability, we focused on the circularity of the cells during load application. Due to the influence of the flow within the channel, cells with high deformability assumed an almost elliptical shape and flowed through the constriction. Using the device developed in this study, we confirmed that SMCs, which are muscle cells, have large variations in cell size and hardness among individual cells. Finally, we discussed these results and possible future applications.