Reconfigurable microfluidic device with discretized sidewall

Abstract

Various microfluidic features, such as traps, have been used to manipulate flows, cells, and other particles within microfluidic systems. However, these features often become undesirable in subsequent steps requiring different fluidic configurations. To meet the changing needs of various microfluidic configurations, we developed a reconfigurable microfluidic channel with movable sidewalls using mechanically discretized sidewalls of laterally aligned rectangular pins. The user can deform the channel sidewall at any time after fabrication by sliding the pins. We confirmed that the flow resistance of the straight microchannel could be reversibly adjusted in the range of 101–105 Pa s/μl by manually displacing one of the pins comprising the microchannel sidewall. The reconfigurable microchannel also made it possible to manipulate flows and cells by creating a segmented patterned culture of COS-7 cells and a coculture of human umbilical vein endothelial cells (HUVECs) and human lung fibroblasts (hLFs) inside the microchannel. The reconfigurable microfluidic device successfully maintained a culture of COS-7 cells in a log phase throughout the entire period of 216 h. Furthermore, we performed a migration assay of cocultured HUVEC and hLF spheroids within one microchannel and observed their migration toward each other.

Reconfigurable Microfluidic Channel with Pin-discretized Sidewalls

“…However, strong capillary action acting on the small gaps between pins connecting the inside and outside of the microchannel causes leakage of any liquid entering the pin gap, causing media evaporation, bacterial or cytotoxic contamination, and eventually cell death. Therefore, we have developed leak-free discretized sidewall-type reconfigurable microfluidic channels that withstand cyclic pin actions and long-term cell culture 10 .…”