Abstract
Microfluidic technologies have enabled cell culture and various assays for medical diagnosis, drug-screening in a small space or in an in vivo-mimicking manner. Cryopreservation of cells on such microfluidic devices that enables long-term shipping and storage is still challenging but is important in realizing stable storage and supply of the devices. We developed a versatile microfluidic channel which simplified the whole cell cryopreservation processes from freezing to restarting culture therein. The polydimethylsiloxane (PDMS)-made microchannel has two wells with smooth walls, and the flow rates can be switched using either Laplace pressure- or hydrostatic pressure-driven flow. The microchannel has two wells: one is used to collect cells to be cryopreserved; another used to wash the cryopreservation medium around thawed cells followed by restarting cultivation. We confirmed that cells introduced into the microchannel were successfully collected at the well bottom using Laplace pressure-driven flow, whereas replacement of cryopreservation medium to growth medium after thawing and transferring the cells to another well for restart culture were simultaneously done using hydrostatic pressure. We also confirmed the viability of restarted culture of COS-7 cells cryopreserved in the microfluidic channel. The cells became near confluent three days after thawing the microfluidic device.
