A microfluidic study of mouse dendritic cell membrane transport properties of water and cryoprotectants

Dendritic cells (DCs) are antigen presenting cells that have been increasingly used in immunotherapy treatment of various diseases and have a great potential for cancer vaccine preparation. Cryopreservation and banking of DCs is critical to facilitate flexible and effective immunotherapy treatment. Therefore, determination of water and cryoprotectant transport properties of DC membrane is indispensable for developing optimal conditions for DCs cryopreservation. Using mouse DCs (mDCs), membrane transport properties were investigated using a microfluidic perfusion system which has recently been developed and fabricated by soft lithography. Cells in the microfluidic system were perfused with various hyperosmotic solutions in the presence or absence of cryoprotectant. The kinetics of cell volume changes under various extracellular conditions were monitored by a video camera and analyzed using a biophysical model to determine water and cryoprotectant transport properties of the cell membrane as well as associated activation energies. It was also shown from this study that the microfluidic perfusion system readily allowed us to: (1) quickly change or manipulate extracellular environment of cells; (2) confine cells in a monolayer channel which prevents imaging ambiguity; and (3) study cell membrane transport kinetics and properties.