Long-term imaging of fibroblasts in a microfluidic device

Summary form only given. Understanding the long-term behaviour of cells is of considerable significance for cell biologists. This requires that the physicochemical environment is stable, which is difficult to achieve in conventional tissue culture incubators. Microfluidics devices can potentially provide a stable, highly controllable, environment. We have used long-term time-lapse imaging to observe the behaviour of fibroblast cultures in a microfluidic device. A suspension of 3T3 fibroblasts in DMEM media was loaded into a microfluidic channel of PDMS (polydimethylsiloxane), which was bonded poly-l-lysine treated glass. The device was maintained at 37°C and pH buffered media (5% C02) was delivered at a rate of 20nl/s. The cells were imaged with a 20x phase-contrast objective on an inverted microscope. Images were captured every 2 minutes for 84 hours on a camera (Point Grey 14S5M-C). Cells adhered to the surface and rapidly developed a typical fibroblast morphology, with large areas of flattened cytoplasm surrounding a centralised nucleus. Normal cellular behaviours were observed; including mitosis (for four generations), apoptosis and migration; and appeared to be unaffected by the flow of media (at 0.18mm/s). Over time they extended numerous filopodia and migrated across the glass surface with a mean velocity of 6μm/hr. These results suggest that cell cultures can be successfully maintained in a microfluidic environment and be subjected to a constant flow of media without adversely affecting cellular behaviours.