Protocol for Culturing Cells in the Bottom Channel
Assemble device in hood (see ALine Modular Device Assembly), place devices in clamp and keep in sterilized petri dish. Let sit under UV light for 20 minutes (Leave lid off the petri dish to allow sufficient UV exposure).
Roll a Kimwipe and generously wet with DI water, spray with ethanol to sterilize or use sterile water, and place around the device(s) inside the petri dish for humidity control. If you spray with EtOH, be sure to let EtOH evaporate before adding cells.
Add 20 μL of coating solution to the bottom channel of the device. Please refer to ALine Modular Device Geometry for surface area. Use the full surface area. For collagen type 1, coat at 25 µg/cm^2 and for fibronectin, coat at 5 µg/cm^2. Be careful to avoid bubble formation.
Note: some solutions may require a precoat of the chip, prior to device assembly.
We prefer to pipet holding the device at an angle, pipetting into the bottom port, as shown in image and video link below, to help avoid bubble formation in the bottom channel. You can stabilize the device in the clamp with your finger gently pressed on the back of the device.
Be sure there is no air at the end of pipet tip prior to inserting into the port. Only push to the pipet’s first resistance to avoid adding air into the channel.
If a bubble does form in the channel, hold the device at an angle and pipet 100 µl through the channel more aggressively to push it out. Pipetting too aggressively can burst the membrane, however. Finding the right amount of force will come with experience.
Add 50-80 µl media to the top well, just enough to coat the surface. The cells need this to adhere and survive.
Seed cells at 40,000 cells/cm^2 into bottom channel (or at optimized seeding density for your particular cell type). Please refer to ALine Modular Device Geometry for surface area and channel volume. Use the top or bottom surface area only. Note the effective area is less than for the coating solution. While the coating solution coats all surfaces, the cells settle on the bottom surface only.
I calculate seeding density using the channel capacity of 10 µl. However, I pipet 20 µl into the channel to avoid bubble introduction.
Be sure not to spill into the top well. Rinse well thoroughly if spilling occurs.
For culturing cells on the top surface of the channel, flip the device over. We set the device upside-down in their clamps (see video and image below). This raises the device off the petri dish and allows gas exchange while cells adhere to the membrane.
Cover with lid and incubate at 37°C, 5% CO2 for two hours.
After 2 hours, replace media in the channel. For culturing cells on the top surface of the channel, flip device back to its normal orientation at this point, as the cells should be adhered to the top surface. Rinse the top well and fill with 100 µl of media. For co-culture, cells can be added to the top well at this point or later, depending on growth kinetics.
Be sure not to spill into the top well when pipetting into the channel. Rinse well thoroughly if spilling occurs.