Microfluidic cell culture offers many distinct advantages, not least that scientists can work with expensive rare cells, use less reagent, and in many cases control the environment with greater accuracy than in bulk cell culture, petri dishes, or multiwell plates. Samuel Forry, Ph.D., research chemist, National Institute of Standards and Technology (NIST), talks about technology developed at his institution.
“At NIST we’re very interested in fundamental measurements and the way measurement can improve biology. I think we have demonstrated a level of control and ability to measure the microenvironment around cells, which is revealed in sensitivities to partial gas pressures that may not have been appreciated,” notes Dr. Forry.
To accomplish this, Dr. Forry and his colleagues have fabricated the microchamber and microfluidic compartments out of gas-permeable material—poly(dimethylsiloxane)(PDMS)—and routed them near each other. “We can then allow diffusion through the material to give us control over the partial pressure in the culture chambers where the cells are being cultured. We’ve shown this for oxygen and for CO2.”
Essentially, they create stagnant conditions but are able to supply sufficient gases to keep the cells from disrupting the homeostasis in the environment. “We perfuse media past the cells but do it only intermittently,” he notes. “It turns out conventional cell culture media has enough salts, amino acids, and sugars to last for a pretty long time, but the gas partial pressures get out of whack quickly. We control the gas partial pressures directly through the material.”
The most common use, according to Dr. Forry, “is where you want to create a hypoxic environment or maintain 5% CO2. We can also create gradients across a microfluidic chamber to create systems where one side of our chamber has normal oxygen level or maybe 21% and the other side has hypoxic conditions and one can look at the way cells respond in the two different environments side by side.”