Fig. 3

Computational results of steady CO₂ concentration in the microfluidic device placed in a stage incubator controlled at 5% CO₂. (a) CO₂ distributions on a horizontal cross section (z = 0 mm), generated by supplying gas mixtures containing 1, 5, 20, or 50% CO₂ to both gas channels for uniform CO₂ conditions, or by supplying gas mixtures with 1% and 50% CO₂ to the left- and right gas channels, respectively for a CO₂ gradient. (b) CO₂ concentration profiles along the center line of the media channel (y = 0 mm, z = 0 mm) under different CO₂ conditions. The variables c_L and c_R indicate the CO₂ concentration in the gas mixtures supplied to the left and right gas channels, respectively.