Fig. 1.

(A) A schematic of the perfusion system with feedback from the flow meter controlling the flow of culture medium into the microfluidic cell culture device (MFCD). Transfection mixture from the reagent reservoir is pushed into the injection loop by gas from the pressure regulator; once it has filled the loop, the valve will switch and reagent will move into the chip. (B) The two possible positions of the injection valve: X = reagent loading into loop, and Y = reagent injection into the microfluidic cell culture device.