Rat lungs were first decellularized over a 3 day period. The resulting scaffolds were either statically or rotationally seeded for 3 hours. Statically-seeded lungs were transferred into the main chamber of the perfusion-ventilation system and left at 37° C overnight. Alternatively, to encourage cell distribution, decellularized lungs were also placed in a 50 mL conical tube (Step 2B, part C) on two cylinders for periodic rotation. A stepper motor (Step 2B, part C) controlled by a programmed Arduino microcontroller rotated one cylinder (Step 2B, part B) and subsequently the lung within the tube systematically every 20 minutes for 3 hours.