A Two-Step Bioreactor for Decellularized Lung Epithelialization.

Bioreactors for the reseeding of decellularized lung scaffolds have evolved with various advancements, including biomimetic mechanical stimulation, constant nutrient flow, multi-output monitoring, and large mammal scaling. Although dynamic bioreactors are not new to the field of lung bioengineering, ideal conditions during cell seeding have not been extensively studied or controlled. To address the lack of cell dispersal in traditional seeding methods, we have designed a two-step bioreactor. The first step is a novel system that rotates a seeded lung every 20 min at different angles in a sequence designed to anchor 20% of cells to a particular location based on the known rate of attachment. The second step involves perfusion-ventilation culture to ensure nutrient dispersion and cellular growth. Compared to statically seeded lungs, rotationally seeded lungs had significantly increased dsDNA content and more uniform cellular distribution after perfusion and ventilation had been administered. The addition of this novel seeding system before traditional culture methods will aid in recellularizing the lung and other geometrically complex organs for tissue engineering.