Wake Forest Institute for Regenerative Medicine (WFIRM) scientists are the first to report using bioprinting to print a tracheal tissue construct comprised of multiple different functional materials. They printed different designs of smooth muscle and cartilage regions in artificial tracheal substitutes showing similar mechanical properties to human tracheal tissue.
Previous attempts of tissue engineered tracheal constructs have presented many different limitations, mainly because they focused only on using regenerated cartilage tissue. The WFIRM tracheal constructs are novel in that they were bioprinted with separate cartilage and smooth muscle regions at the same time using a biodegradable polyester material and hydrogels containing human mesenchymal stem cells which can self renew and can become a variety of cell types. In this case, the stem cells differentiated into two different cell types — chondrocytes and smooth muscles cells — in different regions of the bioprinted tracheal constructs. The cartilage portion is stiff to provide mechanical support to avoid collapse while the smooth muscle is pliable and connects the ends of the cartilage rings, allowing sufficient flexibility for airway contraction.