Regenerative medicine scientists at the Wake Forest Baptist Medical Centre have printed an ear as well as bone and muscle structures with a 3D printer. The scientists now confirm that printing a living tissue to replace injured or dead tissue is finally possible.
The Integrated Tissue and Organ Printing System (ITOP) deposits biodegradable plastic-like materials to form the shape of the tissue, and water-based gels, which contain the cells. The team has been developing this for 10 years and is better than current printers that are based on jetting, extrusion and laser-induced forward transfer that do not produce strong enough tissue structures. Additionally, the printing process does not harm the cells.
The team optimised the water-based ink and printed a frame of micro-channels to promote cell growth and health and ensured that the implanted structures survive long enough to integrate with the body. Oxygen and nutrients passed through these channels and distributed to the structures while the system of blood vessels is still developing.
The researchers implanted the printed muscle tissue in rats. They found that the muscle was structurally-sound after only two weeks. These turned into functional tissue and developed blood vessel systems. The scientists add that all the structures will be perfectly suitable for humans.
Another test involved constructing human-sized bone structure using human stem cells. The structure developed vascularised bone tissue after five months.
The ITOP system uses data from CT and MRI scans to customise the tissue to match a specific patient. Scientists used to print smaller tissue structures, which were smaller than 0.007 inches and without the blood vessels to survive before. This new study showed that creating a 1.5-inch ear structure can survive.
“This novel tissue and organ printer is an important advance in our quest to make replacement tissue for patients,” senior author Anthony Atala, director of the Wake Forest Institute for Regenerative Medicine (WFIRM), says in a statement. “It can fabricate stable, human-scale tissue of any shape. With further development, this technology could potentially be used to print living tissue and organ structures for surgical implantation.”