Scientists have successfully printed a functional human ear that is ready for transplanting. This remarkable achievement was made possible by the recently debuted Integrated Tissue and Organ Printing System (ITOP) designed by a research team led by Anthony Atala from Wake Forest Institute for Regenerative Medicine to replace damaged or missing body parts. The team further demonstrated ITOP’s capabilities by 3D printing a jaw bone, muscle tissue, and cartilage structures.
The ITOP system creates its artificial human body parts in a manner similar to other 3D printers, which apply layer upon layer to build a product in a process called additive manufacturing. Rather than plastic or metal, ITOP uses specially designed biomaterials that closely emulate the structure of actual living tissue. Prior to ITOP, existing printers were challenged by the need to create tissues of sufficient strength. Artificial tissues also cannot receive necessary nutrients and oxygen without accompanying red blood vessels, which have proven difficult to manufacture at the appropriate size. “Cells simply cannot survive without a blood vessel supply that’s smaller than 200 microns [0.07 inches], which is extremely small,” says Atala. “That’s the maximum distance. And that’s not just for printing, that’s nature.”
To solve these problems, the ITOP system injects new methodology and technology into the process. A biodegradable polymer material is first printed to provide shape to the nascent tissue and is then filled with a non-toxic gel which contains the living cells. The ITOP also imprints microchannels throughout the tissues so that the processes necessary for keeping a cell healthy and alive are possible. “We basically recreated capillaries, creating microchannels that acted like a capillary bed,” says Atala.
The ITOP-produced body parts have been tested on live animals to determine its structural integrity. Results so far are positive, though there is a long road ahead. “We’re still looking at the safety of these things,” says Atala. “It’s still going to be a while—we still have to go through a lot of testing.”