Photo: Lindsay France/Cornell University Photography

Some stem cell research critics are uncomfortable with the idea of bioengineering parts of the body. But what about printing them?

Researchers led by Lawrence Bonassar at Cornell University are working to treat children with microtia, a congenital ear deformity that leaves the outer ear malformed and sometimes covers the hole leading to the inner ear. Some children with the deformity have no outer ear at all and most are left with limited hearing in the affected ear.

Bioengineering ears for kids with the disorder has turned out to be a metaphorical and literal flop, with ears losing their structure over time. The alternative is surgery that involves harvesting cartilage from the child’s ribcage, a procedure that is often fraught with complications and uses a limited supply of cartilage.

So Bonassar and his associates turned to a newly-developed technology: 3-D printing. Researchers make a map of the child’s healthy ear, create a mold to match on the opposite side, and let the printer do the rest. The printer uses animal cartilage and collagen as its “ink” to craft the ear, so it’s technically a living thing, not just a plastic or silicon prosthesis. The ear then incubates for about a month, hardens into cartilage and is surgically implanted in the patient.

So far researchers have found that the ear responds beautifully to its new host and keeps it’s shape. Bonassar and his team still aren’t sure if the ear will grow with the young patient (most of whom are around 5 or 6 years old), but says a new ear can be easily made to replace the old one when the child starts hitting those growth spurts.