• Posted April 1, 2024

Scientists Get Closer to Realistic Replacement Human Ear

Researchers say they are close to perfecting a bioengineered, 3D printed replacement human ear that looks, feels and resists injury like the real thing.

Such an advance would greatly benefit people with congenitally malformed ears from birth, or those who have had an ear lost or damaged through injury, says a team at Weill Cornell Medicine in New York City.

Right now, "ear reconstruction requires multiple surgeries and an incredible amount of artistry and finesse,” said senior study author Dr. Jason Spector, a professor of surgery at Weill Cornell.

"This new technology may eventually provide an option that feels real for thousands needing surgery to correct outer ear deformities," said Spector, who is also chief of plastic and reconstructive surgery at NewYork-Presbyterian/Weill Cornell Medical Center.

As it stands, surgeons typically build a child's replacement ear using tissue from the child's own ribs, a painful and scarring procedure. The resulting graft might resemble a real ear, but it lacks an ear's natural flexibility, the Weill Cornell team explained.

The ear's underlying structure is made of flexible cartilage, and one way to create a new ear from scratch is to harness the power of cells that make cartilage, called chondrocytes.

In earlier work, Spector's team tried to use animal-derived chondrocytes to "seed" an ear-shaped scaffold made of collagen (a component of cartilage).

Unfortunately, those grafts failed to replicate the shape and structure of the ear.

“Because the cells tug on the woven matrix of proteins as they labor, the ear contracted and shrank by half,” Spector explained in a Weill-Cornell news release.

So it was back to the drawing board for the team. This time, they first created a detailed, intricate plastic scaffold mimicking the human ear, using 3D printing.

Next, they loaded sterilized animal-derived cartilage onto this scaffold, first making sure it would not trigger immune system rejection.

The cartilage acted as a reinforcing structure for any new tissue that later colonized the bioengineered ear.

This time round, it took about three to six months for the structure to form cartilage that more faithfully recreated the familiar ridges, curves and whorls of the human ear, Spector's team reported recently in the journal Acta Biomaterialia.

Biomechanical testing in a lab at Cornell's Ithaca campus appeared to confirm that the new cartilage was as flexible and elastic as typical ears.

However, the replacement ears aren't as durable as the real thing, tearing more easily, the researchers noted. Spector's group believe this issue can be solved by the addition of chondrocytes to the mix -- ideally, chondrocytes transplanted from the recipient's undamaged ear. That might make the replacement ear "biomechanically" more similar to the original ear, the team said.

More information

Find out more about the outer ear at UT Health Houston.

SOURCE: Weill Cornell Medicine, news release, March 29, 2024