A team of tissue engineers and plastic surgeons in China have created new ears for five children using a combination of autologous cell culturing and 3D printing.
The first patient, a girl who was 6 years old when the process began, now has a realistic-looking ear and suffers no serious side effects 2.5 years after implantation.
She and the other four patients were all born with unilateral microtia – a congenital deformity that results in an undersized and malformed outer ear. The current treatment option for microtia involves harvesting cartilage from the patient’s ribs and carefully shaping the tissue into an ear shape.
Unfortunately, this method “inevitably leads to donor site injury, and replicating the complex 3D ear structure is hard to achieve using surgeons' hand skill,” according to the group’s paper, which is published in EBioMedicine.
Following the 1997 breakthrough of the “Vacanti mouse”, medical researchers have been experimenting with using the body’s own cells, combined with a structural scaffold, to create refined and functional replacements for human organs. The pioneering technique described represents the first time human ear-shaped cartilage has been grown in vitro (outside a living body) and then surgically implanted.
To begin, the group took detailed CT scans of each patient’s healthy ear. They then used design software to mirror the images and convert the shape into a 3D-printed mold. Next, the mold was cast with a porous, biodegradable material called PGA. A more rigid material called PCL was used to reinforce the core of the scaffold.
With a polymer "skeleton" of the patient’s desired ear ready to go, cartilage-producing chondrocyte cells were isolated from the malformed ear tissue. After the cells had multiplied sufficiently, they were spread into the molds and incubated with a steady diet of growth factors. During this 12-week process, the chondrocytes began to form collagen and elastin fibers within the spongy PGA lattice.