3D printing enables breakthrough in lab-grown human hair

Researchers from the Columbia University Irving Medical Center are making headway in their work to treat human baldness thanks to 3D printing. The team, led by Angela Christiano, PhD, has found a way to grow human hair in a dish using stem cells and 3D printed plastic molds that mimic the natural microenvironment of hair follicles. The breakthrough could make hair restoration surgery more accessible and enhance drug discovery practices at pharmaceutical companies.

Growing hair from human cells in a lab has remained a distinct challenge in the biomedical research world, for reasons that are not totally clear. “Cells from rats and mice grow beautiful hairs,” Christiano explained. “But for reasons we don’t totally understand, human cells are resistant.”

For the first time, however, scientists have successfully generated human hair follicles in a dish without the need for skin implantation. This achievement is owed in part to 3D printing technologies, which enabled the research team to closely recreate the 3D environment that human hair cells live in.

Earlier on in the research, the team attempted to grow the cells inside hanging drops of liquid, but found results to be unpredictable, with some test mice growing hair after implantation and others not.

More recently, the team turned to 3D printing to create a more natural microenvironment for hair follicle growth. Specifically, the team used the technology to print plastic molds with long extensions measuring just half a millimeter in width.

Erbil Abaci, PhD, first author of this study, said: “Previous fabrication techniques have been unable to create such thin projections, so this work was greatly facilitated by innovations in 3D printing technology.”

With the 3D printed molds, the researchers were able to engineer human skin to grow around them and hair follicle cells from human volunteers were deposited into the extensions along with cells that produce keratin. The cells were then provided with growth factors, including JAK inhibitors. After just three weeks, the lab-grown human hair follicles starting creating hair.

Though the technique has seen early success, the process still needs to be optimized. In the future, the researchers believe the approach could generate an unlimited source of new hair follicles for patients undergoing robotic hair restoration surgery—which typically transfers hair follicles from the back of the head to the front and top meaning that it is dependent on how much hair the patient has.

“What we’ve shown is that we can basically create a hair farm: a grid of hairs that are patterned correctly and engineered so they can be transplanted back into that same patient’s scalp,” Christiano said. “That expands the availability of hair restoration to all patients—including the 30 million women in the United States who experience hair thinning and young men whose hairlines are still receding. Hair restoration surgery would no longer be limited by the number of donor hairs.”

The lab-grown follicles could also be used by the pharmaceutical industry in screening and discovering new hair growth drugs.

The full study, entitled “Tissue engineering of human hair follicles using a biomimetic developmental approach,” was recently published in the journal Nature Communications.