The hype around 3D printing has been so intense in recent years that it's been touted as a solution to almost every human and manufacturing problem. However, to The Engineer’s knowledge, until now it has never been suggested as a cure for hair loss, but a dermatologist at Columbia University in New York is claiming just that.
The researchers have been trying to find why cells taken from the base of human hair follicles do not sprout hairs when cultured in the lab. "Cells from rats and mice grow beautiful hairs," said Angela Christiano, a professor of dermatology at Columbia’s Vagelos College of Physicians and Surgeons. "But for reasons we don't totally understand, human cells are resistant."
Culturing follicular cells until they grow hair and then transplanting them into the scalp would be an effective treatment for hair loss, which affects men and women.
Christiano's approach to the problem has been to try to recreate the conditions in which human follicles grow in the lab. An early attempt, in which she created small clumps of cells inside hanging drops of liquid produced unpredictable results, so she turned to 3D printers to try to create a more natural microenvironment.
In a paper in Nature Communications, Christiano and colleagues including Colin Jahoda, a bioscientist from Durham University, explain how they used 3D printers to replicate the shape of the environment in which follicular cells develop in hair bearing skin. The key factor in the shape was that the wells in which the cells were cultured featured a long, thin extension half a millimetre wide above the cell. "Previous fabrication techniques have been unable to create such thin projections, so this work was greatly facilitated by innovations in 3D printing technology," said Erbil Abaci, first author of the Nature paper.
The team placed hair follicle cells into the wells and then placed more cells on top that produce keratin, the protein from which hair is made. The wells were then dosed with growth factors to encourage hair production. After a three-week culturing period, hair began to grow.
Although the process still needs to be optimised, Christiano and team are confident that it could lead to a more effective process for producing implantable hair-bearing skin. At the moment, hair restoration surgery requires transplantation from an area where hair growth is stable enough for it to "take" in a new location, and as such is usually only possible in men whose hair loss has stabilised and still have enough hair (at the back of the head, for example) to donate – generally, some 2000 healthy follicles are needed growing dense hair for a transplant to be successful. Hair transplants in women are much more difficult, because their patterns of hair loss are different from those in men.
"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."
Another possibility for the technique is to create a laboratory environment in which hair restoring drugs could be screened and tested. No such research tool currently exists: the only drugs effective and licensed for hair restoration were not found by deliberate screening, but was a serendipitous discovery during the testing of active ingredients for a different conditions.
The video below shows how the team achieved its goal, while also providing an explanation for Prof Cristiano's interest in hair: