Scientists harness 3D-printed hair follicles in skin biomanufacturing breakthrough

20 Nov 2023 --- Scientists at Rensselaer Polytechnic Institute, US, have 3D printed hair follicles through tissue engineering. Documented in Science Advances, this technique pushes the boundaries of lab grown skin, marking a step forward in creating skin grafts and offering new opportunities in cosmetics testing.

“Right now, contemporary skin models — the engineered structures that mimic human skin — are quite simple. Increasing their complexity by adding hair follicles would give us even more information about how skin interacts with topical products,” says Dr. Carolina Catarino, first author of the study and researcher developing new skin testing methods at Grupo Boticário, a cosmetics company in Brazil.

While including hair follicles in engineered skin might seem “superfluous,” these structures are vital for skin function. Beyond regulating body temperature through sweat production, hair follicles house stem cells crucial for skin healing.

Moreover, hair follicles serve as entry points for topical drugs and cosmetics, making them indispensable in dermatological testing, underscores Rensselaer. This experiment marks an advancement from the first reconstructed skin models developed over five decades ago.

“None of the current reconstructed skin models available, for example, contain fully developed hair follicle units,” write the study authors.

Automated “bio-ink” manufacturing
The scientists initiated the experiment by cultivating skin and follicle cells in the lab until there were sufficient printable cells. The resulting “bio-ink,” composed of different cell types mixed with proteins and other materials, was deposited “layer by layer” using an extremely thin needle.

3D bioprinting of hair follicles within skin (Image credit: Rensselaer Polytechnic Institute).

As a result, the skin with integrated hair follicles began to form, mimicking the natural structure found in human skin.

“Our work proves that hair follicle structures can be created in a highly precise, reproducible way using 3D-bioprinting. This kind of automated process is needed to make future biomanufacturing of skin possible,” comments Dr. Pankaj Karande, study lead.

“The reconstruction of hair follicles using human-derived cells has historically been challenging. Some studies have shown that if these cells are cultured in a three-dimensional environment, they can potentially originate new hair follicles or hair shafts, and our study builds on this work,” continues Karande, associate professor of chemical and biological engineering and a member of Rensselaer’s Shirley Ann Jackson, Ph.D. Center for Biotechnology and Interdisciplinary Studies.

Evolving cosmetic testing and skin treatments
Although the current lifespan of the follicle tissues is limited to two to three weeks, the researchers envision extending this period to allow for the maturation of hair follicles. Hair follicles house stem cells crucial for skin healing.

“Dr. Karande’s lab is at the forefront of skin tissue engineering. This team has already successfully printed skin with working blood vessels, and this latest research is an exciting next step in developing and testing better treatments for burns and other skin conditions,” remarks Dr. Deepak Vashishth, director of the Shirley Ann Jackson, Ph.D. Center for Biotechnology and Interdisciplinary Studies.

Dr. Shekhar Garde, dean of Rensselaer’s School of Engineering, adds: “Dr. Karande’s work is a great example of advances being made by Rensselaer Polytechnic Institute researchers at the interface of engineering and life sciences with impact on human health.”

“Bringing multichannel 3D printing to the biological realm is opening exciting opportunities that would have been hard to imagine in the past.”

In the movement toward ending cosmetic testing on animals, fully developed artificial skin continues to present a viable alternative solution to the ethics issue.

By Venya Patel