Whitney Palmer

CHAPEL HILL — Lab experiments may never look the same if a local researcher succeeds in growing 3-D models of human skin that could replace animals in scientific testing.

Leena Nylander-French, an environmental sciences and engineering researcher in the UNC-Chapel Hill Gillings School of Global Public Health, uses foreskins from circumcisions performed at UNC Hospitals to create quarter-size human skin samples to test how chemicals penetrate and affect the skin.

“The biggest benefit is that it provides a more detailed understanding of human skin and its mechanisms,” Nylander-French said. “The knowledge will help protect us and show us how to get rid of various toxins.”

Mouse skins – those most common in testing – cannot accurately demonstrate how chemicals permeate human skin, she said. For example, mouse skin’s uppermost layer is two to five cells thick. Human skin’s uppermost layer is roughly 20 cells thick.

Nylander-French said her lab will build its first skin models this month. To construct the models, the team will separate

Scientists at UNC-Chapel Hill use skin cells from discarded circumcision tissue as an alternative to animal testing for cosmetics and other products. Photo Courtesy: MATTEK EPIDERM

the epidermis (the skin’s outer layer) from the dermis (the second skin layer) with enzymes. Then they’ll isolate cells selected to grow the model and attach them to a Petri dish. 

They will cover the cells with a collagen layer infused with fibroblasts – cells that prompt new dermis growth – as well as another cell layer of melanocytes and keratinocytes to give the new epidermis pigment and a protective coating.

To map where chemicals travel in human skin, Nylander-French said the team will embed models in wax and dye the layers different colors. Over several days, the team will drop small amounts of chemicals onto the models and track their migration.

According to Thomas Hartung, director of Johns Hopkins University’s Center for Alternatives to Animal Testing, the cosmetics industry has used artificial human skin models for nearly 20 years to test what substances irritate the skin. Nylander-French’s work could take this research a step further, he said.

“Artificial skin hasn’t been a strong barrier,” Hartung said. “We still need to optimize models because there are some substances that pass through the current models that wouldn’t pass through natural human skin.”