It’s well known that unexposed skin is vulnerable to sun damage from prolonged or intense exposure, but how do you know sun-protective or skin products aren’t going to cause more problems than they solve? It’s thanks in part to the artificial skin tests used by researchers at places like the Fraunhofer Institute in Germany.
Sunscreen isn’t the only thing people apply to their bodies. Various cosmetics, pharmaceutical creams, and medicinal herbs are often applied topically. Although these products can be fine on their own, they can change and become toxic if exposed to ultraviolet light. For instance, certain antihistamines or cold-pressed citrus essential oils are “phototoxic” and will cause skin redness and inflammation similar to sunburn if they get enough sunlight exposure.
Since cosmetics with animal-tested ingredients cannot be sold in certain parts of the world, like the European Union, companies who want to make sure their products won’t cause phototoxic reactions have had to turn to artificial skin tests instead.
The test itself is relatively simple as far as biochemical cell reactions go. First, human skin cells are cultured in order to create the various layers needed to form an artificial epidermis. Then, the substance to be tested gets applied to the surface of the skin model.
The model is then exposed to a pre-determined level of UV radiation meant to simulate high but not normally toxic levels of sunlight exposure (i.e.: not enough to cause sunburn or other effect). The cells making up the skin model are then examined to see if any have been damaged or killed. A spectrometer can be used to define the exact extent of any damage.
When it comes to examining self-tanners and skin-lightening products, the artificial skin is infused with melanocytes, the human pigmentation cell. In addition to the normal test described above, the skin sample is also examined for pigment production levels.
Artificial skin tests are a useful midpoint between potentially prohibited animal tests and ethically-fraught human experimentation. No one wants their skin to experience sun damage, especially not from a product that’s meant to help them.
“Artificial skin tests for stopping sun damage,” Fraunhofer web site, August 10, 2016; http://www.igb.fraunhofer.de/en/press-media/press-releases/2016/artificial-skin-tests-for-stopping-sun-damage.html, last accessed August 12, 2016.