12-Aug-2016 - Fraunhofer-Institut für Grenzflächen- und Bioverfahrenstechnik (IGB)

Artificial skin tests for stopping sun damage

Sun rays damage unprotected skin. Substances in medications or lotions applied to the skin can be chemically modified by sun rays to have a toxic effect on the body. An accredited in-vitro test method at Fraunhofer IGB in Stuttgart measures the phototoxic potential of substances or cosmetics. The skin model was advanced with the addition of pigmentation that enables the testing of self-tanning agents.

Sunbathing without sunscreen can be dangerous. Sun rays do not only damage the skin. Some substances in drugs, cosmetics and medicinal herbs can be toxic to the skin when exposed to ultraviolet light. Experts call the phenomenon phototoxicity. It occurs when a substance absorbs light energy and is thereby chemically modified. Only the modified substance is toxic to the skin, which can cause redness, swelling or inflammation - similar to a sunburn. Companies can examine the phototoxicity of a substance with an in-vitro test methods developed at the Fraunhofer Institute for Interfacial Engineering and Biotechnology IGB. The test procedure is ISO certified and meets the required norms and standards.

Phototoxic substances - Feels like sunburn

The test procedure is performed on an in vitro skin model built at Fraunhofer IGB from human skin cells in special culture dishes. A fully developed epidermis model is used to study phototoxic effects. “We culture typical skin cell of the epidermis, such as human keratinocytes, in our dishes to form an artificial epidermis with all of its natural layers”, explained Sibylle Thude, the biologist who led the investigation into the accreditation. “The typical horny layer of the skin developes on the top of the model, which acts as an important barrier against dehydration and environmental influences.”

Substances are tested on a mature epidermis model by applying them to the surface of the epidermis and exposing the model to defined, but non-toxic, doses of UV radiation. The skin cells that create the model are then tested to verify if they are still alive or have been damaged. “We first look at the skin models under the microscope“, explained Thude. Each sample is then examined with a spectrometer to precisely quantify the extent of cell damage. “If the vitality of the skin model is damaged by more than 30 percent when compared to a non-irradiated model, we classify the test substance as a phototoxic”, said Thude. The test method is validated for aqueous solutions and oils, to the OECD Guideline 432 and the INVITTOX protocol 121, and assessed by the German Accreditation Body (DAkkS).

Self-tanning with sunscreen

Another skin model helps discover substances that stimulate melanin production of the skin. Self-tanners are of great interest, since they not only tone the skin, but also help build the body's own UV protection. To identify those substances, researchers add melanocytes to the epidermis model. Melanocytes play an important protective role in human skin: In sunlight they form the pigment melanin which adsorbs harmful UV radiation and thus prevents sunburn. “We irradiate the pigmented skin model with UV light to directly measure increased melanin production,“ explained Thude. They also measure melanogenic substances such as L-dihydroxy-phenylalanine which is a precursor of melanin. Skin lightening substances, such as creams that hide aging spots, can also be tested on the pigmented skin model.

Since 2013, cosmetics whose ingredients have been tested on animals can no longer be sold within the EU. The Fraunhofer IGB develops alternatives based on human cells to verify the biocompatibility of substances.

Fraunhofer-Institut für Grenzflächen- und Bioverfahrenstechnik (IGB)

Request information now

Recommend news PDF version / Print

Share on

Facts, background information, dossiers
  • skin
  • artificial skin
  • skin models
  • In-vitro tests
More about Fraunhofer-Institut IGB
  • News

    Retina-on-a-chip provides powerful tool for studying eye disease

    Impact statement: New technology that recreates some of the complexity of the human retina may help scientists study eye disease and screen for drug side effects that harm the eye. The development of a retina-on-a-chip, which combines living human cells with an artificial tissue-like system ... more

    New Process for Marker-free Cell Selection

    At this year’s analytica trade fair in Munich, three Fraunhofer Institutes will be presenting a project from pre-competitive research. Biologists, computer scientists and laser experts have developed a process to analyze and select cells and then examine their protein production. In pharmac ... more

    Rapid test identifies disease pathogens

    At present, bacteria, fungi or viruses can generally only be detected with certainty by way of elaborate laboratory tests or animal experiments. The food and pharmaceutical industries would like to have faster tests to check their products. Fraunhofer researchers are therefore developing a ... more

More about Fraunhofer-Gesellschaft
  • News

    Making the invisible visible

    Entangled photons can be used to improve imaging and measurement techniques. A team of researchers from the Fraunhofer Institute for Applied Optics and Precision Engineering IOF in Jena has developed a quantum imaging solution that can facilitate highly detailed insights into tissue samples ... more

    Use of low-energy electrons for innovative biotechnology processes

    The Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP has been utilizing electron-beam technology for decades in the development of cleaning, sterilization, and surface-modification processes and systems. Fraunhofer researchers from the Medical and Biotec ... more

    Tracking down polluters

    Proving criminal machinations can be difficult – for instance when those involved covertly discharge hazardous wastewater into sewers. A new sensor system developed by Fraunhofer researchers and their partners could soon help safety agencies establish wrongdoing: placed in a sewage canal, i ... more