A method of examining the skin can reduce the number of animal experiments while providing new opportunities to develop pharmaceuticals and cosmetics. Chemical imaging allows all layers of the skin to be seen and the presence of virtually any substance in any part of the skin to be measured with a very high degree of precision. A new study has shown that the technique can be applied to studying penetration and distribution of nickel in human skin and could provide novel insights into contact allergy.
More and more chemicals are being released into our environment. For example, parabens and phthalates are under discussion as two types of chemicals that can affect us. A new study from Chalmers University of Technology and the University of Gothenburg shows how what is termed chemical imaging can provide comprehensive information about penetration of nickel in human skin with a very high level of precision.
Investigations into how substances pass into and through the skin have so far taken place in two ways: by using tape strips to pull off the top "corneal" layer of skin for analysis, and through urine and blood testing to see what has penetrated through the skin. But we still know very little about what happens in the layers of skin in between. Chemical imaging allows us to see all layers of the skin with very high precision and to measure the presence of virtually any substances in any part of the skin. This can lead to pharmaceutical products that are better suited to the skin, for example.
With pharmaceuticals you often want as much as possible of the dose to be absorbed by the skin, but in some cases you may not want skin absorption, such as when you apply a sunscreen, which needs to remain on the surface of the skin and not penetrate it.
The researchers see opportunities opening up for replacing pharmaceutical tests which currently involve animal experiments. Chemical imaging provides more accurate results than tests on mice and pigs. Since it is not permissible to use animals to test cosmetics, this method also creates opportunities for the cosmetics industry.
"Many animal experiments carried out by researchers and companies are no longer necessary as a result of this method. If you want to know something about passive absorption into the human skin, this method is at least as good. It's better to do your testing on human skin than on a pig," says Hagvall.
The method can also provide a basis for determining the correct limits for harmful levels of substances that may come into contact with the skin. In order to establish those limits, you need to know how much of the dose on the skin's surface penetrates into and through the skin, which this method can show. It enhances our knowledge about what we are absorbing in our workplaces and in childcare facilities.
"The method can show everything with an image, whether you are looking for nickel, phthalates or parabens in the skin, or if you want to follow the drug's path through the skin. With just a skin sample we can essentially search for any molecules. We don't need to adapt the method in advance to what we are looking for," says Malmberg.
The group hope to apply their findings to haptens, small molecules linked to contact allergy, in the very near future.
This article has been republished from materials provided by Chalmers University of Technology. Note: material may have been edited for length and content. For further information, please contact the cited source.
Malmberg, P., Guttenberg, T., Ericson, M. B., & Hagvall, L. (2017). Imaging mass spectrometry for novel insights into contact allergy - a proof-of-concept study on nickel. Contact Dermatitis. doi:10.1111/cod.12911