An April 3, 2025 news item on ScienceDaily announces work that promises to bring researchers closer to ending nanoparticle cosmetic testing on animals,
A research team from TU Graz [Austria[ and the Vellore Institute of Technology in India is developing a 3D-printed skin imitation equipped with living cells in order to test nanoparticles from cosmetics without animal testing.
Directive 2010/63/EU laid down restrictions on animal testing for the testing of cosmetics and their ingredients throughout the EU. Therefore, there is an intense search for alternatives to test the absorption and toxicity of nanoparticles from cosmetics such as sun creams.
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An April 3, 2025 Graz University of Technology (TU Graz) press release by Falko Schoklitsch (also on EurekAlert), which originated the news item, provides more detail about this international collaboration
Hydrogels in which skin cells survive and grow
“The hydrogels for our skin imitation from the 3D printer have to fulfil a number of requirements,” says Karin Stana Kleinschek from the Institute of Chemistry and Technology of Biobased Systems. “The hydrogels must be able to interact with living skin cells. These cells not only have to survive, but also have to be able to grow and multiply.” The starting point for stable and 3D-printable structures are hydrogel formulations developed at TU Graz. Hydrogels are characterised by their high-water content, which creates ideal conditions for the integration and growth of cells. However, the high-water content also requires methods for mechanical and chemical stabilisation of the 3D prints.
TU Graz is working intensively on cross-linking methods for stabilisation. Ideally, following nature’s example, the cross-linking takes place under very mild conditions and without the use of cytotoxic chemicals. After successful stabilisation, the cooperation partners in India test the resistance and toxicity of the 3D prints in cell culture. Only when skin cells in the hydrogel survive in cell culture for two to three weeks and develop skin tissue can we speak of a skin imitation. This skin imitation can then be used for further cell tests on cosmetics.
Successful tests
The first tests of 3D-printed hydrogels in cell culture were very successful. The cross-linked materials are non-cytotoxic and mechanically stable. “In the next step, the 3D-printed models (skin imitations) will be used to test nanoparticles,” says Karin Stana Kleinschek. “This is a success for the complementary research at TU Graz and VIT. Our many years of expertise in the field of material research for tissue imitations and VIT’s expertise in molecular and cell biology have complemented each other perfectly. We are now working together to further optimise the hydrogel formulations and validate their usefulness as a substitute for animal experiments.”
Here’s a link to and a citation for the paper,
Protocol for the fabrication of self-standing (nano)cellulose-based 3D scaffolds for tissue engineering by Tamilselvan Mohan, Matej Bračič, Doris Bračič, Florian Lackner, Chandran Nagaraj, Andreja Dobaj Štiglic, Rupert Kargl, Karin Stana Kleinsch. STAR Protocols Volume 6, Issue 1, 21 March 2025, 103583 DOI: https://doi.org/10.1016/j.xpro.2024.103583 (Creative Commons Licence: CC by NC 4.0)
This paper is open access.