Cell-based 3D-printed skin aims to replace animal testing

To meet the requirements of EU Directive 2010/63/EU, which restricts the use of animal testing in cosmetics, a joint research initiative by Graz University of Technology (TU Graz) and the Vellore Institute of Technology (VIT) in India is developing 3D-printed skin imitations made from hydrogel and living cells. The goal: to evaluate the absorption and toxicity of nanoparticles – such as those found in sunscreen – in a cell-based test system.  

The skin models developed by the research team replicate the natural three-layer structure and biomechanics of human skin. These models are fabricated using 3D printing technology and hydrogel formulations that allow the integration of viable skin cells. 

“The hydrogels for our skin imitation from the 3D printer have to fulfil a number of requirements,” explains Karin Stana Kleinschek from the Institute of Chemistry and Technology of Biobased Systems at TU Graz. 
“These cells not only have to survive but also have to be able to grow and multiply.” 

Hydrogels, known for their high-water content, provide favorable conditions for cell culture. However, the water content also requires advanced mechanical and chemical stabilisation methods, which are currently being developed at TU Graz. 

The team is focusing on bio-inspired cross-linking techniques to stabilize the 3D-printed structures. These methods are designed to work under gentle conditions and avoid the use of cytotoxic chemicals. Once stable, the hydrogel-based models are tested in India for resistance and cytotoxicity using in vitro cell cultures. 

To qualify as a skin model, hydrogel must support the development of skin tissue for at least two to three weeks in culture. Upon passing these tests, the models are ready for further studies involving nanoparticle testing in cosmetics. 

Initial tests of the printed hydrogel models have shown promising results. The materials are mechanically stable and do not exhibit cytotoxic effects. 

“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.” Future work will focus on refining the hydrogel formulations and validating their effectiveness as a reliable alternative to animal testing in research. 

 MEDICA-tradefair.com; Source: Graz University of Technology