Now more than ever, as animal testing is banned, many industries are in great need of skin models. Unfortunately, even the largest international companies have limitations on the number of skin pieces that can be manufactured. Therefore, Jörg Saxler and Prof. Heike Mertsching have coordinated the Automated Tissue Engineering on Demand project within the Fraunhofer-Gesellschaft.
Mertsching heads the Cell Systems Department at the Fraunhofer Institute for Interfacial Engineering and Biotechnology (IGB) whereas Saxler heads the life science engineering business unit for the Fraunhofer Institute for Production Technology (IPT).
Instead of just a single layer skin model of a single cell type, the researchers have access to a patent-protected skin model that consists of two layers with different cell types. The researchers liken this model to a perfect copy of human skin and are in the process of developing the first fully automated process chain for manufacturing two-layer skin models.
In a multi-stage process, first small pieces of skin are sterilized. Then they are cut into small pieces, modified with specific enzymes, and isolated into two cell fractions, which are then propagated separately on cell culture surfaces. The next step in the process combines the two cell types into a two-layer model, with collagen added to the cells that are to form the flexible lower layer, or dermis. This gives the tissue natural elasticity. In a humid incubator kept at body temperature, it takes the cell fractions less than three weeks to grow together and form a finished skin model with a diameter of roughly one centimeter.
Because of the time and money associated with this process, the team at Fraunhofer is currently working to automate the work steps. The researchers at IGB and the Fraunhofer Institute for Cell Therapy and Immunology IZI are handling the development of the biological fundamentals and validation of the machine and its sub-modules. Experts from the Fraunhofer Institute for Manufacturing and Automation and IPT are taking care of prototype development, automation and integration of the machine into a complete functional system.
After working together for one year, the project team has already initiated eight patented procedures. The machine is expected to be finished in two years and the researchers hope to produce 5,000 skin models per month with the machine. IGB researchers also are working on a full-skin model that will include blood vessels for transplant purposes.