A 3D scaffold for living cells

‘So far, there are two very different methods for the artificial production of tissue,’ explains Aleksandr Ovsianikov. ‘Either you use prefabricated three-dimensional structures as a scaffold to which cells are then attached, or you first create cell layers or even spherical clumps from many cells, which you then use as building blocks to assemble a larger tissue.’

Both methods have advantages and disadvantages: A prefabricated scaffold, as can be produced with high-precision 3D printers, offers mechanical stability and provides the desired shape, but the cells are often very slow to migrate through such a scaffold to form the tissue. The scaffold must be gradually degraded in a controlled manner, at the exact rate at which the tissue produces the so-called ‘extracellular matrix’, which then provides stability instead of the scaffold - this is also not easy to achieve.

If, on the other hand, you first produce larger layers or spheres from many cells and then join them together, the cell density is much higher right from the start, which saves a lot of time. On the other hand, the mechanical stability is lower and the cells can be easily destroyed. Both methods are now being combined at TU Wien: ‘We want to use robust, porous 3D scaffolds that contain multicellular building blocks right from the start,’ explains Ovsianikov. ‘This gives us a large number of cells right away and we don't have to wait for the cells to penetrate the structure. At the same time, the structure offers stability, but is so porous that the multicellular building blocks can grow together to quickly form a tissue.’

The technology of 2-photon lithography, a process for the high-precision production of tiny structures in 3D printers, which has been undergoing significant further development at TU Wien for years, is crucial for this. The Faculty of Mechanical and Industrial Engineering works closely with the Faculty of Technical Chemistry.