Abstract

4D Bioprinting: A New Paradigm for Engineering Complex Tissues

Fabien Guillemot, CEO, Université Victor Segalen Bordeaux 2

Dealing with tissue complexity and reproducing the functional anisotropy of human tissues remain a puzzling challenge for tissue engineers. Emergence of the biological functions results from dynamic interactions between cells, and with extracellular matrix. The important literature showing that cell fate (migration, polarization, proliferation…) is triggered by biochemical and mechanical signals arising from cell microenvironment suggests that tissue formation obeys to short range orders without reference to a global pattern. In that context, the winning tissue engineering strategy might rely on controlling tissue organization at the cell level. Emerging during the last decade, Bioprinting has been defined as “the use of computer-aided transfer processes for patterning and assembling living and non-living materials with a prescribed 2D or 3D organization in order to produce bio-engineered structures serving in regenerative medicine, pharmacokinetic and basic cell biology studies”. From a technological point of view, the Laser-Assisted Bioprinting (LAB) technology has been developped as an alternative method to inkjet and bioextrusion methods, thereby overcoming some of their limitations (namely clogging of print heads or capillaries) to pattern living cells and biomaterials with a micron-scale resolution. By harnessing this high printing resolution, we observe that tissue self-organization over time depends on the cell patterns initially printed by LAB, as well as cell types. To engineer complex tissues, we then emphasize the need to consider the spatio-temporal dynamics of tissue self-organization when designing blueprints.