Abstract

3D Laser Printing of Biomaterials and Living Cells

Boris Chichkov, Professor, Laser Zentrum Hannover

For 3d printing of biomaterials and scaffold generation, we apply two-photon polymerization (2PP) technique, which allows writing CAD structures directly into the volume of photosensitive polymer solutions. The polymerization occurs in the laser focus only. Thereby, resolutions below the diffraction limit down to the sub-100-nanometer range have been achieved. Scaffolds from different biomaterials like organic-Inorganic Sol-Gel-Composites (e.g., zirconium-hybrids), biodegradable polymers (e.g., polylactic acid (PLA), polycaprolactone (PCL), polyethylene glycol (PEG)), and hydrogels (e.g., gelatin, hyaluronic acid, chitosan, alginate, gellan gum) or hydrogel blends, have been generated with this technique. The effect of the micro-structure on cell behavior will be discussed. For arranging cells in 3D patterns, laser-assisted bioprinting (LAB) based on the laser-induced forward transfer process is used. Different cell types, including primary cells and stem cells embedded in hydrogels as extra-cellular matrix, have been printed. Thereby, 3D stem cell grafts, skin tissue, and cell patterns for studying cell-cell interactions have been generated. Both 2PP and LAB techniques are capable of advancing 3D cell culture towards CAD defined and precisely arranged 3D cell models and “organ-on-chip” systems. Such innovative 3D cell models could provide new insights in understanding of cell behavior, tissue functions and their regeneration. Printed tissue, for example skin, can be used for analyzing the effect of agents like pharmaceuticals or cosmetics ex vivo and, by applying human primary cells, it might be applied instead of animal tests.