The use of biomaterial including living cells in additive manufacturing, is one of the most advance technology in tissue engineering and regenerative medicine. 3D bioprinting presents the capacity to produce efficiently and in a cost-effective way, tissues with cell density and shape recapitulating human tissue behaviours. Nevertheless, the use of LDM (liquid deposition modelling) technic presents limitations such as cells mortality, due to a high shear stress value inside the dispensing system.
In this study, we evaluated the biomaterial capacities to protect cells in our additive manufacturing process. The method is based on the relation between bioink viscoelastic properties, sizing of deposition system and cells viability. To access the shear stress map inside the bioprinting system, a specific algorithm was developed based on Poiseuille tube flow of a pseudoplastic power law fluid. Different cells source were used and their capacity to withstand stress investigated. Living and labelled necrotic cells were counted before and post-printing process to evaluate cell viability and total cell recovery in various conditions.
In view of results, the shear stress gradient can be controlled through bioink rheological behaviour and sizing of dispensing system. Cells viability seems to be directly related to shear stress value but also duration. In any case, it was shown that using adequate bioink rheological properties, cells viability can be optimal whatever the dispensing system and the applied flow value; protecting cells during the 3D bioprinting process.
In future, building an experimental data library will allow biomaterial engineers to use the algorithm in reverse engineering mode, to tailor 3D bioprinting system and/or biomaterials properties according to cells source. This approach will represent a disruptive innovation for patient specific surgery using autologous living implants.