3D bio-printing: multi-nozzle dual-drive system for constructing complex 3D scaffolds with multi-biomaterials
Development of a sophisticated 3D bio-printing system capable of construction of 3D complex structural bio-architectures of multi-scale, multi-component, multi-material, and multi-functional attributes.
Additive manufacturing is one of the most promising routes to enable a wide range of development of products and prototypes. In order to build 3D complex scaffolds with multi-biomaterials for clinical application, a new 3D multi-nozzle system with dual-mode drives, i.e. ejection and extrusion was most desirable given the needs to maintain the live cells to be deposited simultaneously. Significant effort has been made to gain the refined control of droplets of wide range materials as inks, and excellent coordination during fabrication, together with specific processing parameters that influence the size and stability of droplets which demands intensive engineering inputs, let alone the considerations given to the wide range of biomaterials with different properties to be incorporated. The combination of precise control and coordination of various variables and parameters are required to facilitate the settings for certain-sized droplets, which are potentially eligible for bio-printing. The dispensing nozzles can work well both in independent and convergent mode, which can be freely switched between in order to fabricate scaffolds with multi-material of both low viscosity (by pneumatic dispensing) and high viscosity (through motor extrusion). It is anticipated that the system can satisfy clinical application, for instance, to construct bionic bone.
This 3D multi-nuzzle PAM-MAM system has been developed with the pneumatic system to provide the pneumatic source of positive pressure (for droplet formation) and negative pressure (to avoid salivation) with accurate regulation (± 0.1 kPa). PAM consists of three ink-jetting nozzles (Φ150 μm). For a single PAM, the plunger driven by air will force ink materials in micro-syringe to form droplets through the nozzle, also known as ejection. Besides, 2 of PAM nozzles can be freely switched between independent mode and convergent mode by motors. In convergent mode, they can focus on a point without any interference to provide availability for multi-materials. The actual fabrication process has been carried out to create the scaffold architectures to verify the technology developed.
A newly combined multi-nozzle system based on MAM and PAM was introduced. The influence of AP, HT and SA content on droplet size and stability was investigated in details. The results show that droplets by PAM jetting can be finely controlled with good precision (~Φ430 μm) and high stability (≥ 90%). The parameter sets for certain size can be easily obtained with the assistance of our database, regardless of the various properties of materials for PAM. Most of all, this system can deal with materials both of low and high viscosity with satisfying coordination and synchronization, making it highly potential to fabricate 3D complex scaffolds with multi-biomaterials and sufficient strength for tissue engineering. It is anticipated that this research can accelerate the practical and technical advancements for 3D organ printing in the near future.
Professor Changqing Liu - Professor of Electronics Manufacture
"This collaborative research has been initiated and undertaken through an international cross-disciplinary partnership with Huazhong University of Science and Technology (China)."