A Biocompatible/ Biodegradable Cell Growth Environment
Tissue engineering and tissue regeneration is becoming a promising approach e.g. to cure severe bone injuries [Learn more…].
Artificial tissue grown from differentiable cells often needs to be in a particular 3-dimensional shape for implantation. Bioscaffolds can serve as a cell growth environment for artificial tissues, by supporting supply of the cells and removal of the metabolites. Usually bio-scaffolds consist of a porous material to be seeded with differentiable cells. After implantation in the host organism the scaffold material is designed to degrade,
Right image: A scaffold structure 36 mm by 36 mm with inner pitch of 1mm.
Up to now bioscaffolds of basic geometries have served as research platforms for cell biologists and material researchers. As complex 3D-geometry becomes increasingly important the BS3.1 supports this through the data filter for external STL files (E.g. CT data, external CAD software…)
BioInks fill the gap between a 3D printer and tissue engineering
Biopolymers for cell cultivation usually show a low viscosity. 3D structures of defined shape, however, require stiff materials with low cell viability potential. An contradiction in terms?
The picture presents one possible approach: Composites of two or three materials give home to cells in a “stiff” 3D environment.
Combined printing of very different polymers can be challenging for the printer: Different needle sizes, different print parameters for each needle. All this is available with BS3.1
Up to now commercial bioinks are expensive and not always working in a suitable manner. Our RESOURCES section lists publications of GeSiM customers/ partners working on biomaterials. Examples:
- Researchers at Technical Universität Dresden show how low-viscous alginate turns into a valuable bioink by adding Methylcellulose. (More…)
- A blend of PCL-PEG with ADA (Dialdehyde gelatine hydrogel) was investigated by the Biomaterial Resarch Group at FAU Erlangen. (More…)
- VELOX(R) bone substitute cement paste is based on calcium-phosphate and now commercially available from INNOTERE GmbH, Radebeul, Germany.
BS3.1 now is probably the worlds only bioprinter with built-in two-component extruder: A so called Core/Shell extruder produces “maccaroni” structures, e.g. for direct combination of a soft, cell-friendly polymer with an alginate of much higher viscosity.
Miniaturized Scaffolds from Biopolymers
Some applications require downscaling of 3D printing to get into the range of small organoids like blood vessels. BS3.1 offers tools for optimizing/ accomplishing standard pneumatic printing.
Solid biopolymers like PCL and PLA offer better 3D support than low-viscous bioinks and offer higher 3D resolution, respectively. The easiest way is to use the cartridge heater along with stainless steel cartridges and aluminum/steel needles.
Very thin needles plus high power: The High-Power-Syringe Extruder extends the range of the pneumatic system in terms of pressure (> 100 bar) and temperature (< 250°C).
Melt Electrospinning (MES) provides much smaller structures than pneumatic printing. It requires high electrical voltage (15…30 kV) between the dispense nozzle and the building platform.
The struts of the MES mesh have sizes down to 0.01 mm. PCL 50,000 was printed at a voltage of +30 kV and a pressure of 0.6 bar.