What is the GeSiM BioScaffold printer used for?
|- Production of multi-material bioscaffolds with defined porosity|
- Printing of 3D bodies from biopolymers
- Sequential bioprinting with hard (PCL/PLA) and soft biopolymers (Hydrogels, alginate)
|- Application of living cells ("Organ printing"), either embedded in a biopolymer or seeded by the optional pipetting unit
- 3D Printing of bone replacement materials (Calcium phosphate, Hydroxyapatite)
- Printing of micro structures from biopolymers by melt electro spinning/writing
This section presents highlights of the work of our customers with GeSiM instruments for bioprinting. It is neither comprehensive nor can GeSiM be responsible for content and correctness.
Sequential Bioprinting with GeSiM Instruments
PCL (PolyCaproLactone) is a popular hard-phase biopolymer for tissue engineering and 3D printing. It is biocompatible and – to a certain extent – biodegradable. Multi-printhead instruments like the GeSiM BS31 easily combine PCL struts with cell friendly alginate/hydrogels.
Hard-phase biopolymers shall be optimized towards a quick degradation/mass loss when getting in contact with body fluid. An inherent drawback of pure PCL is the relatively high stability under physiological conditions. Here we present a recent study  addressing this problem. It was conducted using the predecessor of BS3.1, BS2.1.
PCL and polyethylene glycol (PEG) blends (PCL-PEG) together with alginate dialdehyde gelatine hydrogel (ADA-GEL) loaded with stromal cell line (ST2) were investigated.
The PCL-PEG blends showed a much faster degradation and a mass loss tending to be almost equal with the corresponding content of PEG being ~14% for the PCL-PEG 8020 and ~23% for the PCL-PEG 7030 compositions. The wetting behaviour and the cell behaviour were improved in comparison to pure PCL. Blends showed improved hydrophilicity and cell response with PEG blending increasing the degradation and decreasing the mechanical properties of the scaffolds.
 Tobias Zehnder, Tim Freund, Merve Demir, Rainer Detsch and Aldo R. Boccaccini: Fabrication of Cell-Loaded Two-Phase 3D Constructs for Tissue Engineering, Materials 2016, 9(11), 887
3D-printing of Cell-loaded Alginate Capsules suspended in Hydrogel
Printable biomaterials can benefit from complex compositions: The release of drugs or cell growth have to be controlled after printing. A group from the Friedrich-Alexander University in Erlangen added prefabricated capsules enriched with cells to hydrogel before printing.
The GeSiM BioScaffolder was part of this study. It presents a novel method to produce macroporous hydrogel scaffolds in combination with cell-loaded capsule-containing struts by 3D bioplotting.
This approach enables loading of the capsules and strut phases with different cells and/or bioactive substances and hence makes compartmentalization within a scaffold possible.
The goal was to produce scaffolds for possible applications in bone tissue engineering consisting of alginate struts containing alginate capsules enriched with MG-63 osteoblast-like cells and ALP (alkaline phosphatase). Two combinations were compared, namely ALP in the struts and cells in the capsules and vice-versa. Both combinations were cytocompatible for cells and mineralization of scaffolds could be detected in both cases, according to an OsteoImage staining. ALP had no adverse effect on cytocompatibility and enhanced mitochondrial activity.
Different components desirable for bone regeneration, e.g., cells and bioactive proteins, can be incorporated both in the capsules and struts. This enables compartmentalization of components, which facilitates greater flexibility in modification of the scaffold.
Rainer Detsch, Bapi Sarker, Tobias Zehnder, Aldo R. Boccaccini and Timothy E.L. Douglas:
Additive manufacturing of cell-loaded alginate enriched with alkaline phosphatase for bone tissue engineering application. De Gruyter, BioNanoMat 2014; 15(3-4): 79–87
The “Green Bioprinting” approach is expected to bring an advantage for existing applications of microalgae in the biotechnological field as, e.g. harvesting and separation procedures could be simplified and the co-immobilization of microalgae with (e.g. plant growth promoting) bacteria could be conducted in a spatially organized manner. In addition, this novel approach opens further possibilities for new, future-oriented applications such as the usage of microalgae or other plant cells in the medical field. The cocultivation of algae in close vicinity to human cells could enable a sustained delivery of oxygen or secondary metabolites with therapeutic potential to human cells without the need of external supply. The fabrication of patterned coculture scaffolds can be easily realized by two-channel plotting. 
In this study, conducted by GeSiM customers at the Centre for Translational Bone, Joint and Soft Tissue Research at the Technische Universität Dresden in collaboration with partners from the Institute of Bioprocess Engineering at the TU Dresden, a simple geometry was chosen to demonstrate embedding of microalgae in an alginate hydrogel scaffold by 3D plotting.
It was demonstrated that microalgae can be immobilized in 3D alginate-based scaffolds with predesigned geometry. The alginate matrix has proven its suitability for cultivation of the embedded algae—as indicated by cell growth and photosynthetic activity.  The immobilization of microalgae in the plotted structures resulted in an enhanced viability and stable growth rates even under suboptimal culture conditions. 
 A. Lode, F. Krujatz, S. Brüggemeier, M. Quade, K. Schütz, S. Knaack, J. Weber, T. Bley, M. Gelinsky: “Green bioprinting: Fabrication of photosynthetic algae-laden hydrogel scaffolds for biotechnological and medical applications”, Engineering in Life Sciences, Volume 15, Issue 2, pages 177–183, March 2015
 F. Krujatz, A. Lode, S. Brüggemeier, K. Schütz, J. Kramer, T. Bley, M. Gelinsky, J. Weber: „Green Bioprinting: Viability and growth analysis of microalgae immobilized in 3D-plotted hydrogels versus suspension cultures“, Engineering in Life Sciences, Volume 15, Issue 7, pages 678–688, October 2015
Centre for Translational Bone, Joint and Soft Tissue Research
Technische Universität Dresden
The Instant Recipe for Tissue Engineering?
The group of Prof. Michael Gelinsky at the Technische Universität Dresden conducted a study to overcome the limitations of biofabrication with cell-friendly TE Materials. The aim of the study was to develop a plotting material that is based on alginate, the probably most popular substrate material for biological 3D printing. The goal was to find a composition optimized both for printing and for cell embedding.
Basically a rather easy approach was used: Addition of Methylcellulose (MC) to low concentrated alginate. That leads to an enhanced viscosity and therefore improved printing conditions. The MC did not contribute to the gelation and was released from the scaffolds during the following cultivation. Mesenchymal stem cells were added to the alginate-MC blend and showed high viability after several weeks of cultivation within the plotted scaffolds.In this work both cytocompatibility and mechanical properties of the alg/MC material were investigated. The developed plotting material allows to print 3D objects in the centimetre range and even complex geometries.
 Kathleen Schütz, Anna-Maria Placht, Birgit Paul, Sophie Brüggemeier, Michael Gelinsky and Anja Lode: Three-dimensional plotting of a cell-laden alginate/methylcellulose blend: towards biofabrication of tissue engineering constructs with clinically relevant dimensions, Journal of Tissue Engineering and Regenerative Medicine, Article first published online: 22 JUL 2015
Centre for Translational Bone, Joint and Soft Tissue Research
Technische Universität Dresden
Development of Bioinks for TE
Pneumatic extrusion allows printing of biocompatible materials in a wide viscosity range. However, the minimum feature size is somewhat larger than 100 µm due to the high fluidic resistance of pasty materials inside of narrow nozzles. Piezoelectric printing allows much finer drops but valve less dispensers are usually limited to an upper viscosity of about 10 mPa*s. Piezoelectric valve dispensers basically allow higher viscosities but apply high shear stress to embedded cells leading to a low viability rate.
The Fraunhofer-Institut für Grenzflächen- und Bioverfahrenstechnik is working on „bioinks“, that means printable material systems made from biomolecules of the extracellular matrix (ECM).
The developed material systems are based on water-soluble collagen. The chemical composition can be modified in order to adjust the viscosity in a range from 3….120 mPa*s. These bioinks are therefore printable even through valve less piezoelectric nozzles (Left: GeSiM micro dispenser with reservoir on top on a modified Nano-Plotter).
The variation of the matrix composition allows the adjustment of the following properties:
- Viscosity and gelling properties of the non-linked bioink
- Mechanical properties of the cross-linked hydrogels
- Composition and biological function of the cross-linked hydrogels (ECM)
 Eva Hoch, Thomas Hirth, Günter Tovar, Kirsten Borchers: Chemical tailoring of gelatin to adjust its chemical and physical properties for functional bioprinting. Journal of Materials Chemistry B 1, 41, 5675-5685 (2013).
 Eva Hoch, Christian Schuh, Thomas Hirth, Günter E. M. Tovar, Kirsten Borchers: Stiff gelatin hydrogels can be photo-chemically synthesized from low viscous gelatin solutions using molecularly functionalized gelatin with a high degree of methacrylation; Journal of Materials Science: Materials in Medicine 23, 11, 2607-2617 (2012).
 Sascha Engelhardt, Eva Hoch, Kirsten Borchers, Wolfdietrich Meyer, Hartmut Krüger, Günter E. M. Tovar and Arnold Gillner: Fabrication of 2D protein microstructures and 3D polymer-protein hybrid microstructures by two-photon polymerization. Biofabrication 3, 2, 025003 (2011)
Fraunhofer Institute for Interfacial Engineering and Biotechnology
Highly Customized and Affordable Implants by a new Hybrid 3D Printing Technology
FAST press release, January 29, 2016:
Eight European companies and research institutes have teamed up in the EU-funded research and innovation project “FAST”, which stands for “Functionally graded Additive Manufacturing (AM) Scaffolds by hybrid manufacturing”, to make a new 3D printing technology available for the manufacture of implants customized to the patient at affordable cost. Specific patient implants can promote effective preoperative planning, shortening the time of surgery and improving the lifetime of the implant.
Scaffolds production for tissue regeneration is one of the main fields where the “Design for Function” feature of AM makes the difference relative to the other production techniques, in particular if in the production process all the needed “functions” can be introduced: shape and porosity, mechanical stability and biochemical properties such as cell growth control or antibiotic function. The FAST project aims to develop a cost-efficient technology to integrate all these “functions” in a single AM process that is even capable to produce gradients in the bulk or surface properties of the individual scaffold.
Thus not only customized shapes of scaffolds can be produced, but also bulk and surface properties of the scaffold material can be tailored according to the specific needs of each individual patient.
In practice this will translate into improved tissue ingrowth and regeneration properties combined with higher structural stability of implants. Furthermore, the incorporation of smart fillers with bio-active properties into the scaffold material will reduce the risk of post-surgery infections. Thus, the FAST technology has the potential to increase the patients’ comfort at an affordable cost for them and the healthcare system. The project will demonstrate its developments in a small pilot production of scaffolds for bone regeneration to be tested in a pilot in vivo trial.
The FAST project is scheduled to run for four years from 1st December 2015 to 30th November 2019 with a budget of 4,9 MEUR, which is funded by the European Union under the H2020 Framework Programme for Research and Innovation.
FAST project partners:
- Abalonyx AS, Norway
- Fraunhofer Institute for Surface Engineering and Thin Films IST, Germany
- Fundacion Tecnalia Research & Innovation, Spain
- GeSiM Gesellschaft für Silizium-Mikrosysteme mbH, Germany
- Maastricht University, The Netherlands
- Nadir S. r. l., Italy
- Polyvation BV, The Netherlands
- Prolabin & Tefarm S. r. l., Italy
Press contact via the project coordinators:
- Dr. Lorenzo Moroni, Maastricht University, firstname.lastname@example.org
- Dr. Alessandro Patelli, Nadir S.r.l., email@example.com
Reconstruction of a Human Scaphoid Bone
The replacement of bones in course of accident treatment usually requires titanium implants. It is a widely used material for trauma surgery but shows inherent drawbacks: A mismatch of mechanical properties, interface issues to the surrounding soft tissues and no capability to grow.
A joint research project of GeSiM and Dresden University of Technology (TU Dresden) – Centre for Translational Bone, Joint and Soft Tissue Research – aimed in establishing 3D printing of patient-specific implants of a degradable biomaterial. As model the human scaphoid bone was selected and 3D data extracted from a CT scan.
In a first step the CT data of the patient were analysed to separate bones from the remaining tissue (Virtual environment/ contouring). Next the CT data was transformed into a 3D DICOM model using an Open Source software package. The scaphoid bone was isolated from the complete bone set to generate 3D STL data, a format describing surfaces by triangularization. The STL format is widely used by all kind of 3D printers, also the GeSiM BS3.1.
Finally the STL data of the scaphoid bone was loaded into the software of the GeSiM BS3.1. The bone model was printed from calcium phosphate bone cement VELOX® from InnoTERE GmbH, Radebeul.
This work is a research project without clinical background. Future research may be focusing on the settlement of osteoblasts or mesenchymal stem cells in the scaffold structure for subsequent incubation and generation of an artificial “living” bone.
We thank the BMWi for funding this work (AiF-ZIM program, project number KF2891602).
 T. Ahlfeld et al., Centre for Translational Bone, Joint and Soft Tissue Research, Technical University Dresden
 M. Heller, H.-K. Bauer, E. Goetze, M. Gielisch, I. T. Ozbolat, K. K. Moncal, E. Rizk, H. Seitz, M. Gelinsky, H. C. Schröder, X. H. Wang, W.E.G. Müller, B. Al-Nawas: Materials and Scaffolds in Medical 3D Printing and Bioprinting in the Context of Bone Regeneration. Int. J. Computerized Dent. 2016, 19, 301-321 (Figure 6)