MATERIALS
has developed a gel bio-ink for use in 3D printed human tissues2
that may
prove to be a game-changer. During the course of their research, the UBC team analysed three different gelatin methacrylate (GeIMA) hydrogels,and found that a hydrogel made from cold-soluble gelatin was the best performer and therefore a strong candidate as a bio-ink for future organ printing. It could form healthy tissue
scaffolds, allowing cells to adhere to it and grow successfully, and remain stable at room temperature. This last benefit is particularly significant, according to Keekyoung Kim, an assistant professor at UBC Okanagan’s School of Engineering: ‘A big drawback of conventional hydrogel is its thermal instability. Even small changes in temperature cause significant changes in its viscosity or thickness. This makes it problematic for many room temperature bio-fabrication systems… which must generate products that are as uniform as possible if they are to function properly.’ There are hopes that this bio- ink will not only help researchers to create artificial organs but also lead to the development of better drugs, tissue engineering and regenerative therapies. ‘The next
With regard to the wider world, we are already seeing “organ- on-chip” models to test and develop new pharmaceutics and reduce animal testing. The next phase will be 3D bio-printing real tissue for personalised medicine’
Adam Perriman University of Bristol
step is to investigate whether or not cold-soluble GeIMA-based tissue scaffolds can be used long-term in both the laboratory and real-world transplants.’ Elsewhere, in the US, a Chicago
crowd-funded bio-printing start-up, Biolife4D, has set a goal of 3D printing entire human hearts for transplants. It is working to develop replacement hearts by converting patients’ own blood cells to specialised heart cells that would be used to make bio-ink. After it is printed, the heart would be transferred to a bioreactor to mature and grow stronger, enabling the cells to survive the bio-printing process.
Complex 3D metallic structures can now be printed with a new class of inks using a range of metals, alloys, oxides and other compounds – and even rust
As yet, however, the company is remaining quiet on how close it is to developing its first viable heart. Printing human stem cells,
meanwhile, is yet another area generating enormous excitement in AM circles. A team from the University of Southampton in the UK and the Technische Universitat Dresden in Germany has been working with Laponite, a synthetic nanosilicate clay material, to create a 3D printable bio- ink for making human mesenchymal stem cell structures, with particular implications for skeletal applications.3 The new bio-ink is made from a
combination of Laponite, alginate and methylcellulose. Laponite is used as a filler or thickener in the cosmetics industry, and its shear- thinning properties offer an improved level of printability. Usefully, its viscosity also decreases when force is applied, which means it can be easily extruded, and once the force from the extruder is removed the printed material will stay in the required shape. Results from incubation tests
showed that the 3D bio-printed scaffold made from the Laponite material allowed for a high level of cell viability, with 70–75% cell viability maintained after the 21-day culture period. Compared with the bio-inks
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