Human practices
12-May-2022 Dr. Hamm-Dubischar
The idea of our project is to help secure the supply of important consumables. To get useful information about the current status from people that are involved and affected by this, we contacted the Alfred-Wegener-Institut. They operate the Polarstern, which is a scientific icebreaker that often travels into arctic regions where there are often only few reliable supply routes. At the Alfred-Wegener-Institut Dr. Hamm, the head of Bio-inspired Lightweight Design & Functional Morphology / Sustainable Marine Bioeconomy, was kind enough to respond and help us get an idea of what criteria we need to meet in order for our project to be applicable in the real world. Dr. Hamm told us that our project is very interesting as they themselves are planning to use more biobased materials. Although their focus would not be using it on missions, but rather on bionic product innovation, which could open a new possible application method for our ink. Nonetheless, he was very forthcoming and told us a number of requirements that they think are necessary for them to be able to use our product as a material. The criteria he named were: suitable, as in little fluctuation in their properties, and reliable material properties, dependable accessibility in quantity that would make them usable on scales needed, processing possibilities, economic efficiency and sustainability.
These criteria helped us envision more clearly how our product should be and what kind of properties it has to possess for it to be actually used in real world applications.
07-Oct-2022 Prof. Dr. Lynn Rothschild
While meeting Dr. Lynn Rothschild, a well-renowned biologist associated with 3D printing working at NASA, the American National Aeronautics and Space Administration, we were told that “NASA loves the idea” of 3D printing. There are attempts to introduce 3D printing to space exploration. During the meeting, she provided us with many thought-provoking impulses, one of them being probably the most important aspect of the spirit of the age: why would we exchange established methods and fully functional concepts for our bioprinting approach, and where would their advantages lie, especially in comparison to products like plastics? Together we came up with new ideas of what she called “killer applications”. Taking into account the amounts of the main product, the synthesised cellulose, the rich uses of nano- and macrocellulose should be given consideration. Such could be applications in wound healing - furthermore improved by the effects of alginate - as well as making use of the printing process’ highest advantage: the precision in applications such as computer displays. We also talked about existing issues being the nitrogen supply for Azotobacter vinelandii and no gravity possibly causing a mess during the printing process. As we already came up with solutions, concepts and methods to test these, we were able to get some criticism on our test procedures. If we were able to improve the 3D printed products’ traits not only by adding existing resources like regolith that’s found on the moon for higher stability and rigid structure, but moreover by adjusting the structure itself like bone’s hierarchical structure, for what 3D printing is very convenient, without a doubt we could state that 3D printing is the next step of technological progress.
11-Oct-2022 Ellen Oldenburg
We wanted to talk to someone who was on an expedition located in an environment like the one we built our Bioprinter for. Therefore, we asked Ellen Oldenburg, a PhD student at the institute for quantitative and theoretical biology of the Heinrich-Heine University Düsseldorf, to have a talk with us. She went on the 2019 MOSAiC Expedition onboard the Polarstern, so she was one of the most befitting contact persons to assess our project’s relevance. We asked her whether it would be of help on expeditions. She told us that there are always unexpected situations, which suddenly need a small replacement part or something like a clamp to better hold equipment in place to make sure it does not get broken or to fix it. For this reason, it would be useful to know the printable mass and how long that would take to print and harden. Something that we should be able to estimate with the help of our model and with the data gathered from our experiments.
Online meeting with Ellen Oldenburg and our members Timo and Jona
Integrated human practices
In order to create our bioink for 3D bioprinting in space, we first had to search for suitable bacteria to create a 3D Bioprinter that works in space and is capable of producing several different products for almost every situation that could arise. For this, we searched for suitable bacteria that already produce alginate such that we only need to overexpress this and how to combine it with a more stable material to make it harden.
23-April-2022 Leo Chi U Seak
In April, we decided on the bacteria we wanted to work with. Azotobacter vinelandii was our bacterium of choice. Since A. vinelandii is not as well established in iGEM as other organisms, we had to do more research to work with it appropriately. That is why we contacted Leo Chi U Seak. He is a PhD student at the University of Cambridge and has experience in working with A. vinelandii. We contacted him, shortly introduced our project to him and asked for his help regarding why they used nifH promoters and how to properly transform A. vinelandii. He was very friendly and eager to help us and sent us protocols that he kindly received from Prof. Dennis R. Dean from Virginia Tech University while working on his own iGEM project in 2014. We were told that the nifH promoter is a strong promoter for A. vinelandii. Furthermore, he recommended we could use a lac promoter and compare those two promoters with each other. This was exactly what we needed to overexpress the alg8 gene to produce more alginate in A. vinelandii. In addition, he told us that we should consider that different mediums and conditions can greatly influence the production of alginate and cellulose. We had in mind to try this out later on in our project when we used different mediums.
24-April-2022 Professor Dr. Einsle
We asked Professor Dr. Einsle for help shortly after getting help from Leo Chi U Seak. He gave us a lot of feedback on alginate and how it is already used in many ways such as molecular cooking or in biomedical applications. This helped us to get a better perspective of the properties of alginate and what it can be used for. It may not be the strongest material, but it has other properties such as elasticity which would help in creating a material that is more resilient in the face of external stress as it could help create a material which is not brittle1. We thought we could use this elasticity to create objects that often need to deform and then reform. An example of this would be earplugs or menstruation cups. He told us that if we wanted to polymerize alginate, we could use divalent cations to harden it and give it similar properties of bubble tea pearls. Additionally, he told us that the length of the oligosaccharides of the sugars could influence the properties of the material later on. For that, we then looked deeper into this and found out that alginate with a higher α-l-guluronic acid content than β-d-mannuronic acid have a higher mechanical stiffness and strength2. Professor Einsle also told us that the methods developed by Dennis R. Dean of Virginia Tech University are well established and, while a bit more laborious than just working with Escherichia coli, they use it routinely. He told us that they are using the arabinose promoter in their work. We adopted this as there is no endogen T7 promoter for A. vinelandii and we came to the conclusion that this was our best option as a a stong promotor for our microorganism.
14-Jul-2022 Dr. Markus Braun
Dr. Braun is the head of space life sciences program at the DLR, which is the German centre for aviation and space travel. He gave us a lot of valuable feedback for our project and lots of ideas where we could take our project in the future. First of all, Dr. Braun told us that the European Space Agency (ESA) wishes to construct a platform which helps bridge the gap between the constant necessity for resources and the harsh environment around the International Space Station. Furthermore, the printing process and our microorganisms do not seem to be negatively affected by the microgravity on the moon. The printing process might actually be benefitted by the microgravity, as it could improve the crosslinking of the polymers. In order to test the printing in microgravity, he suggested us to print upside down, which we then proceeded to do for our proof of concept We were also told that it would not make much difference whether we wanted to work on the moon or not, as gravitational limits are negligible. In an extraterrestrial environment, a completely closed system is required to prevent microorganisms, such as bacteria, from escaping and requiring costly decontamination or even endangering the health of the astronauts.
Another thing we need to keep in mind is that to reduce weight everything should be dehydrated, so we would need a dry premix of our medium and dehydrated cells. The premix has to be a minimal medium. For new cultures, it would also be necessary to establish a way to restock on cultures through different means like using cryostocks or batch cultures. We were also told to check how much energy and resources are needed for printing. He gave us the idea that we could use our printer to print things like handkerchiefs or soil for plants.
27-Aug-2022 Prof. Dr.-Ing. Jochen Schmid
Prof. Dr.-Ing. Jochen Schmid is a professor for microbiology at the TU Münster at the institute for molecular microbiology and biotechnology. We met him at the JuniorJam and began talking about our project. Professor Schmid helped us think more in depth about the production of alginate and cellulose and how it can be influenced through many different means. One of his questions that helped us rethink how we should approach the alginate and cellulose production was if A. vinelandii uses the same precursor for both, alginate and cellulose, could there be a conflict in how much is allocated to which metabolic pathway3. This could potentially hinder the production of either of the components which are critical in our bioink. Furthermore, we were asked if we checked how the oxygen concentration impacts the initiation of the metabolic pathway of A. vinelandii. And last but not least, he mentioned how the oxygen concentration could potentially influence the β-D-mannuronate (M) and α-L-guluronate (G) residues and how they bind to each other. He said that a higher oxygen concentration could potentially make them more stable and therefore is more suitable for our bioink. This is connected to how A. vinelandii protects its nitrogenase from oxygen by enveloping the cell in a capsule made out of alginate, inhibiting the diffusion of oxygen3.
Dr. St. Elmo Wilken
Dr. St. Elmo Wilken is a Postdoc at the institute for quantitative and theoretical biology. He helped us to understand how we could use and improve an existing metabolic model of Escherichia coli as a base for a rudimentary metabolic flux analysis of A. vinelandii. Additionally, he told us which tests we should conduct in order to gather the necessary data to create the model and helped us with finding the protocol for the alginate measurements. For the model we wanted to measure the alginate production, the sucrose intake and the growth of our A. vinelandii strain.
- Haimei Zhang, 2 - The Basic Properties of Building Materials, In Woodhead Publishing Series in Civil and Structural Engineering, Building Materials in Civil Engineering, Woodhead Publishing,2011, Pages 7-423, https://doi.org/10.1533/9781845699567.7, https://www.sciencedirect.com/science/article/pii/B9781845699550500025
- Georgia Kaklamani, et al. Mechanical properties of alginate hydrogels manufactured using external gelation, Journal of the Mechanical Behavior of Biomedical Materials, Volume 36, 2014, Pages 135-142, https://doi.org/10.1016/j.jmbbm.2014.04.013, https://www.sciencedirect.com/science/article/pii/S1751616114001222
- Urtuvia, V., Maturana, N., Acevedo, F. et al. Bacterial alginate production: an overview of its biosynthesis and potential industrial production. World J Microbiol Biotechnol 33, 198 (2017).
https://doi.org/10.1007/s11274-017-2363-x