Because our project is a fundamental one, there were a lot of teams that were interesting to collaborate with. For the next years we expect that by making an organized biofilm structure, a lot of teams can use the method we designed this year. During the development of our project, we received a lot of ideas and input from other teams - what is useful for a biofilm and what not. Some of these can be seen on the Policy and Practice page under iGEM Community section. For this we collaborated with the Berlin, KU Leuven and Amsterdam teams.

Moreover, we helped other teams by sharing the knowledge we have about biofilms and even printed a biofilm for another team. For sharing this knowledge we had several skype different teams, we helped with organizing different events where we talked to other teams, and we eventually went to Groningen to make a biofilm for them.

On the 17th of August together with team Groningen, we organised a Skype meeting to discuss the possibilities of a collaboration between us. The iGEM Groningen team are creating a biofilm that will be used to create energy out of salt and fresh water. Their plan is to create a selective biofilm that is placed as a barrier between the salt and fresh water, that causes a membrane potential difference. This membrane charge difference creates a current, which is called Blue Energy. But they had a couple of troubles with creating a stable biofilm containing their engineered selective bacteria. We believed that combining our projects could lead to a good result.

Our 3D-printer is able to print bacteria in a structured composition by printing with bacteria and alginate to form a gel. By using our 3D-printer to print their biofilms, we provide team Groningen a method to grow and develop the biofilm in the structure that is desired. The advantage for us is that we could be able to prove that our 3D-printer is suitable for other strains and bacteria. Therefore we traveled to Groningen from Delft on the 1st of september.

In Groningen we executed several experiments. By adding calcium chloride to the alginate, a gel forms with their bacteria encased. By using a plate filled with LB agar, the bacteria would be able to survive and create a biofilm.

The first experiment was printing with the bacteria in alginate in a certain structure. The team members of Groningen printed with their own bacteria, B.subtilis, in a form of their own choosing. The Groningen team prepared beforehand their own bioink (Sodium alginate+bacteria), calcium chloride and LB agar plates. Their plates did not require rhamnose as inducer, since their cells create biofilms by themselves.

They pasteurized 100mL of 1%(w/v) sodium alginate with appropriate antibiotic, and autoclaved 100mL of 0,1M calcium chloride to acquire sterile solutions. The LB agar plates were made using standard protocol. They had grown their bacteria overnight in 5mL LB with appropriate antibiotic. The overnight culture was then spun down, and the supernatant was discarded. The pellet was then resuspended in 100µL LB and mixed with 500µL sterile sodium alginate to make the bioink, and transferred into a 1mL syringe Before printing on the LB agar, 500µL calcium chloride was added to enable formation of the hydrogel.

The team then proceeded with printing with their self-made bioink. They were able to print on two agar plates, in the form of a house and a flower. They noted that the controls were not very user friendly, but after a few minutes they got the hang of it. In the end they agreed that our Biolinker was functioning as a 3D printer.

The second experiment, was measuring the selectivity of alginate. As mentioned above, the membrane should only let sodium ions (Na+) ions pass through to be a selective bio-membrane. Since the previous experiment proved that we were able to print the bacteria in the gel, we now wanted to print a biofilm made of alginate and see if it was selective. We drew a square on carrier material, on which we printed the alginate in “full color”. The alginate filter was then placed in a self-made voltmeter system, where the filter would separate the fresh from salt water. This separation of salt and fresh was not acquired. This was due to the salt water added on one side of the alginate filter, it leaked to the other side, which didn’t allow the possibility of adding fresh water. The voltmeter did measure a voltage of 10 mV, but the Groningen team stated that the this was caused by the carrier material, which produces a voltage of around 10-12 mV by itself. Therefore we could not conclude that our alginate filter is selective for sodium ions.

We stated that “our 3D-printer made out of K’NEX is able to print with our strains.”. We proved with the first experiment that the 3D-printer is an open platform that can be used for different strains of bacteria.

We would like to thank the iGEM Groningen team for their time, bacteria and for the great dinner we had afterwards.

On the 26th and 27th of March 2015 there were two training days for all the iGEM teams of the Netherlands. The teams invited were Groningen, TU Eindhoven, and TU Delft. Both days were filled with different lectures, on the 26^th at the University of Groningen, and on the 27^th at TU Delft.

We left the Delft station early in the morning, prepared for a long train ride. Without any delays we arrived in Groningen by 11am and were warmly welcomed with tea,coffee, and biscuits. Aljoscha Wahl started with a general introduction to iGEM, and we were introduced to the members of the other teams. It was really nice to meet them all and learn about all the different backgrounds. The first speaker was Renske van Raaphorst who gave a lecture about how to be successful in iGEM. She had participated in the iGEM competition in 2012 with the team of Groningen, and won the grand prize that year. She summarized what they had done and how their project had proceeded from beginning to end. It was very surprising how many obstacles they encountered and how they solved them. She gave us a few good tips how to approach problems and avoid stress moments. Clement Gallay continued with a general introduction about bio bricking. I thought that a lot of what she told was already known, since nearly everyone had a biology background. Yet it was a nice abstract about what we would be doing in the lab this summer.

Time flew by and at the beginning of the afternoon we got lunch in the canteen. It was a great moment to talk to the other team members and ask about their projects and experiences so far. After the lunch every team gave a short presentation about their project and their progression so far. That was a moment we could give comments and ask questions. Because we didn't have our final idea yet, it was a nice opportunity to hear different opinions about subjects we had in mind. Although the other teams were already a lot further than us, we are sure we can still catch up with them.

The day continued with a presentation by Anna Lauxen from the Groningen team 2014. She also gave us a lot of tips that were very practical. Maarten van den Nieuwenhof followed with an informative lecture about Human Practices in iGEM. Lastly Bayu Jayawardhana informed us about modeling in iGEM. He described the importance of modeling in Biology in general and the importance for iGEM. After the last presentation of the first day, we stayed a while to have dinner with the team of Groningen. They ordered large pizza’s with beer and we had a nice time with the other teams about the long, but educating day. We went home satisfied. On the way back we had a little bit of troubles, but thanks to the beautiful singing voice of Hector we were able to come home without extra costs.

On the second day, the iGEM courses were hosted at the TU Delft campus. Unfortunately due to disruptions with the trains, the Groningen team were unable to join the gathering. Luckily, the team of TU Eindhoven was able to come to with the other half of their group, so there were a lot of new faces for us, and many introductions. At 10.30 we started with a lecture by Anne Meyer about tuning and troubleshooting engineered genetic circuits. It also included many tips and tricks to avoid problems. Aljoscha Wahls followed up with a presentation about Network Motives, a kinetic perspective. Timon Idema started his presentation about physics and modeling behind the iGEM project, and how you had to ask the right questions to use modelling as a tool. He also gave information about how the judges evaluate the modeling tract. After taking up so much new knowledge, it was time for a lunch provided by the TU Delft.

After lunch Anne Meyer continued with a lecture about all the things the jury like and dislike in the iGEM competition. Since she had participated as a judge in the iGEM competition, she was able to gives a lot of useful information that we definitely would use. The last item on the agenda was a practical course in modelling, where we were given some exercises with matlab to see how modelling worked in practice. This gave a lot of insight for students who had never worked with matlab or modelling before. To close the two day lectures, everyone was invited for drinks afterwards in one of the popular bars.

All in all the two days were very informative, we got a lot of useful tips and tricks. Besides that we have a lot of fun. It was also very nice to meet the other teams and hear their project. We would like to thank all the participating teams, old iGEM members and lecturers for their time and energy in organizing and joining the educating and informative subjects.