Street science is an event organized by Bielefeld Marketing which takes place three times a year in downtown Bielefeld. The aim of this event is to communicate science to the public.

We participated in this event on April 4^th 2015, a Sunday open for business, from 12 am till 6 pm. It was the first time we presented our topic and team in the public. Therefore, we had created posters about synthetic biology, the iGEM competition and our topic. As it was very crowded, we got into conversation with many people and informed them about problems with drinking water and what we want to do about the problems.

We also explained what synthetic biology is and where you can find products from genetically engineered organisms in everyday life. To evoke enthusiasm for science in children, we offered several small experiments. The most popular experiment was the DNA isolation. With simple household objects like salt, rubbing alcohol and dish detergents, children could extract DNA out of fruits such as bananas and kiwis. Of course, parents and we supervised them in experimenting. For younger children we offered chromatography with filter paper and creating ink images by pipetting ink onto sugar cubes in water. As a gift, we sent them the images and let them take the chromatograms. For adults, we had prepared a set of memory cards with images of products and the corresponding production organism to show them where they are in contact with biotechnological products in their everyday life. As genetic engineering is a controversial issue in Germany, we tried to lower concerns by outlining the facts about this topic in a small presentation. As a highlight, we created a chemical garden every two hours by adding metal salts to a solution of sodium silicate. By doing so, the salt seem to grow in form of plants.

As we had already decided to focus on water analytics at that time, we did a survey to find out which water contaminants are most important to people and which requirements they have regarding a biosensor. More than 60 people filled out our questionnaire. Although the results are obviously not representative, they were an interesting insight and helped us in defining in which direction we wanted to go with our project.

Survey

From the beginning on it was very important to us to develop a biosensor that can be used outside the lab. Therefore, we asked which requirements people have with regard to such a sensor. The results showed us that our biosensor needs to be simple, cheap and reliable.

When it came to concerns regarding whole-cell biosensors, people were divided approximately fifty-fifty. However, many people would use them despite their apprehension.

Biosensors without live cells were viewed more positively. This confirmed us in developing cell-free biosensors.

Most people will only use a biosensor if it is very fast. We believe that cell-free approaches can be superior in this respect.

Every fourth respondent said they did not know enough about synthetic biology to form an opinion. We hope that by providing information and taking science out of the lab, we were able to contribute to a positive reputation of synthetic biology.

Conclusion

All in all, it was a successful day. We were able to fascinate children for science and informed people about our project, which was received very well. The survey showed us that heavy metals are a suitable target for our biosensors. Some requirements for biosensors like ease of use, low cost and reliability were brought up very frequently, and we tried to bear them in mind when designing our biosensors. Most respondents would use biosensors as long as they are fast and cell-free. This confirmed us in developing cell-free systems.