Q: What risks does your project have in the laboratory stage? What actions have you taken to reduce the risks?
A: Our experiments were done at the S1 or S2 risk level, which means that the materials used in our experiments were not known to have serious negative impact on human health. Nevertheless, in order to reduce the risk to the lowest conceivable level, we also used all the necessary protections, including wearing rubber gloves and special experimental clothes. Furthermore, we always had advisors or instructors nearby so that we can call for help if anything goes wrong.
Q: Are your teammates qualified for these experiments and able to ensure their safety?
A: Yes. All the team members received trainings prior to the experiments, including background introduction and information on potential risks, and have rehearsed all standard procedures beforehand. Our advisor Xuan Wang, who is a previous iGEM participant, gave us about ten classes introducing the definitions and basic procedures of biological engineering, the normal steps and schedule of the iGEM competition, previous teams’ designs and outcomes, and a brief background on the ideas about our project. During all the experiments he was always accessible to ask about experimental steps, for suggestions, or for help. Before the first time we did each experiment, he gave us notices about potential risks and things we should care about, and sometimes refreshed our knowledge of the standard steps when we made mistakes. Some of us had attended the Gene Engineering course, taught by Chuan Ni, before the iGEM competition, which includes extra basic training and rehearsing.
Q: Do you think your current design is sufficient to ensure safe and ethical practice?
A: We still need some further improvements. Our current design includes inflammation detection and the reporting of results, but the bacteria left in the intestinal system or in the environment might influence the pre-existing balance. Thus, we still need to find some way to kill the engineered E. coli after the journey is finished and the results are obtained. Generally, we have two ways of solving this problem. First, DNase can be used to destroy the engineered bacteria’s genes. We are planning to use a weak promoter for the DNase gene, so that the DNase gene is expressed slowly throughout the process. After modifying the bacteria and doing plenty of experiments, we want to keep the time until complete destruction of the bacteria’s DNA between 14 to 24 hours. Secondly, all the engineered bacteria (like Top 10 and DH5 alpha) are leucine auxorophs , which means that they cannot live without leucine for long, so that using these bacteria is intrinsically safe. If we are going to use Nissle 1917 instead, we will make them leucine-auxotrophic too before letting them enter the patients’ gastrointestinal system.
Q: Who has your team worked with in solving uncertainties or gaps in ensuring your project’s safety? Are they difficult to contact?
A: We worked with instructors and advisors who gave us lots of suggestions and helped us a lot in ensuring our project’s safety, as well as filling gaps in the process of designing and planning. They were easy to contact through WeChat, text messages, phone calls, and, most of the time, face to face. There were also others that we