Difference between revisions of "Team:RDFZ-China/Design"

What are we facing?

Biosafety has always been the major concern to the public, to the companies and the researchers. Doubts and worries raised just as genetic technology was invented. With the rapidly growing of synthetic biology and iGEM community, more and more synthetic biology products are built with the widely distributed DNA toolkits or the inexpensive DNA synthesis service; we are facing unprecedented biosafety issue that unwanted leakage of synthetic biology products to the environment may cause an unexpected but definitely disastrous problem.

Predecessors

For decades, researchers were striving to build biosafety devices through auxotrophy or external inducive kill switches[], holins and restriction enzymes are most commonly used. Most of the failures of the previous devices were caused by mutation and evolution of immune.

The two major threats of engineered microbes’ leakage are the possible Horizontal Gene Transfer which will lead to the spread of recombinant DNA to the entire ecosystem, or the engineered bacteria could contaminate or overrun the natural habitat.[]

Project Xscape

Under this circumstance, this year we decided to be a fundamentalist to synthetic biology, by using genetic circuits and logic gates, to establish biosafety devices which can apply to the real-world situation.

Since cell death and lysis mean there is a continual presence of free DNA in the environment, holins, which are most widely used are excluded from our choices, and colicin E2 nucleases (Darmstadt iGEM2016) came into our site. We choose site non-specific nucleases since the entire genome and plasmids needed to be entirely digested to prevent the spread, and we use nucleases from a different family to prevent the possible evolution of nuclease inhibitors. Artificial DNA, RNA, and amino acids are a good solution, but due to its high cost so far, it is not applicable to most of the user.

For fermentation

The first device we build is for the fermentation; we want to execute the escaped engineered bacteria from the fermenter, accidentally or intentionally. We used two environment factors to monitor the bacteria’s situation: temperature and population density, they are both high and tunable in the fermenter. So, the device will initiate when temperature and density are both low. We used thermal sensitive regulator (NUS iGEM2017) and quorum sensing regulator (MIT iGEM2004)as our sensor, sRNA and tetR family repressor PhlF(Glasgow iGEM2015) as the signal inverter. We add intergrase (Peking iGEM2017) controlled by the thermal sensitive regulator, which will turn the promoter of a lethal gene when temperature rise in the fermenter so that bacteria can survive at the very beginning. Also, we build a model to stimulate the minimum autoinducer required at the beginning of the fermentation[Modelling], same as the purpose of integrase. This model is for keeping bacteria alive at the very beginning of fermentation. Together they form a NOR gate which will lead to cell death through genome degradation when temperature and density decrease.

For Therapy

The second device we build is for therapeutic bacteria, the device can carry out noninvasive tracing through ultrasound imaging of the gas vesicle, release the drug (from SHSBNU 2017) controlled by a thermal sensitive regulator at nidus by ultrasound tissue heating, and heat to a higher temperature to release nuclease and kill the bacteria after it finishes its mission.

For Metabolic Stress

We applied capacity monitor [] to quantify the expression burden of all our systems, and to reduce the metabolic stress, we designed another device for fermentation which used a LuxR repressive promoter (Peking iGEM2011) and cold-regulated 5’UTR region (Ionis Paris 2017). This device only involves one transcriptional regulator, which will be less energy consuming.

DIY bio and Biosafey

Back to the growing and glowing synthetic biology community, despite the ones doing it on campus, more and more people are starting it at home, they call themselves Genehacker or DIY biologists. The lack of sufficient training and efficient surveillance will be a time bomb which we do know there will be a monstrous harmful bioproduct will be made someday in the future, and indeed, it will be a significant threat to the current biosafety basis. Recall our memory to iGEM2009, Peking surveyed DIY bio, almost ten years later, we conducted a similar DIY bio-survey again. We tried to order materials for molecular experiments, using the delivery address to our home, the result was quite shocking that we can buy almost everything for the molecular experiment, from the internet. Then, we went through relevant laws and regulations throughout the world, which we found out that there are no laws related to the credit certification and the address certification about the people who book the biology reagent. Most of the laws are about the quality certification and how they would serve the user after they bought this. We interviewed the Director of the center for disease control and prevention. He said that within his experiment with the disease caused by the Bacteria leak, environmental pollution, the vast impact had been caused. Our country has been making all effort which is the highest effort that we have made in the history. He said it is not easy to solve the problem with hard work, it needs the cooperation between all the countries. He made an example of 731 army during the second world war two, the outbreak of pathogens can cause significant social harm. We are still on our way to win the battle, but the effort still needs to be put in.

Community and Future

Also, we hosted two major meeting in Beijing, a Biosafety Forum in October, we invited team leader who runs his high school lab, lab teacher from a university lab, and a former team member from Peking iGEM2009, who participated in that DIY bio investigation ten years ago.

We concluded that the development of DIY bio should be taken seriously, and the permanent way to solve it is through implanting Biosafety awareness into our academic culture. Also, as iGEMer, we should strive to be the considerable and responsible leaders in our community, to ensure the biosafety issue has been taken properly. Another meeting was with biology Olympians all around China, we discussed the future of biology community during the meeting, especially with more and more high school iGEM teams coming up in China, but lack of relevant instruction and education to the students. We came up with the idea of setting up a collaboration between school to share and overcome difficulties hand in hand. This kind of meeting will be continued after iGEM2018, since the community usually grows fast after every iGEM season.

Hopefully, years later, biosafety awareness and considerations can be seriously taken in communities, laboratory studies, and real-world applications.