Safety
Overview
This year, Team Tsinghua proposed a CRISPR/Cas9-based gene surveillance system and
attempted to realize such design in baking yeasts. Even though we have deliberately
chosen E. coli and S. cerevisiae as chassis organisms, of which biosafety levels are
well recognized and the protocol for experimental manipulation is well established, there
could have been unsolicited consequences if no attention for safe experiments is heeded.
Therefore, in order to minimize any unwanted accident, we have received proper training
and adopted several safety regulations in the laboratory as follows.
Lab safety training
First, before we started our project, all of our team members had received strict lab
safety training, including standard experimental protocols, proper disposal of biological
and chemical waste, information on hazardous chemicals and use of biosafety cabinets etc
from two senior members Liu Yan and Qin Yiran in Prof. Dai’s laboratory. Such guidance were
documented on the online portal in detail. Team members involved in wet works all went through
orientations with mentors or managers specifying proper equipment usage and safety before
gaining access to that lab.
Appropriate protection
Second, risks to team members brought about by potentially hazardous chemicals were minimized
by wearing appropriate personal protective equipments (PPEs) throughout lab time and
following lab safety regulations of Tsinghua University. Gloves, lab coats and close-toed
shoes are required when working with chassis organisms. Hazardous chemicals such as ethidium
bromide (EB) were carefully used and disposed according to protocols. No food or drink is
allowed in the working area.
chassis organism management
Third, E. coli strains that are used by our project (DH5α and BL21) as well as the yeast strain
are harmless and commonly accepted as safe organisms to work with. Our modified chassis
organism will be properly used and disposed according to the safety manual of the lab and
will not be released to the natural environment, a crucial principal of Prof Dai’s laboratory.
We amplified all plasmids to be used in yeast-related experiments in E. coli.
Safety in future
Fourth, in terms of future application, we also have a clear vision: we want to test our system
in yeasts as a proof-of-concept, and if such system is sensitive and safe enough, we want
to advance its application in mammalian cell lines. In the future, such system can be applied
in gene therapy to treat diseases like cancer with the help of viral vectors. Since we want to
combine the viral vector with our surveillance system, any potential risk that a viral vector
may bring in is worth consideration with scrutiny, such as unwanted genomic insertion of viral
vectors. Therefore, in order to achieve our goal, we will first test the efficacy and safety level
of the viral vector used in cell lines and then in mice. Also, we hope to introduce a well-controlled
molecular switch that only allows for bacterial and yeast growth in an artificial setting, therefore
to prevent any accidental release of the organisms we use.
