Safety
Biosafety
Our project aims to design an enclosed filtering device containing
engineered bacteria with an enhanced ability to reduce phosphate in water
bodies. We have fully considered the risks of our product’s implementation
and ensured the biosafety in vivo and in the environment.
In vivo Biosafety
To decrease phosphate levels in bodies of water, we engineered the both
DH5α and BL21 (DE3) competent E. coli. It is not considered hazardous by
the 2012 OSHA Hazard Communication Standard.
Environmental Biosafety
To prevent accidentally leaking bacteria into the environment and
increasing the risk of environmental hazards, we introduce a biosafety
system different from the commonly used kill switch. The system includes
the following three designs:
-
Bacteria Filter for Leakage Prevention
Having been taken into consideration that the average diameter of an
E. coli is about 1 to 2 micrometers, filters on both sides of the
device use filter paper with a pore size of 0.45 micrometers to
prevent the leakage of the engineered bacteria into the natural
environment. For further information on the design of the
implementation device, please visit our
Hardware page
.
-
Bacteria Natural Growth Inhibition by Polyphosphate Accumulation
Without any killing mechanism, engineered bacteria would naturally
grow and reproduce in the filtering device. However, after bacteria
can absorb more than 20mM of phosphate, their growth cycle would be
disturbed (Rao). As the bacteria in the device are engineered to over
absorb and fixate phosphate and the overaccumulation of polyphosphate
results in natural growth inhibition, environmental hazards could be
naturally inhibited. Even if the filter paper was accidentally broken
by any natural object, the concern regarding pollution by bacteria
leakage is little because the bacteria’s growth and reproduction would
be naturally inhibited in less than 24 hours.
-
Monitoring Polyphosphate Accumulation Biosensor
The design of the polyP sensor plasmid includes genes encoding for
polyphosphate-sensitive sigma factor and mCherry fluorescent protein.
Expression of mCherry decreases followed by polyphosphate accumulation
in the bacteria. As the hardware detects reduced fluorescence levels
to the minimum, an alert is sent through the software to notify the
users to replace the filter in time, thus avoiding the lysis of the
bacteria cells after bacteria death releasing phosphate and other
genetic materials into the environment. For more information on the
design and engineering of the polyP sensor, please visit our
Engineering Success page
. For more information on the light-sensing chips of the hardware and
alarm system of the software, please visit the
Hardware page
and the
Software page
, respectively.
Our project introduces a combination system to solve the problem. What’s
more, we consider this system to compete with the other systems broadly
adapted in iGEM. For example, many iGEM teams today select kill switch
systems to reach environmental biosafety. A normal kill switch could
experience leaky expression or malfunction of the gene, causing
over-killing or under-killing of the engineered bacteria. In addition,
expressing the kill switch is a waste of energy for the engineered
bacteria. The mechanism of a kill switch causes the bacteria to produce
poison and antidote (iGEM Pasteur_Paris) at all times just to stay alive.
A lot of energy and materials would be consumed during the production
process, which lowers the efficiency of bacteria functions. However, by
limiting the bacteria inside the hardware container, naturally inhibiting
bacteria growth, and expressing biosensors, our biosafety system allows us
to ensure biosafety while maintaining the efficiency of the bacteria
functions. Accordingly, we hold that our system is a potential system, and
we recommend the former iGEMer could take it into consideration and make
more exploration.
Laboratory Safety
All lab members wear gloves, lab coats, and safety goggles at all times.
The lab is also equipped with emergency showers, eye washes, ventilators,
fire blankets, and first aid kits. Dangerous experiments, if any, will be
performed under supervision. The lab is classified as P1 (Protection
level), where no substances that cause adverse effects on the human body
will be used. This team follows the safety protocol provided by iGEM, as
well as the National Yang-Ming University's Center of Environmental
Protection and Safety and Health guidelines (
https://ces.nycu.edu.tw/files/11-1151-89-1.php
,
https://ces.nycu.edu.tw/files/11-1151-2320.php
Human Practice Safety
During interviews and collaborations, participants must have their
vaccination or exception on record. All participants are required to have
an increased level of COVID-19 testing, masking, and quarantine
procedures. If the confirmed cases surge, we will use virtual events to
replace in-person meetings to prevent the spread of pandemics.
References
Correlates of smallest sizes for microorganisms - NCBI bookshelf. (n.d.).
Retrieved September 17, 2022, from
https://www.ncbi.nlm.nih.gov/books/NBK224751/
How safe is safe enough: Towards best pratices of synthetic biology.
OpenWetWare. (n.d.). Retrieved September 22, 2022, from
https://openwetware.org/wiki/
How_safe_is_safe_enough:_towards_best_pratices_of_synthetic_biology
Rao, N. N., Liu, S., & Kornberg, A. (1998, April). Inorganic polyphosphate
in escherichia coli: The phosphate regulon and the stringent response.
Journal of bacteriology. Retrieved September 17, 2022, from
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC107147/\
Team:pasteur Paris/kill. (n.d.). Retrieved September 25, 2022, from
https://2018.igem.org/Team:Pasteur_Paris/Kill
