Before the experiment, all members of our team received online training in biosafety under the guidance of Dr. Nie. In order to reduce the possibility of experimental errors, it is important to ensure the safety of the experimental process. For the particularity of our experiment, we have learned basic knowledge of biochemical and genetic engineering; basic information about DNA, RNA, protein, and DNA plasmid; application of pipettor, centrifuge, polymerase chain reaction (PCR), etc. Our experiment is performed in the molecular biology laboratory of the Experimental Research center of China Academy of the Chinese Medical Sciences, a BSL-2 laboratory. The laboratory not only meets the requirements of BSL-1 laboratories but also is safer and has effective prevention and treatment measures for pathogenic factors with moderate or potential hazards, for instance, fire extinguishers, eye washers, and other facilities, as well as the corresponding clear instructions.

1. Wear work clothes when entering the laboratory, and wear corresponding gloves and protective equipment when doing experiments.

2. It is forbidden to drink or eat in the laboratory. Don't bring food utensils into the laboratory to prevent poison pollution. Don't eat chemicals. Wash your hands before leaving the laboratory and eating.

3. Use volatile chemicals and drugs in the fume hood.

4. In the treatment of laboratory waste liquid, attention should be paid to classification and timely treatment. A large amount of waste liquid cannot be stored at the same time, and the waste liquid should be prevented from mixing.

5. When using the medicine, everyone should use it under the instruction of the coach. During the test, the range should not be too large, causing the liquid to splash and spray, so that it can be thrown onto himself or others.

6. Do not touch chemicals and chemical instruments without personnel.

Basic operation processes：
The use of pipettor:
1. Set the pipetting volume: the normal adjustment method is to adjust from a large range to a small range, and rotate the scale counterclockwise. When adjusting from small range to large range, it should be adjusted to exceed the set volume scale first, and then back to the set volume, so as to ensure the accuracy of the pipette.
2. Assemble the liquid transfer gun head: insert the liquid transfer gun vertically into the suction head, rotate it half a turn left and right, and tighten it.
(Attention: the method of hitting the suction head with the pipette is undesirable. The long-term operation will cause the parts of the pipette to loosen because of impact, which will cause the knob for adjusting the scale to get stuck.)
3. Suction and discharge of liquid:
Vertical aspiration:
The tip of the suction head is immersed below 3mm into the liquid level, and the pipettor head is pre-moistened and washed in the liquid for 2 ~ 3 times before sucting to ensure the accuracy and precision of liquid transfer;
（Attention: slow suction and slow release of the liquid.)
4. The liquid transfer pipettor with liquid suction should not be placed horizontally.
5. The scale of the pipettor should be adjusted to the maximum after each test.
6. Do not use a large range pipettor to transfer a small volume of liquid.

All strains, reagents, and consumables we used in the experiment are safe, do no harm to the ecological environment, and do not cause any harm to our human body under the standard operation of our laboratory personnel.

- We did not use any animal or human genes in our experiments.
- All gene editing techniques used in our research are for the purpose of scientific experimental research.

Trapotsis, Arthur. “Biosafety Levels 1, 2, 3 & 4: What's The Difference?” Consolidated Sterilizer Systems, 1 Apr. 2020, https://consteril.com/biosafety-levels-difference/.