Safety in wet lab
XJTLU requests all iGEM team members to pass the lab safety quiz before entering the research lab. Besides, iGEM students understood the risk in handling the HEK cell line culture and the operation principles of every machine we used. Our helpful professor team support us with their expert knowledge, especially when we facing some complex and unfamiliar experiments.
|
Protections |
Details |
|---|---|
|
Lab coat |
To protect our skin and clothing especially when we are handling dangerous liquids. |
|
Gloves |
Gloves are required for every experiment. But all students need to make sure they have taken off the gloves before getting out of the lab. DO NOT touch any door handle with gloves. |
|
Requirements on clothing in the lab |
No slippers and short pants in the lab, and hairs need to be tied. |
|
Bleach |
We use HEK293T, a wildly used human cancer cell, to produce exosomes. Therefore, every container (flask, dish, waste bin, tips, etc.) that have contacted with HEK cells is teated with bleach before disposal. |
|
Hand-washing |
To make sure there is no contamination on our hands, we must wash our hands before leaving. |
|
Alcohol disinfection |
To prevent our superclean bench from contamination with bacteria, we use alcohol to disinfect our hands and equipment in every experiment before entering the superclean bench. |
|
Disposal |
In our lab, bins with different colors indicate different ways of disposal. We throw ordinary trash into the blue bin, bio-risky materials into the yellow bin. Besides, used ice is directly melted in the sink. |
Safety related to the choice of chassis
Since our ExoCar project is aimed to treat neurodegenerative diseases by injection of exosomes, choosing a suitable and non-pathogenic chassis is crucial. Therefore, we use DH5α competent cells and the pcDNA3.1(+) vector for transformation. Competent DH5α cells are prepared by ourselves, by using ice-cold CaCl2 as chemical reagent. The plasmid pcDNA3.1(+) is purified from cultured bacteria. All materials used in these processes are in line with the iGEM reagents and chassis whitelist.
Ethics and safety in medical RNA molecules
When comes to gene-based medicine, there are always doubts regarding ethical issues and the safety issues in usage. Based on the judgement from Ethics Committee of Suzhou Municipal Hospital, there are no obvious ethical risks in our project. Admittedly, there is no one hundred percent guarantee that the exosome drug will never cause any side effects. Nevertheless, one thing for sure is that this medicine can achieve precision medicine, meaning that the gene encodes for a therapeutic protein is gained from the patients’ body themselves. Therefore, the rejection of exosome drugs by the patients' body may be alleviated.
Safer drug
- Higher specificity
Although the exosome-based drug utilizing EAAT2, the RNA codes for excitatory amino acid transporter 2, this drug has been proved genetically risk-free. This exosome drug has high fertility and specificity, since the Cx43 semi-channel displayed on exosomes can specifically recognize and fuse with cells expressing the same channel proteins.
- Easier degradation
In human body, exosomes can be degraded automatically within 20 minutes, and the average time is 5 minutes. Such a short half-life does not allow exogenic RNA to incorporate into human DNA, so the sequence of the DNA can remain stable. Moreover, the rapid elimination of the exosome drug in the human body can also prevent the neurological insensitivity caused by overproduction of EAAT2 protein.
XJTLU lab safety related materials
1. For every new user of the research and teaching laboratories of the Department of Biological Sciences, we have to watch a video on the Biosafety Induction made by the Biosafety Officer and pass an MCQ quiz on biosafety before we are qualified to work in the lab and use any equipment in the department.
2. Health and Safety Agreement Form is a form that every user of the laboratory in the Department of Biological Sciences has to be signed immediately after receiving the safety lecture. The signing of this form by us indicates that we understand our obligations and agreement to perform lab work according to the standard operation procedure of the BIO department.
3. The Supervisor Confirmation Letter is signed by every supervisor and his/her students. In this form, students need to provide their personal information and supervisors have to ensure students’ safety in the lab.
4. Dr. Sung Kay Chiu is our PI as well as biological safety officer, and we can contact him continuously when we encounter safety related issues.
Prospective
In our ExoCar project, we use HEK293T cells as the exosome producing cells. However, even if some people have done in vivo experiments on HEK293T exosomes, saying that it will not cause such results.In actual clinical treatment, MSC (bone marrow mesenchymal stem cells) can be used instead of HEK293T for exosome production to prevent other components in the cytoplasm of cancer-like cell lines from affecting the target cells.
References
J.M. Gudbergsson, et al. (2019) ‘Systematic review of targeted extracellular vesicles for drug delivery – Considerations on methodological and biological heterogeneity’, Journal of Controlled Release , pp. 108–120. [Online]. Available from: https://doi.org/10.1016/j.jconrel.2019.06.006 (Accessed: 22 Oct 2019).
