Non-pathogenic strains of E. coli K-12 strains BL21 and dH5α from Life Technologies were used for bacterial cloning of plasmids and expression of proteins of interest. These strains are Risk group 1 and were handled in a BSL2 Biosafety cabinet. The E. coli strain carrying the Biobrick BBaK299812 (containing parts derived from Risk group 2 organisms) was handled as a Risk Group 2 agent. Mammalian cell line HepG2 is classified under Risk group 2, and was also cultured in a BSL2 Biosafety cabinet.

In our project, we aim to engineer non-pathogenic E. coli as a vector to deliver a potential drug into the tumour core. We use the Biobricks Part BBa_K299812, which contains the invasin gene from Yersinia pseudotuberculosis and the listerolysin O gene from Listeria monocytogenes. The Invasin protein allows for bacteria to enter mammalian cells, while Listerolysin O is a pore-forming protein that enable bacteria to escape the endosome. These two proteins are involved in pathogenesis of their respective bacterial species.

The Invasin and Listerolysin proteins enable our E. coli to enter mammalian cells, and escape the endosome, where they can subsequently deliver an encoded therapeutic to kill the tumour cell. To ensure that these proteins are only expressed under the conditions of the tumour microenvironment, the invasin and listerolysin proteins will be placed under the control of an anaerobic promoter, and a quorum sensing system.

All our team members have undergone Chemical, Biological and Fire Safety Training from the Office of Safety, Health and Environment (OSHE) , the department in charge of Laboratory and Work Safety at the National University of Singapore.

For each protocol used for our experiments, we have a separate risk assessment. Please refer to our ‘protocols’ page for more information.

Our laboratory is equipped with biological and chemical spill kits, and all members of our iGEM Team are trained to handle Biological and Chemical Spills. Our laboratory is classified as Biosafety Level 2, according to the classification by the World Health Organisation (WHO) and the Genetic Modification Advisory Committee of the government of Singapore.

Bacterial work and Mammalian cell culture are performed in separate BSL2 Biosafety Cabinets, while DNA work is done on the bench. No cytotoxic reagents are used in our laboratory; Sybr Safe DNA stain is used rather than Ethidium Bromide. Liquid biological waste is decontaminated using 10% Bleach, while Solid biological waste is sent for incineration in a local incineration plant devoted to medical waste (Sembcorp).

For the fulfillment of requirements for safety from the iGEM foundation, we have submitted the About Our Lab safety forms and the Final Safety form.

We have also performed a check-in for the Biobricks Part Bba_k299812, which contains the invasin gene from Yersinia pseudotuberculosis and the listerolysin O gene from Listeria monocytogenes.