To prevent potential leakage and avoid liquid culture handling for users, B. subtilis cell cultures are immobilized in PEG-PVA hydrogel, and capsules are used as containers for the hydrogel biosensor. Furthermore, home-based bleach is employed as a killing agent to effectively kill the genetically modified bacteria embedded in the hydrogel test kit [1].

Our experiments were conducted in the InnoLab at HKUST with the following safety equipment:

• 1. Biosafety Cabinet
• 2. First Aid Kit
• 3. Fire Extinguisher
• 4. Flame Retardant Benches
• 5. Spill Kits
• 6. Doors with electronic locks (for restricted access)

The Innolab is also within close range of a safety shower and eyewash station.

Members are required to label all solutions and bacterial plates with the proper names, dates, and names of the handlers. In addition, specific waste bins are set up for proper disposal of waste (one bin for general waste, and two bins for bio-hazardous waste). Pipette tips, agar gels, Eppendorf, gloves, falcon tubes, used plates, and cuvettes are disposed of using bio-hazardous bins. The further processing of bio-hazardous waste will be conducted by the Health, Safety and Environment Office (HSEO) at HKUST to prevent potential contamination or pollution to the environment and society.

Under the supervision of iGEM team advisors and instructors, members conduct experiments in the InnoLab within working hours to prevent accidents.

In order to be granted access and permit to operate in any laboratories at HKUST, students are required to study and pass safety training courses offered by the Health, Safety and Environment Office (HSEO) as part of the university policy. Therefore, students working in the InnoLab are no exception and must comply strictly with this rule. Members are well informed about the potential hazards in laboratory settings, and the steps and procedures to mitigate and properly handle possible accidents.

The online courses that all members are required to pass before working in the InnoLab are:

• 1. Biological Safety
• 2. Chemical Safety I: Chemical Safety for Laboratory Users
• 3. Chemical Safety II: Hazardous Waste Management

Apart from the mandatory training courses provided by the Health, Safety and Environment Office (HSEO) at HKUST, wet lab members would also be receiving an intensive, 3-day wet lab training program provided by the advisors to familiarize themselves with the working conditions, lab techniques, and safety precautions that are crucial in performing any kinds of wet lab experiment. Furthermore, members were taught about the appropriate procedures for general protocols, including but not limited to gel electrophoresis, miniprep, inoculation, plate streaking and spreading, etc.

Throughout our amazing journey in synthetic biology, our team used DH5α competent E. coli strain and B. subtilis 168 strain. Both strains of bacteria are classified under the Biosafety Risk Group 1 and were always handled with aseptic techniques.