The iGEM competition places great emphasis on biosafety and responsible innovation, with the safety of synthetic biology projects being one of the core evaluation criteria. Our team has integrated safety principles into every stage of project design, experimental operations, and technology application. We paid special attention to the environmental release risks of genetically modified organisms (GMOs) and implemented strict measures at all stages to ensure compliance with biosafety and ethical guidelines.
We selected indigo as a reporter molecule. It is a natural pigment widely used in the food and textile industries and exhibits high biosafety [1]. Its synthesis pathway originates from natural microbial metabolic processes, making it non-toxic and environmentally friendly, with no adverse effects on ecosystems or human health [2].
Figure 1: The structural formula of indigo
Salicylic acid is a natural elicitor of plant immune responses, capable of activating systemic acquired resistance (SAR) in plants. This enables infected plants, both locally and systemically, to develop broad-spectrum and long-lasting resistance against subsequent pathogen attacks [3]. Through controlled localized expression, our team maintained the functional concentration within a range that can be safely metabolized by the plant-soil system (reference concentration: 0.1–1 mM) [4]. At this concentration, salicylic acid degrades naturally without accumulating in the soil or affecting the microecology [5].
Figure 2: The structural formula of salicylic acid
Although directly applying engineered bacteria could enhance detection and treatment efficiency, to completely eliminate the risks of horizontal gene transfer and environmental dissemination of GMOs, we abandoned open application strategies. Instead, the team developed a closed detection system: soil samples are collected and reacted with engineered bacteria in disposable collection tubes, achieving a "sample-in-result-out" detection model that physically prevents the leakage of engineered bacteria.
Figure 3: Engineered bacteria in sealed disposable tubes (powder shown for illustration only).
We compiled a team safety manual that systematically outlines comprehensive operational protocols to ensure the safety of laboratory personnel and the environment. It covers key aspects such as personal protection, use of chemicals and biological materials, waste disposal, and emergency response to accidents, requiring strict adherence from all members. This manual aims to provide a reference framework for future iGEM teams to systematically identify and manage risks during experiments.
To ensure strict adherence to laboratory safety protocols, our team developed a comprehensive Laboratory Safety Test based on our safety guidelines. All team members thoroughly studied the safety manual and subsequently completed the test, which covered critical areas including biosafety procedures, chemical handling, emergency response, and waste disposal. The test results demonstrated a strong understanding of safety principles, with all members achieving excellent scores. This process effectively reinforced our safety awareness and ensured our team is fully prepared to conduct experiments in a secure and responsible manner.
All team members received comprehensive biosafety training and operational assessments before conducting experiments. Throughout the experimental process, experienced teaching assistants and instructors provided on-site supervision to ensure standardized experimental operations, proper use of personal protective equipment, safe handling of biological materials, and compliant equipment operation, minimizing human errors and accidents.
Figure 4: Students conducting experiments under the guidance of teaching assistants
To integrate safety knowledge into the practical environment, we systematically organized and photographed key safety signs in the laboratory (see figure group, labeled A, B, C, D, E, F), including:
A. High-temperature equipment warnings: Used for autoclaves, ovens, etc., to prevent burns.
B. Biohazard signs: Used for waste bins containing hazardous liquids, emphasizing the need for protective measures during handling.
C. Fire equipment signs: Ensure quick identification and access to firefighting equipment in emergency situations.
D. Warning signs: Alert personnel to ultraviolet radiation hazards, requiring avoidance of exposure to prevent eye and skin injuries.
E. Prohibition signs: Prohibit the placement of flammable or explosive materials in shaker working areas to prevent fires or explosions.
F. Emergency facility indicators: Include eyewash stations, emergency showers, and exit routes to enhance emergency response capabilities. Through the clear placement and team interpretation of these signs, we further strengthened the overall safety culture in the laboratory.
Figure 5: Laboratory Safety Symbols
From the outset of the project, our team prioritized safety as a core principle:
We firmly believe that responsible research innovation is not only a requirement of the iGEM competition but also an obligation for every synthetic biology team.
[1] Barbara Błyskal. Indigo dyeing and microorganism–polymer interaction [J]. Journal of Cultural Heritage, 2016: 974-983.
[2] Julia A. Linke, Andrea Rayat, John M. Ward. Production of indigo by recombinant bacteria[J]. Bioresources and Bioprocessing, 2023, 10: 20.
[3] Mohd Saleem, Qazi Fariduddin, Christian Danve M. Castroverde. Salicylic acid: A key regulator of redox signalling and plant immunity [J]. Plant Physiology and Biochemistry, 2021, 168: 381-397.
[4] Hayat Q, Hayat S, Irfan M, et al. Effect of exogenous salicylic acid under changing environment: a review[J]. Environmental and Experimental Botany, 2010, 68(1): 14-25.
[5] M. Omar. Salicylic Acid is an Effective Eco-Friendly Technique [J]. Journal of Soil Sciences and Agricultural Engineering, 2019, 10(12):741-746.
