Our engineered bacteria will be designed as whole-cell microbial sensors based on transcription factors, which can be used to detect arsenic concentrations in the environment. We will construct plasmids expressing the ArsR protein in Escherichia coli (E. coli). This protein binds to its cognate promoter, thereby repressing the expression of downstream reporter genes. Upon induction with arsenite, the ArsR protein dissociates from the cognate promoter, allowing the expression of downstream reporter genes. There will be a linear relationship between arsenic concentration and the signal output by the reporter gene. Based on this, we will construct and fit a dose-response curve, and optimize the limit of detection (LOD) and operating range to enable efficient and convenient detection of arsenic concentrations in the environment.
The safety management and control of this project focuses on three core risks:
The following sections will detail the safety management and control measures of this project from four dimensions: "Design Safety → Laboratory Operational Safety → Personnel Training → HP Activity Safety". All plans comply with the biosafety regulations and the iGEM Safety Guidelines.
Core: Proactively avoid biosafety risks from "chassis selection" to "module design".
| Chassis Strain Name | Source & Background | Biosafety Level (BSL) | Pathogenicity / Environmental Risk | Rationale for Selection |
|---|---|---|---|---|
| E. coli DH5α | A commonly used laboratory cloning strain, purchased from commercial supplier | BSL-1 | Non-pathogenic; unable to reproduce independently in the human body / natural environment | Suitable for plasmid construction; no risk of environmental escape; meets the needs of "laboratory-level detection" projects |
The design mechanism of these engineered bacteria does not support their independent reproduction and spread in the natural environment. Their survival and functional performance depend on laboratory-controlled culture conditions (e.g., specific culture media, temperature). The core function of the engineered bacteria is to respond to arsenic ions through a promoter regulatory system and express reporter genes. They do not possess characteristics for colonization, competition, or spread in the environment, and thus lack the biological basis for independent reproduction. Furthermore, they can be treated using physical and chemical methods such as flame incineration or alcohol disinfection to further ensure safety.
| Safety Dimension | Specific Measures | Responsible Personnel | Emergency Contact |
|---|---|---|---|
| Personal Protective Equipment (PPE) | Laboratory personnel must wear long-sleeved lab coats, nitrile gloves (resistant to chemical reagents), and safety goggles (to prevent liquid splashing) during experiments. | All team members | Laboratory Safety Officer: Wan Junjie |
| Area Isolation | Physical separation between experimental areas and rest areas; eating and drinking are prohibited in experimental areas; reagent storage areas are labeled with "Flammable/Toxic" signs (e.g., ethanol is stored in an explosion-proof cabinet). | Laboratory Administrator | Same as above |
| Emergency Equipment | Each floor of the laboratory is equipped with eye wash stations, fire blankets, and first-aid kits (containing povidone-iodine, band-aids, anti-allergic drugs). | Equipment Manager | University Infirmary Phone Number |
Strain Operation:
Special Chemicals:
High-Risk Operations:
Form a closed loop of "Training → Assessment → Onboarding" to avoid formalization.
| Training Type | Training Content | Assessment Method | Completion Criteria |
|---|---|---|---|
| Theoretical Training | iGEM Safety Guidelines, Biosecurity Law, project safety risks (e.g., hazards of engineered bacteria escape) | Question-and-answer session | Graded as Excellent, Good, Average, or Unqualified |
| Hands-on Training | Use of biosafety cabinets, operation of autoclaves, emergency handling (e.g., how to clean up reagent spills) | On-site practical assessment | Ability to complete operations independently without errors |
| Specialized Training | Use of UV gel transilluminators, large centrifuges, electroporators, electrophoresis transfer units, etc. | One-on-one assessment by equipment administrators | Ability to explain operational risk points |
Daily Supervision: Mentors conduct laboratory inspections twice a week, focusing on checking "PPE wearing, reagent storage, and sterilization records"; Experimental records must include "safety operation notes" (e.g., "BSL-1 strains were used today and sterilized in accordance with specifications"), which must be signed and confirmed by the team leader.
Violation Handling: First violation (e.g., failure to wear safety goggles): Re-attend theoretical training; Second violation: Suspension of experimental qualification for 3 days.
| HP Activity Type | Safety Measures | Emergency Plan |
|---|---|---|
| Professor Interviews | At least two team members (including the one responsible for photography) must be present during interviews; Obtain the interviewee's consent before taking photos. | Prepare umbrellas in advance to prevent illness caused by getting wet in bad weather. |
| Community Questionnaire Surveys | Conduct surveys in pairs of two; Inform the team leader of the survey route in advance; Ensure devices are fully charged and notifications are enabled to maintain communication. | If residents refuse to complete the questionnaire, discontinue attempting to survey that participant. |
| Science Popularization Activities (e.g., Campus Lectures) | Contact local leaders in advance to ensure the smooth conduct of activities; During activities, use PPT presentations + explanations as the main form of science popularization; No laboratory physical samples will be displayed. | If the destination cannot be reached due to weather conditions, reschedule the science popularization activity. |
Survey Data Processing:
Data Disclosure Boundaries:
This project implements full-process management and control from "Design (Proactive Protection Modules) → Operation (Laboratory Specifications) → Personnel (Training and Assessment) → HP (Ethics and Protection)". All measures are designed based on actual risks and can effectively avoid the three core risks of "engineered bacteria escape, personal injury, and privacy leakage", complying with iGEM safety requirements and relevant regulations.