The rapid spread of the new coronavirus brings the virus once again into the spotlight, not only medical and rescue workers in the front line to try to treat, researchers are also in a hurry to carry out virus research and drug experiments. So you might want to know what a lab that conducts a virus experiment looks like? What’s the difference between a biology lab and a testing lab in a hospital? Next, let’s get to know the biosafety lab.
What is a biosecurity lab?
Laboratory is a necessary place for scientific research, and the international classification of biolaboratories into Biosafety levels (Biosafety levels, BSL) is P1 (Protection level 1), P2, according to the level of risk, including the infectious and harmful nature of infectious diseases. P3 and P4 are four levels.
The work that P1-P4 laboratories can undertake is also divided according to the safety level, which is strictly low to high.
P1 Laboratory: Basic laboratory, suitable for human, animal, plant or environmental harm is low, does not have a healthy adult, plant and animal disease factors.
P2 Laboratory: Basic laboratories for causative factors that are moderately harmful or potentially hazardous to humans, animals, animals or the environment, and do not pose serious harm to healthy adults, animals and the environment, and have effective preventive and curative measures.
P3 Laboratory: Protective laboratory, suitable for the treatment of highly harmful to human stoic, plant or environment, through direct contact or aerosols to human infection of serious and even fatal diseases, or highly harmful to animals and plants and the environment of pathogenic factors, usually with preventive and curative measures.
P4 Laboratory: The highest level of protection laboratory for highly hazardous to humans, flora and fauna or the environment, unexplained or transmission routes unknown, or unknown, highly dangerous causative factors. There are no preventive and curative measures. For example, the Ebola virus.
The construction of biosafety laboratories is subject to published Biosafety Laboratory Building Technical Specifications. According to the specification, the P2 laboratory should implement the first-level barrier and the second-level barrier, while the P3 and P4 laboratories need to set up a first-level barrier and a secondary barrier.
The first-level barrier guarantees the isolation between the experimental operator and the subject, including biosafety cabinet and positive pressure protective clothing, and the second-level barrier guarantees the isolation of the biosafety laboratory from the external environment, which includes the ventilation system, so the first-level barrier and the second-level barrier are the protective umbrella of the experimenter and the external environment. The main rooms of the P3 and P4-grade laboratories are also detailed in the building specifications, including the main laboratory, the main laboratory buffer room, the isolation corridor, the protective suit change room, the preparation room, the shower area, etc. Ultra-high cleaning levels, constant range of temperature, humidity and pressure differentials are all guaranteed for experimental safety.
Key technical indicators of the secondary barrier of the Biosecurity Laboratory, Source: Biosecurity Laboratory Building Specification GB 50346-2011
You might wonder what the highest-level P4 lab is really like.
P4 Laboratory, the highest level of biosecurity, is a powerful weapon for dealing with high-risk, unpreventable and untreatable viruses. P4 laboratories are generally a separate building, such as sharing a building with other level biological laboratories, and also require a separate isolated area in the building and completely isolated from other nearby buildings. In the common four-layer structure, one layer is sewage treatment and protection equipment, the second layer is the core experimental area, the third layer is the exhaust pipe filter layer, the fourth layer is the air-conditioning equipment and the air-carrying pipe.
Basic features of p4 Labs Source: National Institutes of Health, Part of the United States Department of Health and Human Services
Protection of persons in biosafety laboratories
When entering a general laboratory, the experimenter only needs equipment such as lab clothes, gloves and facial protection. And there are potentially dangerous causative factors in high-grade experiments, how do researchers protect themselves?
As we mentioned earlier, the level 1 barrier protects the experimenter from potential lymes. Before entering a high-grade laboratory, personnel need to go through a number of procedures, including the outer dressing room, shower room, inner dressing room, buffer room, etc., from the outside to the inside of the laboratory may take 20-30 minutes. As a result, laboratory staff are required to undergo rigorous training prior to induction, and it is important to ensure compliance with the use process. In order for researchers to be isolated from potential pathogens, entering the laboratory requires wearing a separate oxygen-supplying positive pressure protective suit. In protective clothing, the experimenter breathes air from a separate air system and needs to be replaced in the laboratory, which is why many spiral tubes are suspended in the lab.
For laboratories with P2 level s (p2) and above, biosafety cabinets (Biosafety cabinet, BSC) are required to be equipped with the regulations, and the operation of dangerous pathogens is required to be completed in the cabinet. Biosafety cabinet is a negative pressure equipment, according to the circulation wind and exhaust ratio is also divided into different levels, which by the cabinet air constantly pumped out to ensure the negative pressure in the cabinet, to prevent the experimental operation of the aerosol diffuseoutward diffusion. After the experiment is completed, when the personnel leave the laboratory, they will carry out chemical shower disinfection, eliminate all possible contaminated viruses, and finally take off the protective devices layer by layer.
Scenes of experiments in protective clothing in the film “Infectious Diseases”
Footage into the P4 lab in the film “Infectious Diseases”
The box that shuts down the pathogen
Scientists may study dangerous causative factors in the lab, and how does the laboratory ensure that the pathogens inside the lab do not spread outwards?
First, all biological experiments are conducted in laboratories with the appropriate safety level in accordance with the state-mandated microbial safety level (refer to the List of Pathogens of Human Infection at http://www.nhc.gov.cn/wjw/gfxwj/201304/6460196295445c1929e814462d0746c.shtml). Ordinary laboratories do not have the experimental permission to have pathogenic viruses, but need to follow the Microbiology Operating Technical Specification (GMT) in operation, and non-pathogenic virus contact with equipment and consumables need to be disinfected with alcohol or high pressure, waste into a dedicated medical waste garbage bag to ensure biosecurity.
The secondary barrier slabs in biosafety laboratories at all levels ensure that the causative factors cannot escape. The experimenter needs to go through layers of levels to get in and out of the lab from the buffer. For the P3 and P4 laboratories, each door air pressure in the direction of entry will gradually decrease, i.e. the directional negative pressure system, while there are multiple installation chain doors, to ensure that two doors can not be opened at the same time to prevent air circulation. The air inside the laboratory must be filtered through an efficient filter before it can be discharged; the solid waste produced by the experiment must be thoroughly sterilized before it can be treated harmlessly; the sewage generated in the laboratory has been perfected through the sewage treatment system; and the protective clothing worn by the experimenters will not be let go. Strict chemical shower disinfection can eliminate all contaminated pathogens. In short, solids and liquids do not leave the laboratory without treated gases.
Then you might want to ask, what if there’s a power outage? What if the exhaust system fails? Do not worry! High-grade biosafety laboratories have complied with their construction standards, with backup power supplies and backup exhaust fans, continuously safeguarding the negative pressure environment in the laboratory and maintaining laboratory safety. In other words, the biosecurity lab is like a box, using various means to “shut” the pathogen inside.
At present, many biosafety laboratories across the country have joined the research of new coronaviruses, some are carrying out testing work, some are in the hurry to carry out scientific research, in order to solve the epidemic at an early date. Let us pay tribute to the scientific researchers and medical workers who are struggling on the front line!