Biosafety cabinet

Operations involving infectious agents or organisms will require further measures to ensure bio-security and safety. This usually involves the use of biosafety cabinets, which are designed to protect both the product and the user from contamination. Appropriate disinfection and bio-containment procedures must be adopted to prevent unwanted release of dangerous organisms. 

BSL 2 Biosafety Level 2 is suitable for work involving microorganisms of moderate potential hazard to personnel and the environment. Safety equipment Class I or II biosafety cabinets or other physical containment devices laboratory coats, gloves, face protection as needed. Microorganisms include hepatitis B virus, HIV, salmonellae, and mycoplasma. 

When the quality of the API can be affected by microbial contamination, manipulations using open vessels should be performed in a biosafety cabinet or similarly controlled environment (Q7A Section 18.3). 

Researchers should be familiar with basic sterile cell culture techniques, the ability to grow, passage, and plate cells. All work is conducted in a laminar flow biosafety cabinet using sterilized reagents and equipment. 

The first step of the extrachon procedure, i.e., the denaturation of the sample with the lysis buffer, should be performed in a class II biosafety cabinet. The remainder of the procedure can be carried out on the bench, because the lysis buffer completely inactivates HIV. 

In a biosafety cabinet, prepare a six-well plate with one weU containing 70% ethanol and four others 2 mL of DMEM. Surface sterilize each femur by rapidly passing it in 70% ethanol, rinse it with DMEM in the next well, and then transfer it in the third well. Scrape off any remaining tissue around the bone, transfer the clean bone into the next well and cut both ends with a scalpel. 

Figure 3.26 Class II biosafety cabinet components in chemical fume hoods.

In consequence of both a smaller front opening, 8 to 10 inches, and the fact that only 30% of the air is being discharged at any one time, the amount of tempered air needed to be provided for a laboratory using this type of cabinet is much less than for a chemical fume hood, typically in the range of 250 cfm for a 4-foot unit as compared to close to 1000 cfrn for the same size chemical hood. It could even be more favorable if the biosafety cabinet exhaust were to be discharged into the room, in which case no additional tempered air would need to be supplied to the room other than that needed to provide the recommended amount for personnel comfort and well-being of the ninnber of persormel normally within the room and to compensate for other heat loads. 

Figure 3.27 Side and partial front view of Class n B biosafety cabinet.

Another version of the Class IIB biosafety cabinet is the total exhaust unit shown in Figure 3.28. 

Since none of the air that has passed through the work zone is recirculated, at least in principle, this type of cabinet could be used for moderate chemical appUcations. However care would have to be taken to ensure that the exhaust filter would not suffer from loading of the filter by chemicals. The different rates of loading of the Met and exhaust filters are a problem for all types of Class n cabinets, but the more compUcated airflow systems of Class IIB biosafety cabinets, where two or more blowers are involved, exacerbate the problems. 

Table 3.7 provides a summary of the characteristics of the three types of Class II biosafety cabinets. Class II biosafety cabinets are intended for low- to-moderate-risk hazards. As a minimum, they should be required to meet the National Safety Foundation (NSF) Standard 49 for Class II (laminar flow) a biohazard cabinetry. The working enclosures and plenums through which air moves should be constructed of materials that are easy to decontaminate, such as staMess steel or a durable plastic. 

Table 3.7. Basic Characteristics of Class II Biosafety Cabinets...

A properly functioning HEPA filter is an essential component in both Class I and Class II units and may be important in some Class III biosafety cabinets. 

Equipment is considered the primary barrier for protection of the employees. Items such as biosafety cabinets, safety centrifuges, enclosed containers, impervious work surfaces, autoclaves, foot-operated sinks, and other equipment specifically designed to prevent direct contact with infectious organisms or with aerosols must be available. Personal protective equipment can also be considered as an effective secondary barrier if engineering controls are not sufficient. These latter items can include, at minimum, a lab coat or wrap-around gown, possibly gloves, masks, or respirators, goggles, and head and foot covers. 

Within the work areas ofthe facility, all activities are confined to Class III biosafety cabinets, or to class II biological safety cabinets used with one-piece positive pressure personnel suits ventilated by a life support system. The facility is to be designed to prevent discharge of microorganisms into the environment. 

Laboratory Safety Biosafety Cabinets (BSCs) Fact Sheet (OSHA FS-3460— 2011). 

Handling of retrieved implants and tissues may pose safety concerns for laboratory personnel. As a precautionary measure, retrieved implants should be sterilized and disinfected carefully. In cases where implants cannot be sterilized prior to analysis due to protocol requirements, extreme care should be taken to use an aseptic technique. Barrier clothing, gloves and biosafety cabinets should be used. A detailed discussion of precautions to be used in handling of human tissues can be found in ISO 12891-1. 

A safety cabinet is a laminar down flow cabinet, which is constructed specifically for protection of both the sterile product and the operator. It is frequently used in (hospital) pharmacies for aseptic preparation (when products are not fully closed) and for aseptic handling of class 4 or 5 substances (see Sects. 26.5.2 and 26.8). Laminar down flow has the advantage compared to cross flow that the operator does not feel the continuous flow in his direction. Other names for a safety cabinet are biosafety cabinet, biosafety bench, biohazard bench, biohazard cabinet, biological safety cabinet etc. 

Setup all reactions in the biosafety cabinet and keep all reagents and reaction products on ice while conducting the following protocol ... 

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