If you are thinking about what aseptic environment that suits you best for working with your experimental samples? And confused between whether you need to go for a Laminar Airflow or choose a Biosafety Cabinet? Whether it is your samples you are looking for a sterile environment or you are working with an extremely contagious samples and concerned for your own safety as well?
You will get your answers by the time you end up reading this article.
Although efforts to preserve and maintain pure cultures of bacteria had begun, it was not until human laboratory acquired infections occurred that attention was given to the protection of personnel. The first survey was published in 1915, when scientist presented data on 50 cases of laboratory-acquired Infection that occurred in Germany between 1885 and 1915. And it keeps happening till Air Flow Hoods got invented.
Air Flow Hoods are of two types:
- Laminar air flow
- Biosafety cabinet
These are simply enclosed protection compartments used in laboratory environments but offering different level of protection. Both of the equipment has one feature in common that it provides clean working environment but these instruments should not be considered common.
Laminar air flow provides a space to work with a product or specimen where it will be protected from contamination by particulates such as microorganisms. So, it protects Products only.
On other hand Biosafety cabinet gives a clean space to work providing protection not only to Product and environment but the User as well. This is the key difference between two.
Working with Laminar Air Flow (LAF):
LAF is a sterile bench cabinet that passes filtered air through HEPA filters while maintaining a constant air velocity in a particular direction. This unchanging parallel direction is the key that avoids cross-contamination.
The continuous air blowing across the Laminar hood maintains sterility inside the chamber that makes it an extremely suitable environment to work with samples that can be only maintained under a clean and sterile environment.
Laminar flow systems are used in industries where it’s difficult to keep the working environment clean and with no biological and particulate contamination. Examples include medical, pharmaceutical, scientific, and electronics fields. Here are some areas where laminar Air flow can be used :
• Cell culture experiments
• Preparing and pouring bacterial growth media
• Preparation and supply of sterile pharmaceutical products
• Quality control and sterility testing
• Production and validation of medical devices
• Electronic and optical assemblies and systems
Working of Biosafety Cabinet:
Development of Biosafety cabinet was lengthy process. Biosafety Cabinets are defined by the National Sanitation Foundation (NSF International) as:
“A ventilated cabinet for personnel, product, and environmental protection having an open front with inward airflow for personnel protection, downward HEPA filtered laminar airflow for product protection, and HEPA filtered exhausted air for environmental protection.”
When Laminar air flow got invented, it needed to be kept in clean environmental room. Aerospace and electronics industries used this clean room environment, as did the pharmaceutical industry and hospital & healthcare industry. However, these clean environmental rooms were very expensive to construct and costly to operate and maintain. Furthermore, once established, most clean rooms could not be relocated.
Laminar Air flow cleans environmental air of room through a HEPA filter, which is blown across the workspace and out toward the user and the lab. Thus, the basic laminar flow clean bench provides no protection for the user from chemically hazardous or infectious materials, including particulate or volatile hazards, and aerosols. Such protection necessitates a biological safety cabinet
Need For Biosafety Cabinet (BSC):
BSC must be used when additional protection of the user and the environment is also required. BSC are designed to remove potentially dangerous biological agents before the air is drawn outside. As a result, all micro-organisms, viruses, and bacteria are kept inside the enclosure. These cabinets are often used in laboratories to conduct research, clinical trials, and different kinds of experiments.
Biological safety cabinets come in several classes (I, II, and III) that offer varying levels of protection to user and sample.
Class I: Solely for operator protection
A Class I cabinet is defined as a ventilated cabinet for personnel and environmental protection. Class I cabinets do not offer product protection from contamination, significantly limiting their applications.
Class II: Operator, product, and environmental protection
A Class II cabinet is defined as a ventilated cabinet for personnel, product and environmental protection. These are designed with an open front with inward airflow (personnel protection), downward HEPA-filtered laminar airflow (product protection) and HEPA-filtered exhaust air (environmental protection). These cabinets are further categorised by types based on construction, airflow and exhaust systems. The types include A1, A2, B1, B2 and C1. They require all biologically contaminated ducts and plenums to be under negative pressure or surrounded by negative pressure ducts and plenums. Class II cabinets are safe for work using agents requiring Biosafety Level 1, 2 or 3 containments.
Class III: Operator, product, and environmental protection for specialized laboratory facilities dealing with deadly pathogens
A Class III cabinet is defined as a totally enclosed, ventilated cabinet with leak-tight construction and attached rubber gloves for performing operations in the cabinet. Class III biosafety cabinets are also called glove boxes. The cabinet has a transfer chamber that allows for sterilizing materials before they leave the glove box. The cabinet is maintained under negative pressure and supply air is drawn in through HEPA filters. The exhaust air is treated with either double HEPA filtration or HEPA filtration and incineration. Class III cabinets are safe for work requiring Biosafety Level 1, 2, 3 or 4 containments.