Sterile work area

The simplest and most economical way to reduce contamination from airborne particles and aerosols (e.g., dust, spores, shed skin, sneezing) is to use a cell culture hood. There are 3 kinds of cell culture hoods: Class I for microbiological techniques, Class II for routine cell culture procedures and Class III for special handling of potentially hazardous materials.

Airflow characteristics of cell culture hoods

Cell culture hoods protect the working environment from dust and other airborne contaminants by maintaining a constant, unidirectional flow of HEPA-filtered air over the work area. The exhaust filter provides environmental protection, while the downflow filter provides culture protection. Flow can be horizontal or vertical, but the latter is the preferred option since it provides protection to both the culture and the user.

Figure 1: Schematic representation of the air flow in a cell culture hood (left) including particles that HEPA filter blocks (right).

Basic recommendations

• The cell culture hood should be properly set up, and be located in an area that is restricted to cell culture that is free from drafts from doors, windows, and other equipment, and with no through traffic.
• The work surface should be uncluttered and contain only items required for a particular procedure; it should not be used as a storage area.
• Before and after use, the work surface should be disinfected thoroughly, and the surrounding areas and equipment should be cleaned routinely.
• For routine cleaning, wipe the work surface with 70% ethanol before and during work, especially after any spillage.
• Leave the cell culture hood running at all times with the sash at the indicated level, and turn it off only when it will not be used for extended periods of time.