Using Uv Light In A Biological Safety Cabinet

By Author: Dirk Rowell
Total Articles: 115
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There has been long-term conflict within the research community over the use of ultraviolet (UV) light in a biological safety cabinet (BSC).

The current US and EU standards state that UV lights are not required in BSCs, and should be switched off when the room is being used to protect the skin and eyes. Despite this, many manufacturers make provision for ultraviolet lights to be fitted in their cabinets, with many scientists continuing to use them. Research suggests that UV light may have some benefits over other forms of sterilisation, but must be used with extreme caution, owing to the possibilities of skin cancer and corneal burns.

The properties of UV light

The optimal wavelength of ultraviolet light for disinfection purposes lies in the UVC range of 200 – 290 nm. It is an effective germicide and virucide, inactivating DNA and RNA through the creation of major lesions. UVC has minimal penetration properties, but is effective at sterilising an empty cabinet, and cannot leak through the glass (although it can through the uncovered hatch).

Penetration of the skin dermis does not occur below wavelengths ...
... of 300 nm. However, there is some evidence that UVC may be a carcinogen in workers constantly exposed to it over a long period of time, and the risk exists for keratoconjunctivitis, or corneal burn, to develop in some individuals.

Benefits versus drawbacks

In a recent survey in the US, UVC was a popular biocide in tissue culture cabinets. Users also used liquid disinfectants such as isopropanol, but there were distinct advantages in using UV light. These advantages included:

- Prevention of mutation of microorganisms to resistant phenotypes
- Prevention of cross-contamination in PCR (polymerase chain reaction) experiments
- Increased efficiency against vegetative organisms and viruses
- Less hazardous than flammable and oxidising disinfectants

The conclusion was that UV light can be a useful tool in the biohazard safety cabinet, but safety features must be present to protect personnel.

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