Principles of UV Lamps for Biological Safety Cabinets

Principles of UV Lamps for Biological Safety Cabinets
Germicidal UV lamps have been used in Class II biological safety cabinets for decades. The goal is to keep the interior of the biological safety cabinet clean when not in use. Many researchers swear by their UV lamps and would never consider owning or buying an enclosure without a UV lamp. Others argue that UV lamps provide a false sense of security, or fail to see the benefits of UV lamps (such as NIH). Germicidal lamps utilize UVc radiation (usually 254nm wavelength). This energy is very good at one specific task, but it's a poor broad-spectrum stain remover, here's why:

OK:
UVc is the recommended accessory for BSC or laminar flow benches when working with cell cultures, PCR or other genetic material, as UVc radiation is effective at breaking down chemical bonds and denaturing DNA and RNA. Under prolonged exposure, these chemical changes lead to dysfunctional genetic material and ultimately cell death.

bad:
Germicidal lamps use low-energy radiation - so low that waves cannot penetrate obstacles or reflect off most surfaces. This simply means that in order for the UV lamp to be effective, the target must be directly aligned with the light source. This is not good if you are using germicidal lamps as the primary decontamination agent in your lab incubator. However, for those filling the lab or standing outside the enclosure, it's a good thing to have nothing but a piece of glass and a blue light pipe. This means that the glass plate is enough to stop you from being irradiated.

ugly:
The use of UV lamps for primary decontamination is rampant, as is the frequency of cross-contamination. It is true that cross-contamination can be caused by a number of factors - but experience has shown that laboratories utilizing UV lamps as the only means of "cleaning" their BSCs have a higher prevalence of such problems.

Two simple rules for using UV lamps
If you're working with "naked" DNA/RNA or doing PCR... UV lamps are great for making these materials harmless.

If you're doing anything else with biomaterials...don't just rely on UV lights to keep your work area clean. Always wipe exposed surfaces with a suitable stain remover before turning on the UV light. Always wipe exposed surfaces with a suitable stain remover after turning off the UV lamps.