The cabinet already has a UV lamp and UV-A wavelength is not so harmful. I have a clarification, cant we use a UV-A lamp straight away inside a biosafety cabinet used for tissue culture. The cabinet already has a UV lamp and UV-A wavelength is not so harmful as well. Any safety issues?
Although we routinely use UV lamps inside our biosafety cabinets and assume that UV light does not penetrate through matter, there are many reports that suggest this might not be true. Take a look at this report, for example http://www.absa.org/abj/abj/061104meechan.pdf
It seems that the amount of UV light coming out of the cabinet face depends on the quality of the cover, distance at which you are standing, and also the wavelength of the UV that the lamp emits. For example, a cover made of Plexiglass will transmit most of the UV, while a one made of Polycarbonate wont (it will block at least up to 80-90%). Glass does absorb UV, but in a specific wavelength range..
So you must check the specifications of your biosafety cabinet, the UV lamp etc. inside it and consider these factors before you start using your UV lamp for sterilization.
You cannot see the radiation source. You cannot receive light of this source.
Be careful of the emission spectrum of your UVA source(s), some of them emit some UVB (280-315 nm) and can be harmful for biological species i.e. the experimenter...
2-3 nm glass windows will block most of the UVA and the totality of the UVB wavelengths.
The UV lamp inside your cabinet will most likely be a 254 nm UVC lamp for germicidal purposes. Your UVA lamp will, of course, operate at different wavelengths. Is your question asking about the level of protection that would be afforded by the glass screen of your cabinet? If so, then measuring the transmission through the glass will tell you. The glass front may be certified to block all 254 nm UV from the installed UV lamp, but may not provide protection from the UVA wavelengths emitted by your UVA source.
The light exiting through the hand opening will also have to be considered and measured. As the previous answer states, distance from the source must be considered too, when working out your exposure risk.
The level of heat produced by your UVA source may also be an issue, depending on how powerful it is, and how hot it gets. In the enclosed environment of a hood, is the airflow sufficient to keep the temperature under control?
In answer to your question, in theory you could use a UVA lamp in an MSC II to expose cells, providing you perform the dose measurements to demonstrate that the protection offered by the hood is sufficient. UV light does present dangers to the operator, and other lab users, so measurements should be taken, and safe operation ensured.
Maybe you do not 'see' the UV source... that means that you do not receive any direct UV light ... but be very careful for the diffuse light.. due to diffusion, refection, scattering...
A measurement of the transmission of your protection windows will certainly be helpful
all UV Radiation which energy is high enough do interact with chemical bonds is dangerous, in general C-C bonds are considered (there are many C-C bonds in biological tissue) and radiation below 400 nm is dangerous ( skin cancer!!); UVA means 315 - 385/400 nm , so bonds can be disrupted/activated which may lead to undesirable reactions. You need the Absorption curve for your window material; Standard glass does not absorb at wavelength higher than ~300 nm.
On the other side there are many people in "sun studios" with UVA lamps, but they have to wear a blocking glasses (full absorbance lower 400 nm). Therefore it is a question of intensity (direct light, scattered light) duration of the exposure and the sort of tissue.
It has been shown that the interaction of UVA with human skin is irradiance dependent - Probably oxygen dependent, meaning that the higher the irradiance the smaller the observed effect for the same dose. As UVA induced phenomena tend to require higher doses we tend to increase the intensity of the light source in order to minimize the time. Be careful! And make sure that what you are trying to do is not sensitive to oxygen or intensity. When testing for intensity effects you need to change the intensity by a factor of 4 or higher otherwise the effects may be buried in the "biological" noise.
Hi Behin, keeping biological safety cabinets clean and contamination free is super-important. Depending on where and how your safety cabinets are set up, there are a few options. The first thing I always say is that if you are going to use a UV lamp, make sure almost everything is out of the hood, so all surfaces are exposed.
If your hoods are in a separate space, keep the UV light on for an hour after use and overnight periodically. It takes about 30 second to10 minutes of intense UV to kill most microorganisms. You do not need to leave it on all the time for it to be effective. Do not use the UV lamp when people are present in the room! No matter what the characteristics of the cabinet's glass, simply turning off the UV when people are in the room avoids any unwanted or accidental exposure of humans to intense UV. If the hoods are in an area where people are regularly, just turn the UV on overnight after the cabinet has been used.
The last thing to remember is that UV bulbs lose their effectiveness over time. Do not wait for bulbs to fail to replace them! Check intensities regularly and follow manufacturer recommended replacement schedules. Good luck!
yes
you have to use UV lamp in you cabin for 15 minutes of course after you wash your cabin with alcohol 70 percent
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