Whether you are in charge of keeping and distributing cells for your lab or want to run a basic pilot study, knowing how to use a biosafety cabinet is essential.
Because they keep your work safe from contamination, and you safe from your work!
And while following the correct protocol is essential to use them correctly, there are many tips for working in a biosafety cabinet that will enable you to get the most from your experiments!
Here are twelve of them.
What Is a Biosafety Cabinet?
It’s a basic question, but worth knowing.
A biosafety cabinet is not the same thing as a laminar flow hood.
A biosafety cabinet is a sterile working environment that keeps you safe from the bugs you work on, even when they are aloft on aerosols. They do this by drawing air into the cabinet, passing this through a HEPA filter, and exhausting this sterile air into the lab.
Biosafety cabinets suck.
A laminar flow hood also provides a sterile working environment but gives you no protection against the bugs inside it. That’s because it draws air through a HEPA filter and blows it toward you.
Laminar flow cabinets blow.
Now you know that here are some top tips for working in a biosafety cabinet.
Tips for Working in a Biosafety Cabinet
1. Understand What Kind of Biosafety Cabinet You Are Using
There are three classes of biosafety cabinets:
- Class I, for working on containment level 1 organisms.
- Class II, for working on containment level 2 organisms.
- Class III, for working on containment level 3 and 4 organisms.
The most common type of cabinet you’ll see in an academic research laboratory is a class II hood.
2. Keep the Lab Stocked with Bleach and Ethanol
We use 10% bleach and 70% ethanol solutions to disinfect biosafety cabinets. So it’s a good idea to ensure the lab is always stocked with these chemicals so they can be diluted to the working concentration on demand.
While these solutions are often shared among lab members, it’s good practice to fill up several spray bottles each morning to keep on hand in the biosafety cabinet.
3. Plan Your Waste Management
Prepare a large flask or beaker containing a small volume of bleach to collect old media.
Have another beaker to hand for dry items like pipette tips and lab wipes.
And keep biohazard bucket outside, but nearby the hood for discarding larger items, like 25ml serological pipettes.
By pre-sorting your expected waste, you’re one step ahead for a quick and safer cleanup at the end.
4. Clean Before, Clean After
Everything moving in and out of the hood through, including your gloved hands, should be disinfected with a spray of 70% ethanol.
After the spray mist evaporates or is wiped away, continue on!
5. Organize Your Workspace Strategically
Keep clean tools and sterile supplies on one side of the hood, your cells and tissue in the middle, and discarded waste media on the opposite side.
If all items are set back 4–6” from the sash and materials are kept 10–12” apart, you reduce the risk of cross-contamination from airborne aerosols and splashes!
Note that your workspace includes the immediate area outside the biosafety cabinet too.
So arranging easy access to extra supplies like tips and tubes will eliminate the need to pause mid-assay to get up and move about the lab.
6. Be Mindful of How You Move
Fast arm movements may disrupt the airflow at the sash, potentially mixing sterile air with dirty lab air. This increases the risk of exposing your experiment to contaminants and exposing you to your experiment.
Slow, deliberate movements are best.
If you are working on something sensitive to contamination, do your experiment during quiet periods—the commotion in, out, and around the lab may also affect the hood’s airflow
7. Keep Bottles and Plates Covered
Simple enough. This helps your cultures remain contaminant-free!
8. Tilt Bottles and Tubes at a Slight Angle While Pipetting
When pipetting vertically, air may blow directly into the containers after flowing over your hands, arms, and pipette, risking the chance of contamination.
Tilting receptacles slightly enables the air to flow across their aperture and not into it.
9. Wipe It Down Before You Start and After You Finish
Tissue culture hoods are clean environments, but they require proper maintenance to keep them that way. Someone may have used the hood before you and not have been so careful to keep the space clean.
So to make sure you don’t suffer from someone else’s carelessness, wipe down before each use.
Also, you don’t want to get the blame for contaminating someone else’s work, so leave the hood in sparkling condition once you’ve finished.
10. Deep Clean It Regularly
Some labs have a rota for fumigating biosafety cabinets. This might be mandated and organized by the institute your lab is in.
If your lab doesn’t have such controls, ensure you deep clean your tissue culture hood regularly to ensure your work doesn’t suffer. Perhaps you can convince others to lend a hand?
11. Label Items Using an Ethanol-Resistant Pen
Not all pens are equal. Choose the right pen for labeling your tubes and plates. Otherwise, you’ll watch the disinfectant spray wash the ink away and be left scratching your head.
12. Consider Wearing Two Pairs of Gloves
This strategy helps to keep nasty bugs off your skin in case of micro-tears, rips, and splashes. Disposable gloves are thin and prone to failure. Even worse, they might fail without you even noticing!
Tips for Working in Biosafety Cabinets Summarized
They were our twelve top tips for working in a biosafety cabinet. Helpful? You tell us! Drop a comment below if so.
Ditto if you have a tip that you want us to mention.
And if you want to understand a bit more about biosafety cabinets, be sure to check out our biosafety cabinet protocol.
Originally published March 2015. Revised and updated November 2022.