Whether you’re about to become keeper of the cells, or are just passing through to run a pilot study, knowing how to use the biosafety cabinet is just as essential as knowing how to use the fume hood when working with non-crawling, chemical reagents. We’ve seen a brief protocol for how to use the biosafety cabinet, but what are some other good things to know in practice?
1. Understand What Kind of Lab Hood Is Helping Keep You – and Your Cells – Contamination Free
If you’re joining BitesizeBio for the first time, the first part of this series looked at the differenttypesoflabhoods that you can find in a laboratory. Commonly, the type of hood you’ll see in a academic research laboratory is a class 2 hood built for biosafety level-2 organisms.
2. Keep the Lab Stocked with Bleach and Ethanol
These reagents are diluted to working concentrations for wiping down the workbench before and after an experiment (10% bleach then 70% ethanol) and disinfecting your tools and supplies during it (70% ethanol). While these solutions are often shared among lab members, one good idea is to fill up a couple of spray bottles each morning to keep on hand at the biosafety cabinet.
3. Plan Your Waste Management
Beginning with a large flask or beaker containing a small volume of bleach for collecting old media, another beaker for dry items like pipette tips and lab wipes, and a 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 clean up at the end.
4. “Spray as You Go in, Spray as You Go out”
This is a simple way to remember that everything moving in and out of the hood through the air wash – including your gloved hands – deserves a disinfecting spray of ethanol. After the spray mist evaporates, or is wiped down, continue on!
5. Organize Your Workspace Strategically
Stage clean tools and sterile supplies on one side of the hood, your cells and tissue in the middle portion of the workspace and small buckets and collection flasks for tips and discarded waste media on the opposite side.
With all items set back 4-6” inches from the sash and grouped materials 10-12” apart, you are engineering out the possibility of cross contamination from airborne aerosols, liquid droplets and splashes!
Do note that your workspace includes the immediate area around the outside of the biosafety cabinet, too. How you arrange 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. Though, Do Be Mindful of How You Move…
…to keep lab air from mixing with hood air and vice versa. Fast, pronounced arm movements may disrupt the laminar airflow at the sash leading to an exposure of airborne contaminants. Slow, deliberate movements are best and, if you able, plan experiments during low lab-activity periods as commotion in and out of, and around, the lab may affect the hood’s airflow in the same way.
7. Keep bottles and plates covered…
…when not in use. This helps your cultures remain contaminant-free!
8. Tilt bottles and tubes at a slight angle while pipetting…
…to expose samples to only a sterile pipette. When pipetting vertically, air blows directly into the containers after flowing over your hands, arms and pipettor, risking the chance of contamination from common items.
9. Wipe-down the hood before you start and after you finish
Tissue culture hoods are clean environments, but they require proper practice 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 make sure you 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 the hood on a regular basis
Some labs have a rota for tissue cleaning whereby the hoods are disassembled on a regular basis (e.g. once a week or once a month) and given a thorough clean. If your lab doesn’t have such a practice make sure you at least do a deep clean regularly to ensure your own work doesn’t suffer. Perhaps you can convince others to lend a hand?
11. Use an ethanol-resistant pen for labeling…
…tubes and plates, otherwise you’ll watch the disinfectant spray wash the ink away…
12. Finally, consider double gloving
Cultures may or may not harbor an invisible pathogen, but even still, it’s a double layer keeps bad bugs off your skin in case of micro tears, rips and splashes.
So there you have it! A brief introduction to the types of hoods around your lab – and how to use them!
Graduate students in the United States are privileged when it comes to picking their prospective labs: most programs have student rotate through several laboratories to help them choose their PhD lab. Here are some suggestions for questions to ask.
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