Laminar Flow Hood
What are they and why do we use them? What types are there?
Laminar flow hoods are used to create a Sterile Workspace for performing Sterile Technique, replacing the traditional Bunsen burner. Incoming air passes through a HEPA filter and is blown out of the hood, towards the researcher. It is important to note that a Laminar Flow Hood is used to protect the work from the researcher - it does little to protect the researcher from the work.
A Biosafety Cabinet is the next step up, which protects both the work and the researcher from each other.
When do you use?
A laminar flow hood is an excellent piece of technology for ensuring you have a sterile workspace for all of your work. Some researchers choose to do all of their work under the hood.
However, access to the laminar flow hood in any lab may be a bottleneck, so it can be important to know which protocols need priority access to the laminar flow space. If possible, you should always use a Laminar Flow space for the production of Competent Cells and Plate Pouring.
It is possible to perform both of these protocols under a simple Bunsen burner, but you may experience some contamination. There are plenty of researchers, especially in the mushroom growing community who have learnt to DIY a Laminar Flow Hood. I’ll link these DIY projects below as I find them;
How do you use?
Use of a Laminar Flow hood requires a proper understanding of the airflow within the hood. You will always want to have your project closer to the air outlet than you - ensuring bacteria/enzymes aren’t blown off your skin and into your project.
Start-up Protocol:
If your Laminar Flow Hood is equipped with a UV light, cover up the front with the panels and turn on the UV light. Make sure there are no gaps for light to leak through and absolutely DO NOT stare at it.
After 10 minutes, turn off the UV light, and turn on the Laminar flow fans. As the suction begins to pull on the front panels, slide them off.
Don’t leave the front panels on for too long as they may be damaged by the air pressure.
Put on your gloves and spray them with 70% ethanol.
Spray the inside of the Laminar Flow hood with 70% ethanol and wipe it down with paper towel.
The Laminar flow hood is now sterile.
As you move your work into the flow hood, spray the outside of each bottle/tube with 70% ethanol and wipe them down with paper towel.
As a general rule, always move an object backwards and to one side after use.
If you need to sterilise an inoculating loop in the hood while using a Bunsen burner, keep in mind that the stronger air flow of the Laminar flow hood will override the traditional cone of protection. The heat will still sterilise, but the air flow will blow the bacteria on the loop back towards you. Set up your workspace with this in mind.