Testing a cheaper laminar flow hood.

Cheaper home science.

This blog tries to figure out how to do meaningful science at home, at cheaper cost.

For biology experiments, the main issue when doing experiments is contamination of your samples. One source of contamination is microbes in the air. This means when I am working with agar plates, there is a risk of them getting contaminated when I open the lid to put my samples on it.

A contaminated plate from my first UV experiment.

One way to prevent contamination is to use a spirit lamp or bunsen burner to create an updraft around your workspace.

But another tool that professional scientists use is the a laminar flow hood. A laminar flow hood fans air through a HEPA filter above the workspace. The HEPA filters out the microbes, and this clean air pushes contaminated air away due to the flow pattern.

Source

HEPA filters remove most particles, including microbes, from the air. They are sheets of packed random fibres that trap things through several methods.

Unfortunately, laminar flow hoods are really expensive, and too bulky to put in your house. I honestly don’t know why these things are so expensive. I’m guessing it’s a premium from the brand name, as well as quality assurance.

But in the last decade, the field of amateur mushroom growing has got big. And people needed a way to maintain clean workspaces. And so, this wonderful community has offered us a solution - cheaper, more compact laminar flow hoods.

From speaking to my professional biology friends, this level of cost was cheap enough to really get them interested. I spoke to around five professional biotech or lab scientists, and they all said this price level was a good deal if it worked.

This is important. If you can tell that your experiment is clean, then whatever works, works! No need for fancy brand names!

So I had to test one of these out. I got this flow hood from ‘Funguyequipment’. Note - I am not sponsored by anyone, nor have I received any special discounts, including from this supplier.

I then put 4 agar plates under the clean air, and 4 agar plates above. I left them exposed for 30 minutes. This is a ridiculous amount of time to leave agar plates open for, since usually you’d only open them for a few seconds. But I wanted to make sure it was left exposed enough to get some contamination.

Here are the results. The plates marked ‘N’ are without the laminar flow hood. 4/4 plates from without the laminar flow hood got contaminated (the bottom right one has a small amount). Whereas only 2/4 plates with the hood got contaminated. Aside from that, you can see the the size of the contamination is a lot smaller on the plates with the flow hood!

Not bad! There are also people trying to make their own by putting a fan in a box and cutting a hole for the HEPA filter, and I’m looking to test that one too.