Can I stop these from lighting on fire using DNA?

(upbeat music) Potentially.

That smells unhealthy.

Like we talked about last year when we were lighting Christmas trees on fire, something being flame retardant means that it will slow a flame's spread and also help reduce smoke.

And some papers, over the past 10 years, have suggested that DNA can be used as a flame retardant.

So, obviously, I had to try this out.

Now, to test this, I started by replicating everybody's favorite middle school science fair experiment, a strawberry DNA extraction, except I did this on a much larger scale.

The process is pretty straightforward.

Break apart strawberries by smashing, blending, or squishing them.

Lyse or break the cells open using a solution of salt and dish detergent.

The dish detergent can help break apart the cell membranes, and the salt helps knock proteins off of the DNA.

Then, pour cold isopropyl alcohol over the top.

The DNA is soluble in water, but not the alcohol, so it will precipitate out, and you can just pull it right out of this mixture.

Look at all this DNA.

It's probably DNA plus some proteins, but like look at that.

That's wild.

Now, my resulting strawberry DNA is really low purity.

There is, for sure, a bunch of other proteins and molecules in here, too.

So I did try and get a really high-purity DNA sample by washing it and alternating lysis buffer and isopropanol steps, which gave me this very small, but probably much higher purity, DNA pellet.

Okay, so just for fun, this is a piece of pretty pure DNA.

This is the one I wound off of the spool last night from the strawberries.

(match clicking) And when I let that pellet on fire, it burned, but it also went out pretty quickly.

This feels like good evidence that coating clothing in it might also act as a flame retardant.

Interesting.

It did char.

Okay, now let's try a teeny-tiny piece of the salmon DNA.

So it does burn, but it didn't, like, poof, you know?

It did kind of stop itself.

I think that's what it's supposed to do.

Now, this paper claims that DNA is a good flame retardant because when you burn the molecule, three things happen.

First, when they burn, the phosphate groups in the sugar phosphate backbone can create phosphoric acid.

The nitrogenous base, the As, Ts, Cs, and Gs, also contain nitrogen, and so they can create ammonia.

When they burn both ammonia and phosphoric acid, it divert atoms away from the hot burning flame chemistry and towards the charcoal or char chemistry, which burns at a higher temperature.

So basically, they're cooling down the flame chemistry.

The sugars in the backbone can also act as both a carbon source and a blowing agent, which create an Intumescent char that basically acts as a protective layer between the fuel source and the flame.

So, all of this together can help make a flame retardant.

So, I extracted a bunch more strawberry DNA for testing.

And you know what?

I decided that purity here is a little less important than quantity.

It's, like, the pillars of creation in here.

I want lots of DNA, and I know I'm losing some of the wash steps, so I just extracted a big quantity, and we'll see how it goes.

It did pick out some wayward strawberry seeds, though.

Now, the paper I was using for reference actually uses herring sperm DNA as their DNA source.

And that was a little hard to get, so instead I used salmon sperm DNA.

Now, let's talk about some salmon sperm.

Now, look, why salmon sperm?

This is a question that I asked myself a lot in graduate school because almost every molecular biology lab has a vial of salmon sperm in the back of the freezer.

And the reason is because we use it as a sort of standardized blocking agent.

When you just need a lot of DNA in the lab to do something, you use salmon sperm DNA, or just salmon sperm.

I just wanna acknowledge at this point in filming that I recognize all the dirty jokes that I could be making, and I'm not making them, and I hope that the comment section also refrains.

And a group text that I was in a couple years ago, we wanted to figure out why this is because that's what our group text discusses.

And we looked up some of the original papers, and it seems like one of the labs that was doing these first molecular biology techniques was down the road from a fish processing company.

So, they contacted them and they asked them for a whole bunch of salmon testes because it's pretty easy to get the DNA out.

Basically, they grind it up and they do exactly to it what I did to the strawberries.

You lyse the cells, you precipitate the DNA, you dry down the DNA.

It's become a really useful tool in molecular biology when you just need a bunch of DNA, salmon sperm is the go-to.

When you hear about fancy celebrities getting, like, polynucleotide facials where they're getting DNA injected into their faces, it's usually salmon sperm 'cause that's just like the cheapest place to get DNA.

So, just know that if you're going for all those facials, I'm not telling you to do it or not to do it.

I just want you to be an informed consumer.

I remember what I was saying.

We're not making... We're not making jokes, but this solution is a lot more viscous than I anticipated it would be.

So, we're just gonna float these guys in some warm water to try and encourage this process to speed up.

I cut equal lengths of either cotton, acrylic, or wool yarn.

Okay, and bathe them in either water or 2.5% solutions of the different DNAs.

Let them dry.

And then made my own kitchen-style horizontal burn test.

(match clicking) And this was actually pretty hard to interpret.

You know, I still don't own a lighter.

(match clicking) So the strawberry-treated acrylic really struggled to light.

And while the water and salmon-treated ones did light, they did both self-extinguish.

Eventually.

So, it's hard to really draw a conclusion here.

Huh.

Interesting.

For the wool yarn, none of the three conditions lit well.

Ugh, that smells like burning hair, which makes sense.

And for the cotton, the water and strawberry burned out quickly, but the salmon kept going.

What is happening?

In fact, it was like the DNA fed the flame a little bit, but it left behind a char in the shape of the fibers, which was really interesting.

But this was all a little hard to interpret, so I reached out to a scientist who works in this field and asked for some advice.

Okay, see, now that's the opposite of what I thought was gonna happen.

He suggested a vertical burn test and heating the DNA with my yarn when I was coating it.

And we're gonna put that in our water bath.

Okay, so I did that, I retreated my yarn, I rigged up a silly little vertical burn chamber, and I gave it a go.

The scientists I contacted did say that in their best tests, it was like stiff like cardboard.

So, (tray rustling) I really tried to load it up with DNA.

Now, let's take this outside.

And the results were fascinating.

For the cotton yarn, the water and strawberry DNA conditions burned away to almost nothing, but the salmon DNA condition left behind charred fibers and typically self-extinguished.

The fibers weren't very stable after, but it was definitely different from the other conditions, and it was repeatable, and it really did look like I just had sort of char leftover in the shape of those fibers.

This is very cool.

For wool and acrylic, both the strawberry DNA and the salmon DNA protected the yarn from catching on fire.

It was definitely possible to light them on fire if I left the flame there long enough, but it was much harder than the water-treated controls.

If you were just passing one of these over a flame, the DNA definitely protected it from catching better than just the water condition.

So I replicated the paper, but what else can I do with this?

I thought about making maybe a flame-retardant paint, and you can, you can just paint this sticky DNA on stuff, but, like, what am I gonna do with that?

Clothing would be kind of tough.

It would be pretty stiff.

Not very washable, either.

So, I crocheted some of the wool yarn into a pot holder because what about a flame-resistant pot holder?

Is this the Christmas gift that I'm giving everybody for Christmas this year?

(lighter clicking) I mean... No.

It does work, okay?

This is... It's really, it's not lighting on fire.

But again, this is not super practical.

So the way that I think that this would be most useful is as like an inner layer in, say, fireproof gear, or maybe in like outdoor wear.

But it's not great on its own.

I don't know, what do you think?

What should I try and fireproof?

Give me some Shorts ideas, YouTube.

Let me light some things on fire.