How Mark Rober's Rivalry with Mr. Beast Led to a Nerf Gun Made of DNA

Speaker 1: It's smaller than that actual wavelength of light. Light can't even bounce off it to come back to your eye. Speaker 2: When Mark Rober set out to make the world's smallest Nerf gun, he didn't know it would lead to this. I talked with Mark to learn about how this saga could lead to medical breakthroughs, how his friendly rivalry with Mr. Beast pushes both of them to greater extremes, and what inspired him to make a Nerf gun out of DNA. Speaker 1: What inspires me to do any of the dumb stuff I do on my YouTube channel? I don't know. Speaker 2: Mark also holds the record for [00:00:30] the world's largest Nerf gun, which he built himself, but going smaller into such an extreme degree presented new challenges. So Mark, with the help of some experts, first set out to simplify the Nerf gun and try to get the whole thing in just one part. Speaker 1: All materials are springs. Even glass technically is a spring, but it's just so stiff. You can hardly see how much it's bending. You just take advantage of that springiness. You can build the hinges in the springs into one part. So that's kind of how we accomplished it. Speaker 2: This [00:01:00] one part design broke the record a few times, but still reached its limits. Speaker 1: We got to the size of three orders of magnitude smaller, so a thousand times smaller than a Nerf gun, and it was still fireball. So it's like it's perfect scale. If you're an an and you have a bunch of buddies and you're going to have a nerve fight, I got you. And I couldn't even use tweezers because my hand's way too rough. We had to use a micro manipulator and barely turn a screw, and it barely pulls this thing back to cock it back and fire it. And then beyond that, it could be done [00:01:30] with very, very, very expensive instruments. But for the sakes of this video, it's just way out of scope. Then we started just making the shapes of Speaker 2: Them, Speaker 1: Which I would argue is still, it is a Nerf gun. It's just a non-functional one. It looks like the outline Speaker 2: Mark kept going smaller in part because of his friendly rivalry with Mr. Beast. Speaker 1: We're friends. I've done a few world records. In fact, whenever he breaks one of mine, usually I'll fly out and help him break it. But in this case, once I learned about the DNAI was like, oh, there's [00:02:00] actually, there's still some room here, so I need to protect this one against Mr. Beast. Speaker 2: Before finishing his video, mark learned about a technique called DNA origami being studied at the Salk Institute and decided to make one last record shattering batch of nano Nerf guns. Speaker 1: Because in nature, they automatically DNA binds up. You create these staple strands that will bind to the one half of the DNA and lock it into whatever shape you want. And then all you do is you take a bunch of those staple strands you could order online that have a very specific sequence of DNA [00:02:30] and then a base strand that has a very specific sequence of DNA. You throw that into a test tube at just the right temperature for just the right amount of time, and it literally self-assembled Speaker 2: To even check their work required very special tools. Speaker 1: It's a hundred nanometers in length. Now, the wavelength of light on average, 400 to 700 nanometers light can't even bounce off it. To come back to your eye, we had to use an atomic force microscope, which is basically a lever arm that goes out and it just [00:03:00] feels its way back and forth across the surface. And then when encounters something as small as a single atom, it moves up a little bit and then when it passes by that atom, it moves down and then you're shining a laser off that lever so you can accentuate the movements up and down. And sure enough, when we did it, we saw in a single drop of saline solution, there was 1.2 trillion of the world's smallest Nerf guns. There are now more of the world's smallest Nerf guns than there ever have or ever will be. Actual [00:03:30] Nerf guns in a single drop. Speaker 2: The technology behind Mark's final and smallest Nerf guns might hold the key to some medical breakthroughs. Speaker 1: When you think of like, oh, robots in your bloodstream that can help in the future. It's looking like machines made of metal and clicking parts and gears and batteries, right? But it's not that with a very targeted approach. If you had 1.2 trillion mini Nerf guns that instead of firing darts we're firing something like the right sequence of whatever to kill a bad cell cancer, [00:04:00] or to fortify a good cell hijacking what we would call natural biological machines our body's already making, but kind of tweaking them and rewriting them in a way that's even more beneficial for ourselves. Speaker 2: Check out Mark's fantastic in-depth video for much more from the team of leading experts he assembled to make these mini Nerf guns a reality. As always, thanks so much for watching. I'm your host, Jesse Oral. See you next time with the fam.