How Mark Rober's DNA Nerf Guns Could Lead to Medical Breakthroughs

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

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When Mark Rober set out to break the record for world's smallest Nerf gun, he never expected he'd end up making more mini Nerf guns than the total number of actual Nerf guns ever to exist.

In his yearlong mission, Rober ended up breaking the record five times by collaborating with leading experts and employing different engineering techniques. 

His first few batches of mini Nerf blasters were made possible by drastically simplifying the design of the Nerf gun. "All materials are springs, even glass," Rober told CNET in an interview. "You just take advantage of that springiness [to] build all the hinges and the springs into one part."

This one-part design broke the record a few times but eventually reached its limits. At 1,000 times smaller than a standard Nerf gun, about the perfect size for an ant, the mini Nerf guns were still able to fire. They had to be fired with a micro-manipulator, however, since human hands and tweezers would not be precise enough to do the job.

Beyond that, Rober says a fireable Nerf gun "could be done," but that the tools required were so expensive as to put it beyond the scope of his video.

Despite no longer being fireable, Rober kept going smaller, in part to protect this particular record from his friend and rival in world-record breaking shenanigans, YouTuber Jimmy Donaldson, aka Mr. Beast. 

Before wrapping up his video, Rober learned of a technique called DNA origami being studied at the Salk Institute and decided to make one last batch of nano Nerf guns.

This technique takes advantage of the fact that DNA naturally binds up when complementary strands are placed in solution together to build out specific shapes. In this case, the right DNA strands placed in the right temperature solution for the right length of time produced trillions of nano Nerf guns. 

At 100 nanometers in length, they're smaller than the wavelength of visible light, so "light can't even bounce off them to get back to your eye." Rober explained that in order to view their creations, they needed the help of an atomic force microscope.

The technology behind these record-shattering mini Nerf guns could also be applied to medical breakthroughs. Rober explains that DNA origami techniques might be used someday to hack the human body's biological mechanisms. For example, he says, "if you had 1.2 trillion mini Nerf guns that instead of firing darts were firing something ... to kill a bad cell, cancer or fortify a good cell."

To see our full interview with Rober about his record-breaking nano Nerf guns, check out the video in this article.