Thanks to Linode for supporting this SciShow video! You can get a $100 60-day credit on a new Linode account.
If you love watching videos of single-celled critters wriggling around under a microscope, you’re not alone. But have you ever wondered if there’s footage of even tinier biology? Well, here’s an image of just that: a string of beads that is actually DNA wrapped around some proteins. It looks pretty cool, right? Unfortunately, in order to take a picture of something this small, you have to kill your sample.
But over the past few decades, scientists have developed a new technology that can see really tiny things without killing them. It’s called atomic force microscopy (AFM), and its real-time, small-scale footage is helping scientists study some important stuff, like how to treat cancer.
AFMs don’t need their samples to conduct electricity, so you don’t have to coat them in some conductive metal. You don’t have to freeze them, slice them up, or dehydrate them either. Plus, AFMs don’t have to operate in a vacuum, so they can look at samples while they’re in liquid. This means that scientists can observe life in all its living, gooey glory! Heads up, it’s kind of an “I’m not touching you” game on atom-scale steroids. Atomic Force Microscopes (AFMs) are used by researchers to study live biological samples, using a super tiny probe that wiggles up and down at a very specific frequency and moves along the sample, hovering just above the surface. When the tip of the probe is over 10 nanometers away from the sample, van der Waals forces pull the probe toward the sample, famously allowing geckos to stick to seemingly anything. However, when the tip gets too close, within a few tenths of a nanometer, it gets pushed away due to all of the electrons in the tip and the sample’s surface not wanting to be too close to one another. By tracking the pushing and pulling, and how those forces affect the probe’s wiggling, scientists can figure out where the tip runs into any grooves or bumps, building up a 3D map of a sample, down to the atomic level.
And if you use the right kind of probe, AFMs can do more than map. They can also measure the mechanical properties of the sample, such as surface friction or stiffness. It turns out, some cancerous cells are stiffer than their healthy counterparts, so scientists are currently investigating how to use atomic force microscopy to help diagnose cancer.
But for all its bio-scanning power, the original atomic force microscopes came with one huge flaw. They needed minutes to complete a single image, which is plenty of time for camera-shy proteins and viruses to scurry away, so those early pictures could have missed a lot of important details.
By 2001, researchers had miniaturized the scanning machinery and made other improvements to kick AFMs into high gear. Today’s high-speed AFMs can show us how nanobiology works in real time, capturing up to 50 frames per second! This allows scientists to film everything from DNA strands coming together to form the double helix, to cell membranes opening up to let in foreign invaders, to proteins folding up to change what they can do in your body.
And there’s more! Atomic force microscopy doesn’t just let us watch molecular processes happen live. It also lets us manipulate them. For example, you can stick the molecule of a drug onto the tip of the scanning probe, use the AFM to locate the receptor you want the molecule to interact with, plop it in, and see what happens. Scientists are using this technique to study how existing breast and prostate cancer drugs work, to get them to do their job even better.
So yeah, we’ve come a long way since Girolamo Fracastoro’s eyeglasses. But we’ve also come back around to creating a technology that lets us study teeny tiny things while they’re still kicking.
This SciShow video, that you’re probably watching thanks to cloud computing technology, is supported by Linode: a cloud computing company from Akamai. Linode provides access to some of your favorite internet services, from streaming videos to storing files. They keep it all running with data centers across the world, with the Akamai Global Network reaching over 4100 locations and 135 countries. By the end of 2023, they’re adding even more sites, so odds are good they’ve got a site that can work for you. If you want to make sure that Linode has your back in a remote area, you can run a speed test by connecting with one of Linode’s international facilities, all before any commitment. Then, you can get going with those brand new servers, by clicking the link in the description down below or heading to linode.com/scishow for a $100 60-day credit on a new Linode account.