Friction, forces, shears: the game changes when robots get tiny. Marc Miskin brings you to scale on these up-and-coming microrobots and nanorobots for biotechnology. Listen and learn How the rules of physics adjust when the application of robotics goes small, How these factors bring interesting challenges surrounding loss of inertia and other aspects of robot locomotion, and What biomimicry this research entails such as nano flagella and cilia.  Marc Miskin is an assistant professor of Electrical and Systems Engineering at the University of Pennsylvania and works in a robotic systems lab. He's working on nano machines that may one day soon explore our bodies for medical purposes. The robots are so small that they aren't visible to the eye—think approximately hair width. This field has taken the advances in small computers to small robots, around 70 to 100 microns in size. The forces at this scale are different, of course, and bring in some interesting challenges. When they get tinier, friction, adhesion, and viscosity become the dominant effects and mass takes second stage. Those dominant traits become more important as the area-to-volume ratio becomes large. "It's like everything in your universe is flypaper," he says. What's really interesting is that the electrical aspects remain constant. The voltages and currents are still fixed and electrical interference isn't an issue. The way they move, to swim or propel, also becomes very different than larger human-sized organisms—they can't rely on mass to keep the momentum going. They use silicon, wires, and metal so that, unlike with biological organisms, they can play around with such materials to address these challenges. However, he assures listeners, these materials fall under "generally recognized as safe," and are low toxicity. Elasticity is also an issue these materials hope to address. They need to create enough movement over a small size that can also be controlled by a signal with a specific voltage size, about 1. They came up with something they call "circuit electric chemical actuators," which basically chemically bonds through electron rearranging to create a force. He explains more interesting challenges in this tiny production model and addresses applications for these microbots in real life, though they are still in proof of concept. They imagine utilizing them when single-cell precision is desired, as with nerve work.  For more about this work, see his lab's website: seas.upenn.edu/~mmiskin. Available on Apple Podcasts: apple.co/2Os0my