Robotic surgery is no longer the stuff of science fiction. However, these robots can't really feel their way around -- the need for super-small mechanisms rules out existing approaches to touch. That's where Harvard researchers might come to save the day. They've developed a pop-up sensor whose four layers collapse to a tiny footprint (just a tenth of an inch) when necessary, but expand into a 3D sensor thanks to a built-in spring. The design is extremely sensitive, too, with a light intensity sensor that can detected mere millinewtons of force.
The technology is a ways off from reaching robotic surgeons, and the current goal is to make the sensor both smaller and tougher. However, the existing hardware is already small enough to fit into the minuscule catheter you see below, and it's cheap to manufacture thanks to a process where the devices effectively build themselves. It might not be long before machines can perform operations that require a delicate touch, such as applying a small amount of pressure to a wound.
[Image credits: Joshua Gafford/Harvard SEA]