How to Construct Machines as Small as Cells
If you want to build a fully functional nanosized robot, you need to incorporate a host of capabilities, from complicated electronic circuits and photovoltaics to sensors and antennas. But just as importantly, if you want your robot to move, you need it to be able to bend.
Cornell researchers have created micron-sized shape memory actuators that enable atomically thin two-dimensional materials to fold themselves into 3D configurations. All they require is a quick jolt of voltage. And once the material is bent, it holds its shape – even after the voltage is removed. As a demonstration, the team created what is potentially the world’s smallest self-folding origami bird. And it’s not a lark.
The group’s paper, “Micrometer-Sized Electrically Programmable Shape Memory Actuators for Low-Power Microrobotics,” published in Science Robotics and was featured on the cover. The paper’s lead author is postdoctoral researcher Qingkun Liu. The project is led by Itai Cohen, professor of physics, and Paul McEuen, the John A. Newman Professor of Physical Science, both in the College of Arts and Sciences.
“We humans, our defining characteristic is we’ve learned how to build complex systems and machines at human scales, and at enormous scales as well,” said McEuen. “But what we haven’t learned how to do is build machines at tiny scales. And this is a step in that basic, fundamental evolution in what humans can do, of learning how to construct machines that are as small as cells.”
McEuen and Cohen’s ongoing collaboration has so far generated a throng of nanoscale machines and components, each seemingly faster, smarter and more elegant than the last.
“We want to have robots that are microscopic but have brains on board. So that means you need to have appendages that are driven by complementary metal-oxide-semiconductor (CMOS) transistors, basically a computer chip on a robot that’s 100 microns on a side,” Cohen said.
Imagine a million fabricated microscopic robots releasing from a wafer that fold themselves into shape, crawl free and go about their tasks, even assembling into more complicated structures. That’s the vision.