Tiny robots swimming through our bodies zapping polyps or delivering drugs has been the stuff of future tech hype for decades. But even as this concept becomes closer to reality (albeit slowly), one of many big questions is: How do you steer the micromachines? North Carolina State University recently demonstrated a technique to make their microbots do U-turns. From New Scientist:
The microbot, a mere 1.3 millimetres long, is essentially a diode – an electrical element that only allows current to pass in one direction. The diode is exposed to an alternating electric field, which induces a voltage across it, creating an electric dipole. This dipole pushes on ions in the water, driving them backward and propelling the microbot forward.
In order to make the bot turn, the group added a DC element to the field, modifying the initial AC field. Rachita Sharma and Orlin Velev believe that the DC field changes the distribution of the ions near the diode, and the torque they exert on the electric dipole causes the microbot to rotate. Once the microbot completed its 180-degree turn, the researchers turned off the DC field, and the microbot swam off in the other direction.
"Microbots made to twist and turn as they swim"
