A team of researchers at Cornell University has created a new class of magnetically controlled microscopic robots (microbots) that operate at the diffraction limit of visible light. These microbots, called diffractive robots, can interact with visible light waves and yet move independently, allowing them to move to specific locations, take images, and measure forces at the scale of the body’s smallest structures. You can.
Diffractive robotics connects untethered robots with imaging techniques that rely on visible light diffraction (the bending of light waves as they pass through an aperture or around something).
Imaging techniques require an aperture with a size comparable to the wavelength of light.
For the optics to work, the robot must be at that scale, and for the robot to reach the target it is imaging, it must be able to move on its own.
The robot is controlled by a magnet that performs a pinching motion, allowing it to move inchworm-like across solid surfaces. The same motion can also be used to “swim” through a fluid.
The combination of maneuverability, flexibility, and sub-diffractive optical technology represents a major advance in the field of robotics.
“A walking robot that is small enough to interact with light and effectively shape it would place a microscope lens directly into the microworld,” said Paul McEwen, a professor at Cornell University.
“We can perform close-up imaging in a way that would never be possible with a regular microscope.”
“These robots are 2 to 5 microns in size. They're tiny. And by controlling the magnetic fields that drive their movement, we can make them do whatever we want them to do.”
“I'm really excited about the fusion of microrobotics and micro-optics,” said Dr. Francesco Monticone of Cornell University.
“The miniaturization of robotics has finally reached a stage where these actuated mechanical systems can interact with and actively shape light on the scale of just a few wavelengths (one millionth of a meter). I did.”
To magnetically drive a robot at this scale, the research team used hundreds of nanometer-scale magnets with two different shapes, long and thin or short and stubby, with the same volume of material to drive the robot. I made it into a pattern.
Professor Itai Cohen of Cornell University says, “Long, thin objects require a larger magnetic field to switch from pointing in one direction to pointing in another direction, whereas short, stubby objects require a larger magnetic field to switch from pointing in one direction to pointing in another direction.'' “Things require smaller magnetic fields.”
“So if you apply a large magnetic field, you can align them all, but if you apply a smaller field, only the short and thick ones will flip.”
To create the robot, the authors combined this principle with a very thin film.
“One of the main challenges for optical engineering was to find the best approach for the three tasks (light conditioning, focusing, and super-resolution imaging) for this particular platform, because “different approaches “There are different performance trade-offs depending on how the microrobots behave,” said Dr. Monticone. “They can move and change shape.”
“There are advantages to being able to mechanically move the diffractive elements to enhance imaging,” Professor Cohen says.
The robot itself can be used as a diffractive grader or a diffractive lens can be added. In this way, the robot can act as a local extension of the microscope lens looking down from above.
The robot measures force using the same magnet-driven pinching motions used to push structures while walking.
“These robots are very compliant springs, so if something pushes on them, it can squeeze them,” Professor Cohen said.
“That changes the diffraction pattern and allows us to measure it very well.”
Force measurements and optical capabilities can be applied to basic research such as exploring the structure of DNA. Or it may be introduced into clinical practice.
“Looking to the future, we can imagine swarms of diffractive microbots walking along the surface of samples to perform super-resolution microscopy and other sensing tasks,” Professor Monticone said.
“I think we have just scratched the surface of what is possible with this new paradigm of combining robotics and optics at the microscale.”
of study Published in a magazine science.
_____
Conrad L. Smart others. 2024. Magnetically programmed diffractive robotics. science 386 (6725): 1031-1037;doi: 10.1126/science.adr2177
Source: www.sci.news
