Max Planck Institute for Intelligent Systems researchers are now a step closer to using microrobots for medical tasks, creating microscallops that are small enough for use in bodily fluids but still strong and smart enough to navigate through said bodily fluids.
Technology is nowhere near shrinking a team and shipping them off to perform surgery from within. But Peer Fischer, head of the Micro, Nano, and Molecular Systems Research Group at the Planck Institute, and colleagues were able to develop little helpers that can accurately head to certain targets in the body, making certain procedures as minimally invasive as possible or even taking away the need for surgery completely.
To get to this point, the research team led by Fischer had to address two challenges. First was the matter of size -- they had to make sure their robot is small enough. And second, once inside the body, the robot had to be able to move through tissues and bodily fluids.
Working with researchers from the Technical University in Dortmund and Technion in Israel, Fischer and colleagues came up with an artificial scallop with a diameter measuring just a few hundred micrometers. They were able to easily scale down a robot to meet the size requirements they had in mind, but they ran into a problem with the scallop's shell as bodily fluids had so much friction. With so much resistance, the shell's movements were simply cancelled out.
According to Fischer, the microscallop's shell was just a few times bigger when compared with how thick one strand of human hair was. At that size, water will feel as viscous as honey, maybe even closer to what tar would feel like for people.
"Most bodily fluids have the property that their viscosity changes depending on the speed of movement. But as soon as something moves through this fluid, the molecular mesh breaks apart and the fluid becomes less viscous," explained Fischer.
Following this idea, researchers then turned to controlling the scallop's shell in such a way that it opens faster than it closes. The asymmetrical movement this creates makes the fluid less viscous, allowing the microscallop to move. To control a microscallop's shell, it is fitted with rare-earth magnets.
What's next?
After testing microscallop movement in other bodily fluids, Fischer's team is interested in finding out if microscallops can move through tissues.
The study was published in the journal Nature Communications.
