Researchers at Cornell University have created tiny robots the size of cells that are powered and steered using ultrasound waves. The movement of the tiny robots was inspired by how bacteria and sperm move. Researchers believe the tiny robots could eventually become a new tool for delivering drugs directly to affected cells and tissues.
The study lead author is Tao Luo, who works in the laboratory of Professor Mingming Wu in the Cornell College of Agriculture and Life Sciences. For more than ten years, the professor’s laboratory has studied how various microorganisms move and communicate within their environment. The ultimate goal of that study was to create a remotely controlled robot able to navigate inside the human body.
Bacteria are highly specialized to their environments and can swim ten times the length of the body in one second. Sperm can swim against the flow of liquid. The team knew they could not build their tiny robots to run on battery power because the batteries would be too heavy, making the robots unable to swim. The team settled on high-frequency sound waves.
High-frequency sound waves were chosen because ultrasound is silent and is easy to use in the laboratory. The technology is also safe to use on the human body, according to the FDA. Initial attempts to produce robots using photolithography resulted in unusable robots. The team created functional and usable robots when the university purchased a new laser lithography system called NanoScribe.
That system can create 3D nanostructures by writing directly in a photosensitive resin. With the new technology, researchers could modify designs on a micrometer scale and create new iterations for testing quickly. Over six months, the team was able to build a triangular micro-robotic object that could swim. It also has cavities etched in its back that captures an air bubble creating motion when an ultrasound transducer is aimed at the robot. Future challenges for the researchers include making the robot biocompatible, allowing them to be used within the body.