Scientists have created swimming micromotors that are powered by bacteria and light, and may be used for targetted drug delivery in the future. Researchers deposited a drop of fluid containing thousands of free-swimming, genetically engineered E coli onto an array of micromotors. This caused the micromotors to begin rotating within minutes. The bacteria swam the 15 microchambers etched on the outer edge of each micromotor. Their flagella protruding outside the microchambers caused the micromotors to rotate similar to how a flowing river rotates a watermill. “Our design combines a high rotational speed with an enormous reduction in fluctuation when compared to previous attempts based on wild-type bacteria and flat structures,” said Roberto Di Leonardo from the Sapienza Universita di Roma in Italy. “We can produce large arrays of independently controlled rotors that use light as the ultimate energy source,” said Di Leonardo, who led the study.
“These devices could serve one day as cheap and disposable actuators in microrobots for collecting and sorting individual cells inside miniaturized biomedical laboratories,” he said. The microchambers along the edges of each micromotor are tilted at an angle of 45 degrees, which maximizes the total force with which the bacteria can cause the motors to rotate, ‘Phys.org’ reported. In their design, the researchers also built a radial ramp with strategically placed barriers that direct the swimming bacteria into the microchambers.
The bacteria-propelled micromotors have potential medical applications, such as drug and cargo delivery, which the researchers plan to investigate in the future. The research was published in the journal Nature Communications.