Researchers from the Sapienza University of Rome have created 3D printed micromotors that can be powered by E.coli bacteria.
The group created micromotors using a custom-built two photon polymerization setup and were able to autonomously capture and harness the swimming bacteria. Two photon polymerization is a type of stereolithography and involves the use of a laser to cure materials into intricate 3D structures.
Gif shows the micromotors propelling with the bacteria. Images via Nature Communications.
Using E. coli, the researchers could propel the “biological propellers” using light. This process was enabled by genetically modifying the E. coli to exploit proteorhodopsin. This protein is light-driven and the research explains they were able to activate the bacteria by using different intensities of light.
The researcher team, led by physics professor Roberto Di Leonardo, built the micromotors to have specially engineered ramp chambers for the bacteria. The bacteria is contained in 45 degree microchambers and propelled to turn the motors at maximum torque. Leonardo explains this 45 degree angle was essential,
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. We can produce large arrays of independently controlled rotors that use light as the ultimate energy source.
With the special design of the micromotors and the modified bacteria, the research was able to successfully control the speed of the propellers in unison.
Gif shows close-up of the swimming E. coli at work. Images via Nature Communications.
Applying the propellers
The propelled micromotors have potential application in medical devices as we’ve seen with other research. German researchers similarly implemented a 3D printed structure and harness sperm to fight gynecologic cancers.
Leonardo explains the 3D structures his team have created “could serve one day as cheap and disposable actuators in microrobots for collecting and sorting individual cells inside miniaturized biomedical laboratories.”
The technology could also be implemented in drug delivery as another German study has explored with 3D printed microswimmers. On a more commercial scale, 3D printed bacteria has been explored for its viability in creating advanced sportswear in a study by MIT, the National University of Singapore and New Balance.
Featured image shows figure 1 from the paper showing the features of the 3D printed micromotors. Image via Nature Communications.