Researchers at TU Delft have found that E. coli bacteria can coordinate their movements, establishing order in what appears to be random biological systems. By confining individual bacteria in micro-engineered circular cavities and connecting these cavities via narrow channels, the team observed synchronized bacterial movement.
Their findings, which hold significant promise for advancing the design of controllable biological oscillator networks, were recently published in the esteemed journal Small.
Synchronization is a captivating natural phenomenon that can be seen in a variety of contexts, from an audience clapping in unison to fireflies illuminating the night in harmony or even flocks of starlings moving flawlessly together.
First described by the brilliant Christiaan Huygens in the 17th century, synchronization is famously illustrated by his pendulum clocks swinging in perfect alignment.
Now, researchers at TU Delft have revealed that even E. coli bacteria – tiny single-celled organisms measuring only a few micrometers in length – can exhibit this same behavior.
“This was a remarkable moment for our team,” said Farbod Alijani, associate professor at the Faculty of Mechanical Engineering. “Seeing bacteria’ dance in sync’ not only showcases the beauty of nature but also deepens our understanding of the microscopic origins of self-organization among the smallest living organisms.”
In the study, Alijani’s team, collaborating with TU Delft professor Cees Dekker and the innovative TU Delft spin-off SoundCell, has harnessed the power of precisely engineered microcavities to isolate single E. coli cells from large populations. Inside these unique circular cavities, the bacteria exhibited mesmerizing rotary motion akin to pendulum clocks. By connecting two of these cavities with an intricate channel, the researchers observed an exciting phenomenon: the two bacteria began to synchronize their movements over time.
“This synchronization occurs because of hydrodynamic interactions induced by the movement of bacteria in the coupled system,” explains Alijani. The team quantified this coupling strength and found that the bacteria’s coordinated motion adhered to universal mathematical rules of synchronization.
This finding opens up a world of possibilities for the design of micro-tools that can induce tailored oscillations and synchronization in bacterial systems, offering scientists a novel way to explore bacterial motility and coordination in confined spaces.
Now, the team is venturing into more complex realms by interlinking multiple cavities to create expansive networks of synchronized bacteria. “We want to uncover how these networks behave and whether we can engineer even more sophisticated dynamical movements,” Alijani adds.
Although this research is mainly foundational, its potential applications are wide-ranging. “This could even provide a novel approach to drug screening, for instance, by measuring fluid flow changes and forces caused by bacterial movement before and after administering antibiotics,” Alijani suggests.
The inspiration for this study stems from an earlier achievement where Alijani’s team captured the first-ever sound emitted by a single bacterium using a graphene drum.
“We were curious if we could go a step further and create order out of the chaotic oscillations we observed,” says Alijani. With this study, they’ve moved from recording the soundtrack of a single bacterium to orchestrating their ‘tango.’
Journal reference:
- Aleksandre Japaridze, Victor Struijk, Kushal Swamy, Ireneusz Rosło´n, Oriel Shoshani,Cees Dekker, and Farbod Alijani. Synchronization of E. coli Bacteria Moving in CoupledMicrowells. Small, 2024; DOI: 10.1002/smll.202407832