Science & Technology

Robot swimmers show how microbes move

Robotic swimmers can help researchers better understand the movement of bacteria and other microbes.

Just by moving around, microorganisms such as bacteria and sperm have achieved amazing feats. The effect of viscosity is amplified on a small scale. In other words, the microbes that swim in the water are a bit like those who are trying to backstroke in the tar pit. Scientists still don’t have the complete picture of how they do it.

The new tool is Flagellum, An accessory like a cork bottle opener used by many microbes to avoid. By bringing its swimming action into the macroscopic world, this device makes it easy to study the fluid dynamics of the movement of the flagella. In addition, it is self-propelled, reconfigurable, and remote-controlled, allowing researchers to set up experiments that are not possible with real microorganisms.

Researchers hope that the insights generated by the device can help everything from fertility treatments to understanding how the infection spreads throughout the body.

“Microorganisms use incredibly complex forms of movement,” said a professor of engineering at Brown University. Scientific instrument review..

“We have mathematical models that approximate how it works, but to improve those approximations, we need to make detailed measurements of the velocity fields around these organisms. We would like to perform some of these measurements by creating a device that can mimic that swimming as much as possible. “

Zenit has been working on models of microbial swimming behavior for several years. Earlier, he developed a pill-sized device that included a magnet. It can be “swimmed” using a vibrating magnetic field.The device was a reasonable approximation of Bacterial swimmingBut Zenit wanted to improve it.

“Real bacteria don’t need a magnetic field because they have internal forces,” says Zenit. “I wanted to see if I could come up with a self-propelled one.”

So Zenit turned to Danielle Harris, an assistant professor of engineering who specializes in building custom devices for fluid dynamics research. Zenit and Harris thought that developing a robot prototype could be a good project for a group of Harris students.

Under Harris’s direction, a team of undergraduate students worked during the semester to devise a prototype of a robotic swimmer. One of the group, Matthew Styslinger, continued to work on the project as a Senior Capstone Project before graduating in 2021. From there, PhD student Asimanshu Das undertook the project, adding features and completing the design.

The device is based on the geometry of E. coli Bacteria. There is a cylindrical head about 6 centimeters (2.36 inches) long and 2 centimeters (0.787 inches) in diameter, created with a 3D printer. The waterproof head contains a small motor, power supply, and other electronic devices. The motor drives a helical tail created by a 3D printer about 9 centimeters (3.54 inches) long. You can swap the tails to experiment with different spiral angles and shapes. Adjust the speed and direction of rotation of the motor with the remote control.

The team ran a series of benchmark experiments using a device that swims in a mixture of corn syrup and water. This is close to the viscosity of a microscale swimmer that only plows water. The results showed that the swimming performance of the device was in line with the predictions of a simple resistance model. This is the same theory that is often applied to streamline the movement of microscopic counterparts on devices.

After verifying the device, the team is currently planning various experiments to shed new light on the spiral swim.

“This gives us the ability to perform macroscopic experiments that we have full control over,” says Harris. “Imagine trying to instruct a bacterium to swim in a particular direction or change direction. Spiral angle.. It’s pretty difficult to do that. But that’s what you can do. “

In the future, the team will measure the flow field around the swimmer in detail. They light up some important questions that remain unanswered, such as what happens to the flow when microorganisms encounter hard walls, or how the flow changes when multiple organisms swim together. I hope to guess.

Source: Brown University

Robot swimmers show how microbes move Robot swimmers show how microbes move

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