Under the microscope, the bacteria are oblong with built-in magnets that appear as dark blocks that line up like a spine.
Magnets in bacteria?
Brian Lower stumps a lot of people when he first mentions magnetic bacteria. So he’ll take out a pen and draw them. Or he might show a video of them moving about a screen, appearing as ants. When a magnet is placed nearby, they immediately align close to the magnet, like soldiers milling about then suddenly called into a lineup.
As intriguing as they may be to watch, magnetic bacteria also have potential for practical use to send cancer-fighting drugs to a particular part of the human body and to store a signficiant amount of data on a small chip.
“We would like to be able to control these guys in sophisticated ways,” says Lower, a biochemist and professor in the College of Food, Agricultural, and Environmental Sciences (CFAES).
Lower refers to the magnetic bacteria as “guys,” a casual term for his research subjects, probably because he’s been studying and working with them for the past decade. He knows them well. They spend time together. They’re just “guys” to him. And, besides, what else would you call these squiggles under a microscope? They’re magnetotactic bacteria, but you too might call them “guys” if your job, like Lower’s, were to make them interesting to college students, science majors and non-science majors alike.
Lower and his twin brother Steven, a microbiology professor in CFAES, with a joint appointment in the College of Arts and Sciences, are working with Ohio State physics professor Ratnasingham Sooryakumar, to study magnetic bacteria, having just received a National Science Foundation grant for $330,000.
In their three-year study, they will manipulate magnetic bacteria in three dimensions — up, down, left and right — and see the temperatures, oxygen levels and chemicals they can withstand — all of which could help determine how they can be useful in medicine, data storage and environmental cleanups.
The bacteria are much smaller than most organisms. About 1 million of them could fit into the period at the end of this sentence. One of them is smaller than a red blood cell; the magnets that it makes are the size of small viruses. Taking in iron from the environment, the organisms become tiny, moving magnets.
Magnetic bacteria come in all different shapes, but regardless of their differences, they can line up and huddle close, drawn by the force of a nearby magnet.
“You can use them as FedEx trucks to deliver goods from one point to another,” Lower said.
Those small goods could include blood cells, vaccines or pharmaceutical drugs. Under the right conditions, magnetic bacteria can act like a conveyor belt, 100 to 1,000 of them, all swimming together in a circle, potentially moving a substance from one end to another.
As part of the study, the Lower brothers and Sooryakumar will manipulate the magnetic bacteria to create microscopic robots. When the bacteria are controlled to move in unison as a group, they can assemble into living liquid-crystal displays, similar to the LCDs used in cell phones, televisions, instrument panels, cameras and smart watches.
The researchers also want to control how fast magnetic bacteria swim from one point to another, using their flagellum, the whip that hangs off one end, acting like a boat’s propeller to create a thrust forward.
By controlling the speed, movement and direction of the bacteria’s flagella, they will be able to construct extremely tiny micro-robots that can act as mixers, pumps and assemblers. While the development of these novel magnetic bacteria-powered-micro-machines is still in the research and development phase, their work offers a promising glimpse into the future of this emerging technology and the need for ever smaller mechanical or electronic gadgets.
In medicine too, magnetic bacteria could prove incredibly valuable.
Since the magnets that magnetic bacteria create can be heated to high temperatures, they can be sent out to target and kill cancer cells, possibly eliminating the need for chemotherapy. Initial experiments have thus far provided promising results eliminating cancer cells in mice, Lower said.
Magnetic bacteria could also help in environmental cleanups. An undergraduate student in CFAES is studying whether magnetic bacteria can draw phosphorous out of freshwater, like Lake Erie, thus reducing algal blooms.
With magnetic bacteria, very small magnets can be created. The smaller the magnet, the more data can be stored on a chip and the more precise an MRI (magnetic resonance imaging) can be.
Settling close to the sediments of rivers, lakes and the ocean, magnetic bacteria can be easily found, scooped up in a container, then examined under a microscope as they squirm toward a magnet.
The ease of finding magnetic bacteria and manipulating them under a microscope make them ideal for science classrooms. As part of the researchers’ study, they will provide outreach activities, including a summer workshop for teachers in Ohio, to train them on how magnetic bacteria could be introduced to their students.
What excites Lower most about magnetic bacteria is that they’ve been around awhile — hundreds of millions to perhaps billions of years.
“Studying them gives us a picture back in time of what life may have looked like back then,” he said.
Three years ago, Sooryakumar began working with the bacteria, and he continues to be intrigued by their potential partly because of how they move, and so quickly, coming together in swarms.
“If we can understand it, we can control it,’’ Sooryakumar said of their movement.
Calling them fast swimmers is an understatement. Magnetic bacteria can travel 10 to 20 times their body length in one second. That would be equivalent to a 5-foot tall person swimming 50 feet in the same amount of time.
“These are a highly evolved species,” Sooryakumar said. “We want to understand their dynamics, then we can use them.”