Unveiling the Magnetic Marvels: Bacteria's Built-in Compass
Bacteria, the tiny microorganisms, are not just simple creatures; they are miniature navigators with a built-in compass that helps them find their way in the world. But here's where it gets fascinating: some bacteria have a magnetic twist! These bacteria, equipped with magnetic nanoparticles, can orient themselves using the Earth's magnetic field. This natural ability has caught the attention of researchers at the University of Basel, who are exploring the potential of these magnetic bacteria for various applications.
The research team, led by Argovia Professor Martino Poggio, delved into the world of magnetotactic bacteria, specifically Magnetospirillum gryphiswaldense. Inside this bacterium, a chain of magnetic nanoparticles, known as magnetosomes, acts as a biological compass. This compass helps the bacteria to navigate their environment, finding the best living conditions more efficiently.
But why is this important? Well, these bacteria could be the key to developing magnetically controllable microrobots for targeted drug delivery in medicine. They could also be used in wastewater treatment, where they absorb heavy metals and can be easily removed using a magnet. However, before we can fully harness this potential, we need to understand the magnetic properties of these bacteria in detail.
To achieve this, the researchers from the University of Basel collaborated with microbiologist Prof. Dirk Schüler from the University of Bayreuth. They focused on a single bacterium and its magnetic particles, which is a challenging task due to the weak magnetism of individual magnetosome chains. Most previous studies were limited to investigating ensembles of bacteria. But this team succeeded in measuring how the magnets within a single bacterium interact under an external magnetic field, and their findings were published in the journal Physical Review E.
Mathias Claus, the first author of the study and a doctoral student at the SNI PhD School, explains, "We attached a single bacterium to an extremely thin cantilever and measured its vibrations in magnetic fields. From tiny changes in the vibration frequency, we could infer the bacterium's magnetic strength and stability."
The team also conducted electron microscopy analyses and computer simulations, which confirmed that the magnetic strength of the chain is sufficient for the bacterium to align parallel to the Earth's magnetic field under natural conditions. However, they also found that very strong magnetic fields can disrupt this alignment, which is crucial for potential technical applications like controllable microrobots.
The bacteria in a lake, for instance, pose no risk. The Earth's magnetic field is not strong enough, and unlike the bacterium studied, they are not fixed to a cantilever. They simply continue to rotate until they are aligned with the magnetic field again. So, while this research opens up exciting possibilities, it also highlights the need for further exploration and understanding of these magnetic bacteria.
