Petersen Instruments Part 2 - The Magnetodrome
At a similar time as the VFTB my dad and me started working on the Bacteriodrome as shown below, or later, the Magnetodrome. These instruments have two application areas.
In biomagnetism magnetotactic bacteria are organisms that navigate based on the earth’s magnetic field. They do this in lakes and lake sediments to find nutrients located in certain areas at the bottom of a lake. This navigation is possible because the bacteria have small magnetite particles built-in that act as a sensor for the environment magnetic field.
To explore the behavior of these magnetotactic bacteria, one of most prominent is the Magnetobacterium Bavaricum, it makes sense to generate magnetic fields of variable strength and direction. A typical example is a rotating field that makes the bacteria move in a circle. Using image processing the trace of this rotation can be plotted and used for characterization of the magnetotactic organism. My father discovered the first Magnetobacterium Bavaricum in lake Chiemsee in Bavaria, Southern Germany.
The image below shows an example of the bacteriodrome plotting the traces of magnetic bacteria swimming in a rotating magnetic field. These images are created by adding the difference between two intensity thresholded adjancent video frames.
The more modern version of the bacteriodrome is the magnetodrome. Instead of the simple Helmholtz coils of the original design the system uses powerful electromagnets to move magnetotactic bacteria, but also other magnetic samples such as environmental particles or even nano-robots. One can think of the magnetometer as a set of magnetic tweezers to manipulate magnetic particles of all kinds.
As with the VFTB my primary work on the magnetodrome was the development of its control software. While overall the control of the system was a lot less complex than the VFTB, the key part here was the image processing of the camera stream from the microscope. While at some point we ported all image processing to work with OpenCV and Nvidia CUDA in high resolution, we initially used digitizers and video processing libraries by Matrox that had started working in this field back in the 1970’s.
Similarly to the work on the VFTB, Mag-Instruments has done a fantastic job modernizing the magnetodrome with a redesign of the mechnical design of the system as well as the control and image processing software. The photo below shows this re-newed version.
