Exploiting the responses of magnetotactic bacteria robotic agents to enhance displacement control and swarm formation for drug delivery platforms

Magnetotactic bacteria MC-1 (MTB) synthesize a chain of magnetic nanoparticles called magnetosomes to navigate in deep-sea environments by orienting themselves in the direction of the Earth's magnetic field. MTB's inherent mobility and ability to be controlled by exposition to an external magnetic field has become of increasing interest for micromanipulation and drug transport applications. In the traditional control schemes, MTB were oriented by exposure to an external magnetic field causing them to align with the magnetic field lines. Directional changes were applied below a critical frequency and, as such, MTB were still able to swim along the generated magnetic field lines. The approach presented here proposes to apply to the MTB an oscillating magnetic field with a frequency beyond a critical limit to in order to exploit the time averaging magnetic field motion behavior of the bacteria cells. Results indicate that a time-multiplexed magnetic field made of various directional cycling fields can control the MTB more efficiently with less power, which is an advantage for future human-scale medical applications.