Magnetic Response of Magnetospirillum Gryphiswaldense

TL;DR

This study models and experimentally verifies the magnetic response and U-turn trajectories of Magnetospirillum Gryphiswaldense bacteria under rotating magnetic fields, confirming the theoretical model with precise measurements.

Contribution

It presents a validated physical model for bacterial magnetic response based on rotational drag and magnetic torque, supported by detailed microfluidic experiments.

Findings

Confirmed the model's accuracy within measurement error

Measured average rotation rate of bacteria as 0.74 ± 0.03 rad/mTs

Demonstrated bacteria's U-turn behavior under varying magnetic fields

Abstract

In this study we modelled and measured the U-turn trajectories of individual magnetotactic bacteria under the application of rotating magnetic fields, ranging in ampitude from 1 to 12 mT. The model is based on the balance between rotational drag and magnetic torque. For accurate verification of this model, bacteria were observed inside 5 m tall microfluidic channels, so that they remained in focus during the entire trajectory. From the analysis of hundreds of trajectories and accurate measurements of bacteria and magnetosome chain dimensions, we confirmed that the model is correct within measurement error. The resulting average rate of rotation of Magnetospirillum Gryphiswaldense is 0.74 +- 0.03 rad/mTs.