Directed Navigation of Magnetotactic Bacteria via Magnetotaxis in a 3D Vasculature‐On‐A‐Chip

Abstract Magnetotactic bacteria (MTB), inherently motile and self‐powered, are promising biorobotic candidates for targeted anti‐cancer drug delivery since they can actively deliver the therapeutic agent to the tumor, decreasing adverse side effects. However, the directed navigation of these bacteria through intricate microenvironments mimicking the natural microvasculature has not been investigated. Here, the directed navigation of MTB is demonstrated within a vasculature‐on‐a‐chip platform. A perfusable vascular network is developed to investigate MTB at the single‐microorganism level. MTB is demonstrated to successfully align and navigate along the magnetic field inside the microvessels. Surface interaction with the microvessel walls, hydrodynamic forces, and counterdirectional flows in the order of 10 µm∙s −1 are examined as potential factors that may interfere with the MTB alignment and magnetotaxis. The average swimming speed of the studied bacteria within the vasculature‐on‐a‐chip device is 13.9 µm s −1 . Finite Element Analysis reveals that under these conditions, MTB experience shear stresses of up to 30 Pa, and drag forces between 10 and 40 pN, depending on their relative orientation to the flow field. Altogether, this work provides a first demonstration of effective directed navigation of MTB in a vasculature‐on‐a‐chip platform, and the influence of external factors on their field alignment and magnetotactic behavior.