Flagellated Magnetic Particle Swimming*

Swimming bacteria have been the main inspiration behind development of microscale robots for drug delivery applications. Many bacteria, like Salmonella typhimurium, swim by rotating and bundling helical flagella extremities, allowing them to propagate on the microscale. The flagellin proteins which makeup the flagellum are highly dynamic materials, which can not only self-assemble, but also optimize their helical forms in response to physical and chemical property changes within the surrounding fluidic environment. Harvesting bacterial flagella and chemically bonding them to rigid magnetic particles allows for simplistic and reliable bottom up manufacturing to create environmentally responsive microswimmers. In this work, we present research into biohybrid flagellated magnetic particles for microswimmer applications. Flagellated magnetic particles of different diameters are actuated using rotating magnetic fields. The pH of the fluid environment is adjusted to compare different helical forms and their effects on swimming motion. Finally, we examine how multiflagellated particles swim in comparison to their living bacterial counterparts. These microswimmers are promising for diagnosing and treating diseases in a minimally invasive manner.