Heterogeneously flagellated microswimmer behavior in viscous fluids

Abstract

An analysis of heterogeneously flagellated microswimmers inside viscous fluids is presented. Flagella harvested from Salmonella typhimurium were isolated, repolymerized, and functionalized to have biotin at their ends, allowing for chemical attachment along the surfaces of avidin-coated microparticles. Assembled microswimmers were rotated under incremental magnetic field frequencies, in saline and methylcellulose solutions, to baseline their velocity responses. A mean square displacement analysis revealed that rotating microswimmers exhibited anomalous diffusive behavior at small time scales in each fluid and had increased diffusivity compared with the non-rotating cases. Flagellated microswimmers had decreased diffusivity when compared with non-flagellated microparticles in Brownian conditions. Microswimmers were demonstrated to perform selected trajectories under proportional feedback control with reasonable accuracy. Finally, microswimmer propulsion was shown to be heavily influenced by the handedness of the rotating magnetic fields, with frequency induced reversals of swimming direction observed under clockwise rotation; this effect was determined to be the result of flagellar bundling and unbundling.

Artificial flexible sperm-like nanorobot based on self-assembly and its bidirectional propulsion in precessing magnetic fields

“…Thereon, sperm-shaped self-assembled nanorobots with modular designs stand out, which integrate a tiny head with a slender tail for flagellar construction, and can be treated as an optimal way for essential imitation of the sperms. For example, a Fe 3 O 4 microsphere could be connected with rigid Ni nanorod for sperm-shaped configuration, yet the desired flexibility and functionalization was lacked; or be linked with repolymerized bacterial flagellum to achieve flagellar propulsion, yet great diversity existed compared with the sperm’s shape 28 – 32 . Despite these tremendous efforts, to the best of our knowledge, no research has realized flexible sperm-like nanorobots with assembled head-to-tail structures.…”

Applications and Future Prospects of Micro/Nanorobots Utilizing Diverse Biological Carriers

“…Engineered bacteria and bacterial bionic materials are widely used in BMNRs. Rogowski LW et al [ 95 , 96 ] have developed a flagellar-propulsion-based nanoparticle, mimicking the flagella of Salmonella typhimurium . Cheng et al [ 30 ] designed a composite bacterial robot.…”

Mobile Microrobots for In Vitro Biomedical Applications: A Survey

“…By using two helices with opposing handedness connected by a rod, a frequency dependent velocity profile can be realized and used to drive each microrobot independently [43]. On the other hand, bioinspired microrobots take the advantage of the efficient bacterialike motion in fluids with low Reynolds number [44], [45], [46]. These microrobots include microorganism-like cilia or bacteria-like flagella fabricated with different magnetization directions to generate a preprogrammed motion using magnetic fields [47], [48].…”