Microscopic artificial swimmers.
Microorganisms such as bacteria and many eukaryotic cells propel themselves with hair-like structures known as flagella, which can exhibit a variety of structures and movement patterns. For example, bacterial flagella are helically shaped and driven at their bases by a reversible rotary engine, which rotates the attached flagellum to give a motion similar to that of a corkscrew. In contrast, eukaryotic cells use flagella that resemble elastic rods and exhibit a beating motion: internally generated stresses give rise to a series of bends that propagate towards the tip. In contrast to this variety of swimming strategies encountered in nature, a controlled swimming motion of artificial micrometre-sized structures has not yet been realized. Here we show that a linear chain of colloidal magnetic particles linked by DNA and attached to a red blood cell can act as a flexible artificial flagellum. The filament aligns with an external uniform magnetic field and is readily actuated by oscillating a transverse field. We find that the actuation induces a beating pattern that propels the structure, and that the external fields can be adjusted to control the velocity and the direction of motion.
Dreyfus
Rémi
R
Laboratoire Colloïdes et Matériaux Divisés, ESPCI, UMR CNRS 7612 UPMC, ParisTech, 10 rue Vauquelin, 75005 Paris, France. remi.dreyfus@espci.fr
Baudry
Jean
J
Roper
Marcus L
ML
Fermigier
Marc
M
Stone
Howard A
HA
Bibette
Jérôme
J
D040761:Biomimetic Materials / Q000737:chemistry* / Q000378:metabolism*; D019921:Biotinylation; D003102:Colloids / Q000737:chemistry; D004247:DNA / Q000737:chemistry; D004912:Erythrocytes / Q000737:chemistry; D005407:Flagella / Q000502:physiology*; D006801:Humans; D008280:Magnetics; D009038:Motion; D018583:Pliability; D019809:Streptavidin
D003102:Colloids; D004247:DNA; D019809:Streptavidin