3D printed active starships and other nonuniaxial swimmers

Microorganisms exhibit autonomous locomotion through complex media and can react to changes in their environment. Leptospira bacteria, for example, swim towards regions of high viscosity [1]. This ability of bacteria and living cells to adapt their motion in response to external stimuli is called taxis [2]. While different kinds of taxis have been studied, most notably chemotaxis, the mechanism behind viscotaxis was not investigated until recently. Liebchen et al. found that swimmers with nonuniaxial body shapes swim up viscosity gradients due to the generation of asymmetric viscous torques acting on different parts of the swimmer [3]. We are testing these theoretical predictions using artificial microswimmers created by 3D printing based on two-photon lithography that gives us access to virtually any shape. We have started with the fabrication of trimers on the micrometre scale, the simplest form of a nonuniaxial body shape, but we are also exploring the motion of other nonuniaxial swimmers such as starships.

1) M. G. Petrino et al., J. Gen. Microbiol., 1978, 109, 113-117.
2) D. B. Dusenbery, Living at Micro Scale, Harvard University Press, 2009.
3) B. Liebchen et al., Phys. Rev. Lett., 2018, 120, 208002.