Realization of the Najafi-Golestanian microswimmer

The development of artificial microswimmers, microscopic robots that swim in a fluid like sperm cells and
motile bacteria, could cause a leap forward in various fields such as microfluidics, microsystems, or minimally
invasive medicine. Nature provides plenty of examples of efficient microswimmers. However, a bottom-up
approach, looking at the simplest ingredients needed to generate a microswimmer, can lead to a deeper under-
standing of the swimming problem. First described by Najafi and Golestanian 1 , a paradigmatic microswimmer
is the three-linked-spheres model, which follows a minimalist approach for propulsion by shape shifting. In this
presentation, we describe the experimental realisation of this microswimmer using self-assembled ferromagnetic
particle at an air-water interface, powered by an uniform oscillating magnetic field 2 . A model, using two har-
monic oscillators, reproduces the experimental findings. Because the model remains general, the same approach
could be used to design a variety of efficient microswimmers.