Dynamics of a microswimmer–microplatelet composite
Abdallah Daddi-Moussa-Ider, Maciej Lisicki, Hartmut Löwen, Andreas M. Menzel
Abstract
Guiding active microswimmers by external fields to requested target locations is a promising strategy to realize complex transport on the microscale. For this purpose, one possibility consists of attaching the microswimmers to orientable passive components. Accordingly, we analyze theoretically, using a minimal model, the dynamics of a microswimmer when rigidly attached to a (significantly larger) microplatelet, here represented by a thin circular disk. In this way, we first determine the flow field in the whole space induced by a Stokeslet that is located above the center of a spatially fixed rigid disk of no-slip surface conditions. Finally, we determine and analyze possible trajectories of the overall composite. To this end, the platelet is additionally endowed with a permanent magnetic moment, which allows us to steer the motion of the whole composite by a homogeneous external magnetic field. As previous experimental studies suggest, related setups may be helpful to guide sperm cells to requested targets or for the purpose of coordinated drug delivery.