Adaptive microswimmer navigation via surface interactions.

Colloidal swimmers are prominent candidates for numerous applications, e.g. in biomedicine, where they could deliver drugs at specific locations within complex environments, i.e. in the presence of confining geometries. Microswimmers typically tend to self-propel parallel to surfaces (1), which for the case of 3D-printed microstructures causes swimmer capture along one-dimensional paths. Along those paths, swimmers exhibit a plethora of cooperative behaviors, i.e. enhanced propulsion speed, motion at preferred distances in self-assembled trains and even compact chains with rich dynamics, depending on path morphology and swimmer directionality (2). Those activity-induced interactions have opened the door towards increasing motion efficiency. Yet, most colloidal swimmers still only have limited adaptability to navigate within confinements, which hinders their applicability. To overcome this, we are currently investigating the emergence of adaptive motility in self-assembled binary colloidal swimmer systems that reconfigure upon encountering surfaces under an ac field.