Robocoliths : An Engineered Coccolith-Based Hybrid that Transforms Light into Swarming Motion

The establishment of controlled nano- and mesoscopic energized entities that gather, in a concerted effort, into motile aggregated patterns is at the forefront of scientific discovery. However, translating energy into swarming motion for such miniature-based entities remains a challenge. This requires simultaneously breaking the symmetry of the system to enable locomotion and a coupling effect between the objects that are part of the population to induce the collective motion. Herein, we introduce Robocoliths as a new concept of light-driven Emiliania huxleyi (EHUX) coccolith-based miniature entities capable of swarming behavior. EHUX coccoliths are characterized by an asymmetric morphology, which is a crucial advantage in the design of nano- and mesoscopic objects with locomotory abilities. Their activation with the bioinspired material polydopamine not only endowed the asymmetric coccoliths with advanced functionalities such as thermal and energy harvesting responsiveness under visible light exposure; it also provided a functional surface from which antifouling polymer brushes were grown. The energy harvesting responsive Robocoliths can induce an increase of temperature in the surrounding environment while displaying a collective behavior (i.e., swarming) via a controlled ON-OFF light switching mechanism. In this context, Robocoliths could pave the way for a new generation of multifunctional swarming bio-micromachines with a potential impact in various fields of applications, starting from the analytical and environmental sectors and extending to the therapeutically relevant domains.