Active and Adaptive: Reconfigurable Active Colloids with Internal Feedback and Communication Schemes

The vision of creating autonomous materials constituted of microscale motile units promises to disrupt a broad range of technologies but is still far beyond our reach.

Inspired by nature, these materials are active, i.e. they convert available energy into functions, and adaptive, i.e. they respond to stimuli by reconfiguring via internal feedback and signalling schemes.

In order to progress, we need to rethink the way in which we design, fabricate and control synthetic active units, aka active colloids or artificial microswimmers.

I propose an innovative approach that combines colloidal synthesis, assembly and actuation with nanofabrication and the implementation of feedback to realize a new class of active colloids.

Borrowing ideas from soft-robotic systems, we aim to realize and study “cyber-free” artificial microswimmers, which, in addition to on-board energy conversion, present internal degrees of freedom allowing for sensing, feedback and communication pathways ultimately to be regulated without external intervention.

In particular, we will: 1) Numerically and experimentally implement feedback schemes to regulate single-particle motility and collective behaviour based on control theory. 2) Use a unique combination of capillary assembly and two-photon nanolithography to create shape-shifting active colloids that autonomously regulate their motility based on stimuli orthogonal to their propulsion schemes. 3) Create “transmitting” and “receiving” active colloids, sending and sensing chemical signals (pH changes), to regulate their motility.

By introducing strong coupling between particles, and with stimuli beyond classical colloidal interactions, this proposal will enable a forward leap in the study of the emergent physics of active systems, as required to realize the vision of autonomous materials and microscale devices.