Dynamic structural transformation of self-assembled Janus hydrogel microparticles under periodically-changed magnetic field

This paper describes self-assembly of Janus hydrogel microparticles, which enables to transform the assembled structures dynamically. Using a centrifuge-based microfluidic device, we fabricated Janus hydrogel microparticles encapsulating superparamagnetic materials in one side to respond to magnetic field. We succeeded in dynamic construction of structures using hydrogel microparticles and in acquiring three different self-assembled structures (two different pearl chain structures and close packing structures) that can transform to other structures dynamically by controlling precessional magnetic field for the first time. We believe that our system will be an effective platform for dynamic cell cultivation system, for organizing biomimetic autonomous microrobots, and for understanding self-organization and complex systems observed in nature.