Designing Oscillation Using Magnetic Handshake Materials

One fascinating feature of living materials is their ability to change morphology and oscillate between different states. With oscillation, structures can perform tasks such as run and tumble locomotion or cargo delivery. Maintaining oscillation between more than two states, however, can be difficult and requires pathways for the structure to intake energy. Here, we show how to achieve such multi-state oscillation in self-assembling structures made up of Magnetic Handshake Material building blocks. Our strategy entails assembling structures that retain net magnetic dipole moments so that we can directly control the structure's motion using an external magnetic field. By inverse designing the interactions between the Magnetic Handshake building blocks and the external field, we are able to obtain multi-state oscillation cycles in structures assembled from heterogeneous magnetic clusters. These results demonstrate proof of concept designs for self-assembling microscopic magnetically actuatable machines.