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Shape-encoded dynamic assembly of mobile micromachines

Abstract

Field-directed and self-propelled colloidal assembly have been used to build micromachines capable of performing complex motions and functions. However, integrating heterogeneous components into micromachines with specified structure, dynamics and function is still challenging. Here, we describe the dynamic self-assembly of mobile micromachines with desired configurations through pre-programmed physical interactions between structural and motor units. The assembly is driven by dielectrophoretic interactions, encoded in the three-dimensional shape of the individual parts. Micromachines assembled from magnetic and self-propelled motor parts exhibit reconfigurable locomotion modes and additional rotational degrees of freedom that are not available to conventional monolithic microrobots. The versatility of this site-selective assembly strategy is demonstrated on different reconfigurable, hierarchical and three-dimensional micromachine assemblies. Our results demonstrate how shape-encoded assembly pathways enable programmable, reconfigurable mobile micromachines. We anticipate that the presented design principle will advance and inspire the development of more sophisticated, modular micromachines and their integration into multiscale hierarchical systems.

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Fig. 1: Spatial encoding of DEP attraction sites by modulating the 3D geometry.
Fig. 2: Reversible assembly of magnetic microactuators with a non-magnetic body using DEP forces.
Fig. 3: Shape-encoded assembly of magnetic microactuators to a non-magnetic body fabricated with direct laser writing.
Fig. 4: Shape-encoded reconfigurable assembly of micromachines with self-propelled microactuators for frequency-tunable locomotion.
Fig. 5: Hierarchical assembly of multiple micromachines via shape-encoded DEP interactions.
Fig. 6: 3D manipulation of microactuators and assembly of micromachines.

Data availability

Any data supporting the findings of this study are available within the Article and its Supplementary Information and are available from the corresponding author upon reasonable request.

Code availability

The open-source and commercial software used for data analyses are referenced in the Methods.

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Acknowledgements

The authors thank V. Liimatainen for helping with editing the manuscript. Y.A. thanks the Alexander von Humboldt Foundation for a Humboldt Postdoctoral Research Fellowship. A.F.D. acknowledges the Swiss National Science Foundation for the Scientific Exchange Grant no. IZSEZ0_181526. This work is funded by the Max Planck Society.

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Authors

Contributions

Y.A., B.Y. and M.S. conceived the idea and designed the research with contributions from O.B. M.S. supervised the overall research. Y.A., B.Y., O.B. and A.F.D. designed and performed the experiments, and analysed the data. Y.A. and B.Y. wrote the paper. All authors discussed the results, and revised or commented on the manuscript.

Corresponding author

Correspondence to Metin Sitti.

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The authors declare no competing interests.

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Supplementary information

Supplementary Information

Supplementary video legends 1–8, Supplementary Notes 1–3, Supplementary Figs. 1–14, Supplementary references.

Supplementary Video 1

Assembly and translation of a compound microvehicle with magnetic actuators.

Supplementary Video 2

Pick-and-place manipulation of non-magnetic objects using reversible assembly.

Supplementary Video 3

Tuning coupling stiffness of the assembly by modulating dielectrophoretic interactions.

Supplementary Video 4

Shape-encoded assembly of magnetic microactuators.

Supplementary Video 5

Shape-encoded assembly of self-propelled microactuators.

Supplementary Video 6

Reconfigurable mobile micromachines.

Supplementary Video 7

Hierarchical assembly of mobile micromachines.

Supplementary Video 8

Three-dimensional (3D) microactuator manipulation and assembly.

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Alapan, Y., Yigit, B., Beker, O. et al. Shape-encoded dynamic assembly of mobile micromachines. Nat. Mater. 18, 1244–1251 (2019). https://doi.org/10.1038/s41563-019-0407-3

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