Article

Untethered micro-robotic coding of three-dimensional material composition

  • Nature Communications 5, Article number: 3124 (2014)
  • doi:10.1038/ncomms4124
  • Download Citation
Received:
Accepted:
Published online:

Abstract

Complex functional materials with three-dimensional micro- or nano-scale dynamic compositional features are prevalent in nature. However, the generation of three-dimensional functional materials composed of both soft and rigid microstructures, each programmed by shape and composition, is still an unsolved challenge. Here we describe a method to code complex materials in three-dimensions with tunable structural, morphological and chemical features using an untethered magnetic micro-robot remotely controlled by magnetic fields. This strategy allows the micro-robot to be introduced to arbitrary microfluidic environments for remote two- and three-dimensional manipulation. We demonstrate the coding of soft hydrogels, rigid copper bars, polystyrene beads and silicon chiplets into three-dimensional heterogeneous structures. We also use coded microstructures for bottom-up tissue engineering by generating cell-encapsulating constructs.

Additional access options:

Already a subscriber?  Log in  now or  Register  for online access.

References

  1. 1.

    , & Bioprinting: functional droplet networks. Nat. Mater. 12, 478–479 (2013).

  2. 2.

    , & A tissue-like printed material. Science 340, 48–52 (2013).

  3. 3.

    , , & Colour-barcoded magnetic microparticles for multiplexed bioassays. Nat. Mater. 9, 745–749 (2010).

  4. 4.

    et al. Programming magnetic anisotropy in polymeric microactuators. Nat. Mater. 10, 747–752 (2011).

  5. 5.

    et al. 3D printing of interdigitated Li-ion microbattery architectures. Adv. Mater. 25, 4539–4543 (2013).

  6. 6.

    et al. 3D printed bionic ears. Nano. Lett. 13, 2634–2639 (2013).

  7. 7.

    & Bioprinting for stem cell research. Trends Biotechnol. 31, 10–19 (2013).

  8. 8.

    et al. Simple precision creation of digitally specified, spatially heterogeneous, engineered tissue architectures. Adv. Mater. 25, 1192–1198 (2013).

  9. 9.

    , , , & Emerging technologies for assembly of microscale hydrogels. Adv. Healthc. Mater. 1, 149–158 (2012).

  10. 10.

    , , , & Guided and fluidic self-assembly of microstructures using railed microfluidic channels. Nat. Mater. 7, 581–587 (2008).

  11. 11.

    , & Three-dimensional fluidic self-assembly by axis translation of two-dimensionally fabricated microcomponents in railed microfluidics. Small 7, 796–803 (2011).

  12. 12.

    et al. The assembly of cell-encapsulating microscale hydrogels using acoustic waves. Biomaterials 32, 7847–7855 (2011).

  13. 13.

    et al. Three-dimensional magnetic assembly of microscale hydrogels. Adv. Mater. 23, 4254–4260 (2011).

  14. 14.

    et al. Paramagnetic levitational assembly of hydrogels. Adv. Mater. 25, 1137–1143 (2013).

  15. 15.

    , , & Directed assembly of cell-laden microgels for fabrication of 3D tissue constructs. Proc. Natl Acad. Sci. USA 105, 9522–9527 (2008).

  16. 16.

    , , & Hydrogel microrobots actuated by optically generated vapour bubbles. Lab. Chip 12, 3821–3826 (2012).

  17. 17.

    , & Micro-assembly using optically controlled bubble microrobots. Appl. Phys. Lett. 99, 094103 (2011).

  18. 18.

    et al. Modeling, control and experimental characterization of microbiorobots. Int. J. Robot. Res. 30, 647–658 (2011).

  19. 19.

    , & Modeling and experimental characterization of an untethered magnetic micro-robot. Int. J. Robot. Res. 28, 1077–1094 (2009).

  20. 20.

    et al. Flow induces a motile and aggressive phenotype in 3D ovarian cancer nodules via increased EMT, activated EGFR and decreased E-cadherin. Proc. Natl Acad. Sci. 110, 1974–1983 (2013).

  21. 21.

    , , & Manipulating biological agents and cells in micro-scale volumes for applications in medicine. Chem. Soc. Rev. 42, 5788–5808 (2013).

  22. 22.

    , , & Two-dimensional autonomous microparticle manipulation strategies for magnetic microrobots in fluidic environments. IEEE Trans. Robot. 28, 467–477 (2012).

  23. 23.

    , & Remotely addressable magnetic composite micropumps. RSC Adv. 2, 3850–3856 (2012).

  24. 24.

    , & Independent control of multiple magnetic microrobots in three dimensions. Int. J. Robot. Res. 32, 614–631 (2013).

  25. 25.

    , , & Control of multiple heterogeneous magnetic microrobots in two dimensions on nonspecialized surfaces. IEEE Trans. Robot. 28, 172–182 (2012).

  26. 26.

    The principle of close packing and the condition of thermodynamic stability of organic crystals. Acta Crystallogr. 18, 585–590 (1965).

  27. 27.

    & Net shape fabrication of stainless steel–alumina composite micro parts. J. Micromech. Microeng. 19, 045018 (2009).

  28. 28.

    , , & Assembly and disassembly of magnetic mobile micro-robots towards deterministic 2-D reconfigurable micro-systems. Int. J. Robot. Res. 30, 1667–1680 (2011).

Download references

Acknowledgements

We thank H.I. Gungordu for her help in MTT assays and S. Chung, X. Dong and J. Giltinan for their help in preparing magnetic micro-robot experiments. U.D. acknowledges that this material is based in part on work supported by the National Science Foundation under NSF CAREER Award Number 1150733, NIH R21HL112114 and NIH R01EB015776-01A1. M.S. and E.D. were partially supported by the National Science Foundation under NSF-NRI Award Number 1317477. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Science Foundation. U.D. is a founder of, and has an equity interest in, DxNow Inc., a company that is developing microfluidic and imaging technologies for point-of-care diagnostic solutions. U.D.’s interests were reviewed and are managed by the Brigham and Women’s Hospital and Partners HealthCare in accordance with their conflict of interest policies.

Author information

Author notes

    • S. Tasoglu
    •  & E. Diller

    These authors contributed equally to this work

Affiliations

  1. Bio-Acoustic MEMS in Medicine (BAMM) Laboratory, Division of Biomedical Engineering, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA

    • S. Tasoglu
    • , S. Guven
    •  & U. Demirci
  2. Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA

    • E. Diller
    •  & M. Sitti
  3. Harvard-MIT Health Sciences and Technology, Cambridge, Massachusetts 02139, USA

    • U. Demirci

Authors

  1. Search for S. Tasoglu in:

  2. Search for E. Diller in:

  3. Search for S. Guven in:

  4. Search for M. Sitti in:

  5. Search for U. Demirci in:

Contributions

U.D., M.S. and S.T. developed the idea. S.T. and E.D. designed the experiments. E.D., S.T. and S.G. performed the experiments. S.T., E.D., U.D. and M.S. wrote the manuscript. All authors edited the manuscript.

Competing interests

The authors declare competing financial interests in the form of a pending provisional patent (BWH case no 22548, filed on 11/18/13, Robotic-assembly of hydrogels).

Corresponding authors

Correspondence to M. Sitti or U. Demirci.

Supplementary information

PDF files

  1. 1.

    Supplementary Figures, Table, Notes and References

    Supplementary Figures 1-2, Supplementary Table 1, Supplementary Notes 1-2 and Supplementary References

Videos

  1. 1.

    Supplementary Movie 1

    Two-dimensional micro-robotic coding and reconfiguration of PEG hydrogels with various shapes into complex planar constructs. Scale bar is 1 mm.

  2. 2.

    Supplementary Movie 2

    Two-dimensional micro-robotic coding of material composition. Square hydrogels were surrounded by bracket-shape hydrogels. Scale bar is 1 mm.

  3. 3.

    Supplementary Movie 3

    Orientation and position control in untethered micro-robotic coding of material composition. “Tetris”-shaped PEG hydrogels were assembled in a rectangular reservoir. Scale bar is 1 mm.

  4. 4.

    Supplementary Movie 4

    Three-dimensional micro-robotic coding of a heterogeneous structure consisting of PEG microgels which totally encase 100 μm diameter copper cylinders and 200 μm diameter polystyrene spheres. The experiment was performed in a 20 mm x 20 mm x 4 mm chamber in PBS. Scale bar is 1 mm.

Comments

By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.