Protocol | Published:

A modular approach to the design, fabrication, and characterization of muscle-powered biological machines

Nature Protocols volume 12, pages 519533 (2017) | Download Citation

Abstract

Biological machines consisting of cells and biomaterials have the potential to dynamically sense, process, respond, and adapt to environmental signals in real time. As a first step toward the realization of such machines, which will require biological actuators that can generate force and perform mechanical work, we have developed a method of manufacturing modular skeletal muscle actuators that can generate up to 1.7 mN (3.2 kPa) of passive tension force and 300 μN (0.56 kPa) of active tension force in response to external stimulation. Such millimeter-scale biological actuators can be coupled to a wide variety of 3D-printed skeletons to power complex output behaviors such as controllable locomotion. This article provides a comprehensive protocol for forward engineering of biological actuators and 3D-printed skeletons for any design application. 3D printing of the injection molds and skeletons requires 3 h, seeding the muscle actuators takes 2 h, and differentiating the muscle takes 7 d.

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Acknowledgements

We thank J. Sinn-Hanlon at the University of Illinois at Urbana-Champaign (UIUC) for image rendering of Figure 1a, and the Core Facilities at the Carl R. Woese Institute for Genomic Biology at the University of Illinois at Urbana-Champaign for assistance with sample preparation and imaging. We also thank V. Chan, P. Bajaj, S. Uzel, P. Sengupta, T. Saif, and R. Kamm for insightful discussions regarding this work. This work was funded by National Science Foundation (NSF) Science and Technology Center Emergent Behavior of Integrated Cellular Systems (EBICS) Grant CBET – 0939511. R.R. was funded by NSF Graduate Research Fellowship Grant DGE – 1144245. R.R. and C.C. were funded by an NSF Cellular and Molecular Mechanics and Bionanotechnology (CMMB) Integrative Graduate Education and Research Traineeship (IGERT) at UIUC (grant 0965918).

Author information

Affiliations

  1. Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA.

    • Ritu Raman
  2. Micro and Nanotechnology Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA.

    • Ritu Raman
    • , Caroline Cvetkovic
    •  & Rashid Bashir
  3. Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA.

    • Caroline Cvetkovic
    •  & Rashid Bashir
  4. Carle Illinois College of Medicine, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA.

    • Rashid Bashir

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Contributions

R.R. designed the modular muscle-ring protocol; R.R. performed and analyzed muscle seeding and functional assessment experiments; C.C. performed and analyzed muscle staining experiments and protein quantification experiments; R.R., C.C., and R.B. wrote the manuscript.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to Rashid Bashir.

Integrated supplementary information

Supplementary information

PDF files

  1. 1.

    Supplementary Text and Figures

    Supplementary Figures 1–4 and Supplementary Methods 1–3.

Zip files

  1. 1.

    Supplementary Data

    CAD files of muscle ring and muscle strip injection molds and symmetric and asymmetric one-ring, two-ring, and four-ring bio-bot skeletons; and FEA template file of one-ring bio-bot skeleton for computational modeling.

Videos

  1. 1.

    A modular approach to designing, fabricating, and controlling muscle-powered machines.

    Overview of major steps in protocol, including CAD design, 3D printing, muscle seeding, muscle differentiation, and bio-bot functional assessment.

  2. 2.

    Electrical stimulation of unconstrained muscle ring.

    Electrical stimulation (1 Hz) controls contraction in a muscle ring that is untethered to a bio-bot skeleton.

  3. 3.

    Directional locomotion in a bio-bot.

    Optical stimulation (4 Hz) drives directional locomotion of a one-leg asymmetric bio-bot in the direction of the longer pillar.

  4. 4.

    Rotational locomotion in a bio-bot.

    Optical stimulation (2 Hz) of one half of one muscle ring in a two-leg symmetric bio-bot drives rotational locomotion.

About this article

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DOI

https://doi.org/10.1038/nprot.2016.185

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