Science Robotics

Supplementary Materials

The PDF file includes:

  • Materials and Methods
  • Section S1. Materials of the microrobot
  • Section S2. Fabrication of the microrobot
  • Section S3. Actuation principles of the microrobot
  • Section S4. Control principle and optimal coil placement of the EMA system
  • Section S5. Characterization and calibration of the EMA system
  • Section S6. Experimental setup for microrobot targeting tests using the EMA system
  • Section S7. Experimental setup for fixation and adhesion tests of the microrobot
  • Section S8. Cell viability assay
  • Section S9. Evaluation of cell proliferation and loading of the microrobot
  • Section S10. Chondrogenic differentiation
  • Section S11. Reverse transcription polymerase chain reaction and real-time polymerase chain reaction
  • Section S12. Animals
  • Section S13. Evaluation of inflammatory responses to PLGA microscaffold and microrobot
  • Section S14. Histological and immunohistochemical analysis
  • Fig. S1. SEM images of PLGA microscaffolds after w-o-w emulsion–based gelatin leaching.
  • Fig. S2. PLGA microscaffold does not affect chondrogenic differentiation.
  • Fig. S3. Cartilage-specific gene expression gradually increases with the period of chondrogenic differentiation.
  • Fig. S4. Phantom with patella and medial condyle defect models for microrobot targeting test using a single magnet.
  • Fig. S5. Microrobot targeting with and without magnet at patella and medial condyle defect models.
  • Fig. S6. Experimental setup of EMA system and arthroscope for ex vivo targeting test on the porcine knee joint.
  • Fig. S7. Microrobot mobility in aqueous solution with different viscosity.
  • Fig. S8. Numerical simulation result of fluid flow by different directions of microrobot injection.
  • Fig. S9. Time-lapse image sequence of microrobots without magnetic targeting at the defect of medial condyle (left) and patella (right) in ex vivo porcine knee.
  • Fig. S10. A single magnet helps magnetic fixation of microrobot located at patella cartilage defects.
  • Fig. S11. Illustration and numerical simulation of microrobot fixation for medial condyle defects using the magnet placed on tibia.
  • Fig. S12. Numerical simulation results of magnetic field gradient generated from a magnet in defect region.
  • Fig. S13. Fluorescence image of engrafted hADMSC in cartilage tissue.
  • Fig. S14. Histological analysis of cartilage regeneration by microrobot system.
  • Fig. S15. Upper and lower regions of coil placement.
  • Fig. S16. First and last coil configurations among coil configuration candidates obtained through the optimization routine.
  • Fig. S17. Characterization and calibration of EMA system.
  • Fig. S18. Experimental setup for magnetic fixation of microrobot.
  • Table S1. Design parameters of the EMA system.
  • Table S2. Specifications of the EMA system with optimal coil configuration.
  • Table S3. Angle range of coils within the region of coil placement (fig. S15).
  • Table S4. Comparison between first and last coil configurations (fig. S16) for the coil configuration candidate obtained through the optimization routine.
  • Legends for movies S1 to S7
  • References (48–52)

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Other Supplementary Material for this manuscript includes the following:

  • Movie S1 (.mp4 format). Microrobot targeting with and without magnet at patella and medial condyle defect models.
  • Movie S2 (.mp4 format). Manipulation of microrobots in a knee joint phantom.
  • Movie S3 (.mp4 format). 3D magnetic targeting of microrobots in five phantoms with a hole.
  • Movie S4 (.mp4 format). Magnetic targeting of microrobots in ex vivo porcine knee cartilage at medial condyle and patella defects.
  • Movie S5 (.mp4 format). Magnetic fixation of microrobots in ex vivo porcine knee cartilage.
  • Movie S6 (.mp4 format). Adhesion of hADMSC-microrobots in ex vivo porcine knee cartilage.
  • Movie S7 (.mp4 format). Magnetic targeting of hADMSC-microrobots in rabbit knee cartilage with a medial condyle defect.

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