Research ArticleMEDICAL ROBOTS

Development of a magnetic microrobot for carrying and delivering targeted cells

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Science Robotics  27 Jun 2018:
Vol. 3, Issue 19, eaat8829
DOI: 10.1126/scirobotics.aat8829
  • Fig. 1 Design and fabrication of magnetic microrobots.

    (A) Images of the designed burr-like porous spherical microrobot before and after cell seeding. (B) Fabrication procedures of the microrobots including writing, developing, Ni/Ti deposition, and cell culture process. (C) SEM images of a burr-like microrobot cultured with MC3T3-E1 cells and MSCs for 12 hours. The laser power and scan speed of photoresist were set at 25 mW and 250 μm/s, respectively.

  • Fig. 2 Simulation results of magnetic driving ability in hepatic artery, portal vein, and hepatic vein.

    (A) Velocity fields of a cubic structure. (B) Velocity fields of a burr-like spherical structure. (C) Surface area–to–viscous resistance ratios of the two microrobot structures.

  • Fig. 3 Microrobots with different cell-carrying capacities under different grid lengths (lg) and burr lengths (lb).

    (A) SEM images and statistical results of cell-cultured microrobots when lg = 0.8rc, rc, 1.2rc, 1.4rc, 1.6rc, 1.8rc, where rc is the mean radius of carried cells (n = 3). (B) SEM images and statistical results of cell-cultured microrobots when lb = 0, 0.5rc, rc , 1.5rc, 2rc, 3rc (n = 3). Error bars indicate SD.

  • Fig. 4 Cell viability tests.

    SEM images of (A) MC3T3-E1 cells and (B) MSCs on days 1, 3, and 5 of culture. (C) Survival rates of MC3T3-E1 cells and MSCs in culture at 1, 3, and 5 days after PI staining. (D) Histogram representing the average viability of cells cultured for 1, 3, and 5 days (n = 3). Error bars indicate SD.

  • Fig. 5 Control of a cell-cultured microrobot in vitro and in vivo.

    (A) Movement of a microrobot cultured with MC3T3-E1 cells along a desired rectangular path in clockwise direction in PBS. (B) Velocity of MC3T3-E1 cell–cultured microrobot against the magnetic field gradient in different fluid environments (n = 4). (C) Position errors of the MC3T3-E1 cell–cultured microrobot in different fluid environments (with a magnetic field gradient of 4 to 9 T/m). (D) Time-lapsed images of the MSC-cultured microrobot moving in the yolk of a zebrafish embryo. (E) Velocity of MSC-cultured microrobot against the magnetic field gradient in vivo (n = 4). (F) Positional errors of the MSC-cultured microrobot in vivo (with a magnetic field gradient of 20 T/m). Error bars indicate SD.

  • Fig. 6 In vitro cell-release experiments on a glass substrate.

    (A) MC3T3-E1 cells were released from the microrobot onto a pure glass substrate and proliferated at 3 days of cultivation. (B) MSCs transferred from the microrobot onto the glass substrate with precultured C2C12 cells at 7 days of cultivation.

  • Fig. 7 In vitro cell-release experiments in a microfluidic chip.

    (A) Schematic of the cell-releasing process. (B) Results of the transendothelial migration of cells.

  • Fig. 8 In vivo cell-release experiments on nude mice.

    (A) In vivo fluorescence imaging of a swarm of microrobots. The microrobots with HeLa GFP+ cells were injected into the left dorsum of the nude mice. The microrobots not carrying any cells were injected into the right dorsum of the nude mice. White arrows represent the position of the injection. (B) Two different hematoxylin-eosin–stained sections of HeLa tumor with the injected microrobots. The positions of the microrobots are marked by the red dashed lines.

Supplementary Materials

  • robotics.sciencemag.org/cgi/content/full/3/19/eaat8829/DC1

    Text

    Fig. S1. Energy-dispersive spectrometry spectra.

    Fig. S2. Prototype of the magnetically actuated micromanipulation system consists of fixed DT4E-core identical electromagnetic coils.

    Fig. S3. Insertion of the cell-cultured microrobot into the zebrafish embryo for in vivo transportation experiments.

    Fig. S4. Velocities of the cell-cultured microrobot in different medium under different magnetic field gradients.

    Fig. S5. A self-constructed microprobe platform for microoperation.

    Table S1. The Reynolds numbers and related environmental parameters.

    Movie S1. Design and fabrication of cell-cultured microrobot.

    Movie S2. Transportation of cell-cultured microrobot in vitro and in the yolk of zebrafish embryo.

    Movie S3. Cells releasing experiments in vitro and in nude mice.

  • Supplementary Materials

    Supplementary Material for:

    Development of a magnetic microrobot for carrying and delivering targeted cells

    Junyang Li, Xiaojian Li, Tao Luo, Ran Wang, Chichi Liu, Shuxun Chen, Dongfang Li, Jianbo Yue, Shuk-han Cheng, D. Sun*

    *Corresponding author. Email: medsun{at}cityu.edu.hk

    Published 27 June 2018, Sci. Robot. 3, eaat8829 (2018)
    DOI: 10.1126/scirobotics.aat8829

    This PDF file includes:

    • Text
    • Fig. S1. Energy-dispersive spectrometry spectra.
    • Fig. S2. Prototype of the magnetically actuated micromanipulation system consists of fixed DT4E-core identical electromagnetic coils.
    • Fig. S3. Insertion of the cell-cultured microrobot into the zebrafish embryo for in vivo transportation experiments.
    • Fig. S4. Velocities of the cell-cultured microrobot in different medium under different magnetic field gradients.
    • Fig. S5. A self-constructed microprobe platform for microoperation.
    • Table S1. The Reynolds numbers and related environmental parameters.

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    Other Supplementary Material for this manuscript includes the following:

    • Movie S1 (.mp4 format). Design and fabrication of cell-cultured microrobot.
    • Movie S2 (.mp4 format). Transportation of cell-cultured microrobot in vitro and in the yolk of zebrafish embryo.
    • Movie S3 (.mp4 format). Cells releasing experiments in vitro and in nude mice.

    Files in this Data Supplement:

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