Control of a cell-cultured microrobot in vitro and in vivo. 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. Junyang Li et al. Sci. Robotics 2018;3:eaat8829 Copyright © 2018 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works