Supplementary Information

Supplementary Table 1 and Protocol 1

Supplementary Video 1

Real-time video of DMD hiPSC-derived 3D skeletal muscle construct contractions in response to 10-V electrical stimulation at 1 Hz

Supplementary Video 2

Calcium transients in DMD hiPSC-derived 3D artificial muscles incubated with the fluorescence Ca 2+ indicator Fluo-4AM upon electrical stimulation. During the first 10 s, no electrical stimuli were applied to the muscle. At second 10, the 3D muscle was stimulated with 10 V at 0.33 Hz, and at second 20, the 3D muscle was stimulated with 20 V at 0.33 Hz

Supplementary Video 3

Maximum-intensity projection time-lapse video of 5-chloromethylfluorescein diacetate (CMFDA)-stained HIDEMs (green) deposited on hiPSC-derived 3D muscles (red). 100-µm stacks of muscles were imaged every 12 min for 4 h by using a spinning disk microscope. Scale bar, 100 µm

Supplementary Video 4

3D reconstruction of a 3D artificial muscle imaged with a light-sheet microscope immunostained as detailed in the advanced imaging section of Fig. 2

Supplementary Video 5

3D reconstruction nuclear morphology (lamin A/C in red) and myotubes (eMyHC in green) of a healthy control hiPSC-derived 3D muscle construct shown in Fig. 3. The 3D reconstruction was done by using Imaris software and confocal z-stacks of immunostained artificial muscles. Video reproduced from ref. 29 under Creative Commons license CC BY 4.0

Supplementary Video 6

3D reconstruction nuclear morphology (lamin A/C in red) and myotubes (eMyHC in green) of an LMNA-mutant (R249W) hiPSC-derived 3D muscle construct shown in Fig. 3. The 3D reconstruction was done by using Imaris software and confocal z-stacks of immunostained artificial muscles. Video reproduced from ref. 29 under Creative Commons license CC BY 4.0