“…At present, untethered microrobots have achieved remarkable achievements in minimally invasive surgery [ 1 , 2 ], drug delivery [ 3 – 5 ], environmental remediation [ 6 – 8 ], and tissue engineering [ 9 , 10 ]. These microrobots can be actuated wirelessly by external energy such as magnetic field [ 3 , 11 , 12 ], light [ 13 – 15 ], ultrasound [ 16 , 17 ], chemical reaction [ 18 – 20 ], electric field [ 21 ], etc.…”