fig3

Figure 3. Soft robotic microtools designed for use in vivo. (A) Untethered acoustically driven bubble bots controlled by ultrasound into a mouse brain^[53]; (B) Untethered magnetically driven targeted drug delivery devices that are propelled by gastric acid^[20]; (C) Tethered stiff-soft photothermal microgripper at the tip of an optical fiber controlled by a light polymerized gel that can swell or shrink either due to temperature or pH^[146]. [Images (A-C) are licensed under CC BY 4.0. http://creativecommons.org/licenses/by/4.0/.]