Functional integration and payload transportation with MR-LF. White arrows indicate crawling direction. (A,B) Side-view image compositions of MR-LF bidirectional locomotion in a rigid confined channel (ID: 19 mm) with (A) electronics in its rigid compartment, and (B) as conjoined robots demonstrating that after ingestion, multiple MR-LFs could be assembled and actuated. (C,D) Side-view image sequences of drug delivery with a modified MR-LF and a modified MR-LF-S in a compliant, thin-walled tube (ID: 16 mm, wall thickness: 0.05 mm). Both robots descend into the water (36 °C) and deliver blue dye to simulate drug delivery, then climb back out of the water on a slope (θ = 8°). For remote drug delivery (C), the MR-LF has a perforated compartment containing a dye-filled dissolvable capsule. For catheter tip navigation (D), the soft MR-LF-S compartment is cast around flexible tubing to demonstrate MR-LF-S with an internal lumen being used to guide continuum devices such as catheters and endoscopes. (E,F) Top-view illustrations (left) and angled view images (right) show bidirectional robot locomotion and turning in confined channels (ID: 19 mm). Arrows in illustrations show the trajectory of the robot. In (E), the robot moves through a 180° bend, and in (F) the robot moves through a bifurcation with an angle of 30°. Scale bars: 10 mm.