A Stanford University team has created the amphibious all-terrain vehicle of the drug delivery world. The researchers designed the millimeter-scale robot to roll, flip and spin past obstacles and through liquids to navigate complex biomedical environments.
Multiple papers have described the creation of wirelessly operated millimeter-scale origami robots that can move through narrow spaces and change shape to complete specific tasks. Potential applications for the robots include targeted drug delivery, in which context the vehicles would carry a payload for release at a specific site.
The Stanford research, details of which were published in Nature Communications, builds on the earlier work, notably by enabling on-ground and in-water locomotion. Operated magnetically, the millirobot is designed to adapt itself to the environment, autonomously switching between rolling and flipping to get over some obstacles. Applying a magnetic field causes the millirobot to jump over bigger barriers.
Using the device, the Stanford team delivered a liquid therapy to a target in the stomach of a pig ex vivo. The millirobot rolled and flipped along a predetermined path through the stomach. Once at the target site, magnetic pumping enabled the release of the payload.
The researchers added a spinning mechanism to enable the millirobot to swim under and on the surface of water. To provide early validation of the spinning mechanism, the team navigated the device through an ex vivo pig stomach with viscous fluid. The viscous fluid provided more resistance than water, but that was overcome by increasing the strength of the magnetic field.
Having generated early evidence of what the device is capable of, Renee Zhao and her collaborators are now talking to their counterparts at Stanford’s medicine department about ways to use the technology.