Selective Motion Control of a Novel Magnetic-Driven Minirobot With Targeted Drug Sustained-Release Function

In this article, we propose a novel magnetic-actuated multimodule drug sustained-release minirobot (DSM) manipulated by an external rotating electromagnetic field. The structure of the DSM is mainly divided into three parts: 1) a shell; 2) an internal propeller; and 3) a drug chamber. The shell can effectively protect the intestinal tract and reduce the various resistances during the work; the built-in propeller not only realizes active locomotion but also saves internal space, which provides the feasibility for the development of functional modules of the robot. The drug chamber pushes the carried drugs out of the chamber similar to a syringe. With structural optimization, we have realized the sustained-release and quantitative drug delivery based on the characteristics of minimagnets’ individual starting frequency- and pitch-related calculations. The main challenge to achieve these functions is to manipulate two magnets in the same magnetic field to drive different functional modules, without mutual interference between the two magnets. In this article, a series of simulations and experiments are conducted to evaluate DSM's motion performance, drug delivery function, and dose control during drug delivery. In the experiment, two different drug delivery points were set up to make DSM spray the drug on the fester areas twice respectively. Finally, an
in vitro
experiment using the DSM prototype was executed with fresh pig large intestine in a curved shape pipe mold.