image: Illustration of the mechanical design and workflow of the macabot. (a) Schematic of a multichamber capsule robot with four single-chamber capsules with decoupled opening directions. (b) Photograph of the fabricated macabot. (c) Schematic of macabot navigating in the digestive tract by oral administration. (d) Schematic of macabot rolling navigation in (i) the stomach and (ii) the intestine. (e) Schematic of the macabot sampling liquid and releasing the drug by opening the magnetic valve.
Credit: Parts of Figure c and d were produced using images from Smart Servier Medical Art (CC BY 4.0).
While ingestible capsule endoscopes have revolutionized digestive tract diagnosis, current capsule devices are still difficult to combine diagnostic functions (targeted biopsy) and therapeutic functions (targeted drug delivery) in one-time oral intake. Now, research has broken through this limitation by presenting a novel multichamber magnetic capsule robot (named macabot) that can selectively open specific chambers on demand for targeted liquid sampling or targeted drug release.
The capsule robot features multiple independent chambers, each equipped with a specially designed magnetic valve. The key innovation lies in the fact that these valves' activations are only sensitive to magnetic forces from specific directions. By applying magnetic fields with different directions of gradients, a target chamber can be opened selectively—like using different keys for different locks—while others remain securely closed. In addition, this "selective opening" function would not be influenced by the magnetic torque, allowing the rotating magnetic field to drive the capsule rolling to the target site. In addition, the robot employs a modular design, allowing the number of chambers to be flexibly adjusted as demand requires.
"It's like the robot is equipped with multiple independently controllable switches," explained co-corresponding author Prof. Qingsong Xu. "The medical doctor could direct the robot rolling to a target site, then 'command' a single chamber to open for sampling the bodily fluid, and later 'command' another chamber to release drugs at the same site or a different site. These operations can be completed after a single oral intake, which significantly enhances the comfort and efficiency of diagnosis and treatment."
Furthermore, the research team successfully validated the robot's functionality in ex vivo porcine stomach models. Under the guidance of real-time ultrasound imaging, the robot can precisely navigate to target sites. Furthermore, the robot performed liquid sampling and drug release at different sites. The team also demonstrated the in situ generation of a shape-adaptive hydrogel drug patch at the target site by storing the polymer and crosslinker in different chambers. This offers a new strategy for sustained drug release.
"Our work provides an integrated platform for the precise diagnosis and treatment of gastrointestinal diseases, which is a significant direction for the development of minimally invasive medical devices," said another co-corresponding author, Prof. Yang Lu. "It not only reduces the discomfort associated with multiple procedures for patients. But also, thanks to its multichamber design, it supports some instances involving combination drug therapy and multiple lesion sites."
The researchers believe that this multifunctional capsule robot holds substantial potential for clinical applications, paving the way for a new approach to diagnosing and treating gastrointestinal diseases, such as inflammatory bowel disease.
The research is published in the journal National Science Review. Dr. Zehao Wu from the University of Macau is the first author. Prof. Qingsong Xu from the University of Macau and Prof. Yang Lu from The University of Hong Kong are the co-corresponding authors of this paper.
Journal
National Science Review