Development of a Magnetically-Actuated Capsule Robot for Biopsy Sampling Using SMA

Capsule Robots (CRs) with active locomotion improve on the inefficiency of passive locomotion in capsule endoscopes, showing great potential for clinical use. However, despite the development of various CR types, efficient locomotion and functional integration remain challenges due to space limitations and increasing demands. Additionally, many CRs are overly complex, so simplifying their structure while maintaining functionality is essential. This paper presents a novel magnetically actuated CR with two internal permanent magnets for oscillating locomotion and anchoring, along with a Shape Memory Alloy (SMA)-driven actuator for biopsy sampling. Compared to existing CRs, this design simplifies the structure while ensuring biopsy functionality and leaving space for a micro-CCD. The robot’s dynamics are modeled to guide its structural design and locomotion strategy. SMA characteristics are also examined to optimize the biopsy module’s parameters, improving efficiency and success rates. The CR undergoes experiments to assess safety, locomotion performance, and functionality, with results showing stable steering, and advantages in driving height, speed, and accuracy. Finally, the CR’s biopsy capabilities are validated in a gastric model and ex vivo stomach. This work offers a novel solution for gastrointestinal disease diagnosis and treatment, enhancing the application of CRs in biomedical engineering.