Performance evaluation of magnetically driven cytology brush applicable to capsule endoscopy

This article provides a novel magnetic actuator suitable for brush cytology using capsule endoscopy. Its space-saving mechanism consisting of a brush-tipped elastic wire coupled with a rotatable permanent magnet can be easily assembled in a swallowable capsule. When external magnetic fields are applied, the brush projects outwards with rotation of the magnet, and then collects cells from gastrointestinal tract. The distinctive feature of the proposed actuator is that it can perform four different actuations including projection/pullback/scrape modes for the brush and a rotation mode for the capsule body. Each actuation mode can be selected by the direction of the external magnetic fields. This study has verified that each mode can exhibit the desired performance and determined its driving conditions. Furthermore, an additional small magnet attached to the brush tip has been found to enhance the performance of the scrape mode. The results obtained in this study suggested that the proposed actuator should be a hopeful candidate for cytological diagnosis with capsule endoscopy.