Development and Experimental Evaluation of an Endoscopic Capsule Robot Equipped With a Fail-safe Biopsy Mechanism

Endoscopic capsule robots (ECRs) have introduced feasible and painless gastrointestinal diagnostics to endoscopic procedures. To further enhance the capability of these revolutionary devices, many research groups have attempted to equip ECRs with functions such as active locomotion, drug delivery, and biopsy. This study addresses the challenges related to the biopsy functionality of ECRs by introducing a remote biopsy mechanism adapted from the magnetic spring concept. The mechanism consists of one axial permanent magnet (PM) fixed inside the ECR's body, a radial PM free to translate along the device length and rotate perpendicular to its magnetization direction, and conventional biopsy forceps. The presented ECR can locomote directly using external gradient magnetic fields or through rotation via external uniform magnetic fields. Additionally, the proposed biopsy mechanism ensures reliable actuation and a fail-safe design. To evaluate the performance of this design, a prototype with a diameter of 12 mm and a length of 30 mm was fabricated, and its functionality in active rotational locomotion, orientation control, and biopsy actuation was demonstrated through experiments.