Rotating Multibarreled Capsule Robot for Multiple Biopsies and On-Demand Drug Delivery

Biopsy and drug delivery are critical functions performed by capsule robots to facilitate noninvasive diagnostic and therapeutic procedures for digestive tract diseases. In this study, we proposed a compact rotating multibarreled design for capsule robots that enables selective operation for either multiple biopsies or on-demand drug delivery. Each barrel can accommodate either a biopsy needle or a drug, providing flexibility to tailor the functions of the capsule robot to specific clinical needs. A motorized lead screw mechanism was employed to initiate the operations for tissue biopsy or drug release, while the transition between biopsy and drug delivery modes is facilitated by the motorized rotation of a cylinder that houses all the barrels. A robotic arm equipped with a permanent magnet as its end effector was used to achieve various motion controls for the capsule robot, including sliding, rolling, rotating, and pitching in different directions. Ex vivo experiments conducted in a porcine stomach demonstrated the successful sampling of human gastric tumors at three specific lesions, yielding an average sample volume of approximately 0.6 mm$^{3}$. Furthermore, we confirmed that the biopsy can penetrate the mucosal and submucosal layers of gastric tissue, allowing for tissue collection deep within the muscular layer. Additionally, the robot exhibited precise drug delivery capabilities, accurately administering multiple types of drugs to various lesions, achieving an average delivery rate of approximately 75% of the barrel's full capacity. The multifunctional and versatile design of the capsule robot presents great potential for advanced and tailored treatments in gastroenterology.