Design of a Magnetic Dual-Needle Biopsy Capsule Robot Resilient to Cross-Infection and Mixed Contamination

Abstract

Capsule robots have demonstrated great potential for comfortable, non-invasive diagnosis of the gastrointestinal tract. With the advancement of research in capsule endoscopy, its functionality has expanded from initial imaging capabilities to include biopsy operations. However, most biopsy capsule robots cannot separately place the tissues obtained during biopsy. The cross-infection caused while using the same biopsy tools at different biopsy sites, and inaccurate results due to mixed contamination of the pathological tissues, still need to be addressed. This paper presents a novel magnetic Dual-needle Biopsy Capsule Robot (DBCR) design to solve this problem. The capsule design was simplified into a double needle switching and anchoring structure in the capsule, modelled based on a retractable pen’s extension and retraction control mechanism. Additionally, the design was equipped with magnets and springs of different sizes to complete the needle switching mechanism and extract the tissue samples. The force of the external control magnet on the magnet inside the capsule was simulated to determine the control distance to achieve different functions and ensure sampling reliability. The prototype was designed, manufactured, and tested using in vitro experiments. The achieved results show that the proposed design of the DBCR is promising and can potentially obtain biopsy samples, preventing cross-infection and mixed contamination.Note to Practitioners— The proposed DBCR design can potentially address the limitations of current systems in obtaining biopsy samples, mainly by preventing cross-infection and mixed contamination, in double-needle designs. The proposed design offers a dual-needle storage and switching mechanism based on a retractable pen-inspired linear-to-rotational motion conversion system for compartmentalized sampling and the gradient magnetic field control of embedded magnets and springs to ensure needle activation only during biopsy. Thus, the proposed design finds its suitability for use in biopsy.