Synergy Actuation of Magnetic Catheter for On-site Biopsy Using Global and Local Magnetic Field

Applying magnetic force and torque is becoming a popular way to actuate and navigate microdevices in confined spaces, such as the vellum and gastrointestinal tract, for their high safety and reliability. A limitation of magnetic manipulation is the sharp decrease of manipulation force when the distance between the target and the magnetic source increases. To address this, we propose a synergy actuation strategy for controlling magnetic catheters by combining global and local magnetic fields. In this study, a permanent magnet and an array of coils are embedded at the end of a catheter. The embedded coils generate the local magnetic field to provide sufficient magnetic force. Moreover, the global field is generated by an external electromagnetic coil to steer the catheter through magnetic torque. The experimental results reveal the magnetic catheter can be steered to the target position in the bifurcated tract model. With a 0.3 A current input, the magnet can thrust from one end to the other end within 0.1 s. By attaching a sharp needle to the permanent, we demonstrate the biopsy capability of the magnetic catheter on various tissues with different moduli (i.e., adipose tissue and muscle tissue). This study provides a new solution to enhance the functionality of a catheter. © 2024 The Authors.