A soft-magnet-based drug-delivery module for active locomotive intestinal capsule endoscopy using an electromagnetic actuation system

• A soft-magnet-based drug delivery module was proposed for active locomotive intestinal capsule endoscope (ALICE).
• The drug-delivery module integrated in ALICE can actively release the drug at a specific target region.
• The drug-delivery module can execute its function without any energy consumption of the capsule endoscope.
• The proposed module has the drug loading capacity to 26% of total capsule.

Nowadays, capsule endoscope (CE) technology is highly evaluated as a promising medical apparatus for minimally invasive diagnosis and therapy. Active locomotive capsule endoscopy (ALICE) using an electromagnetic actuation (EMA) system is one of the new state-of-the-art solutions that effectively increase the diagnostic ability of CE. Together with a locomotive CE, there are various requests for multifunctional modules that can deliver drugs or execute biopsy functions. This paper presents a drug delivery module for ALICE using EMA, where we adopt a soft magnet due to its special physical properties. The drug-delivery module consists of two ring-type soft magnets and a simple plastic hinge; it has a volume of 0.78 ml, which is approximately 26% the total volume of a conventional active CE. The drug-delivery module can be integrated with ALICE. First, the drug is encapsulated into the module by the attracting force between two axially magnetized soft-magnetic rings. Second, ALICE with the drug delivery module can be driven by a precisely controlled external magnetic field to investigate and situate correct drug delivery to a target lesion. Third, at the target lesion, the external magnetic field is turned off and the two axial magnetized soft-magnetic rings of the drug-delivery module are demagnetized. Fourth, when we apply a strong pulsating magnetic field in a radial direction, the drug-delivery module is opened by the repulsive force between the two radially magnetized soft-magnetic rings, and the encapsulated drug can be released. After the drug release, the drug-delivery module can be returned to its initial shape thanks to an integrated plastic hinge in the drug delivery module and the attracting force between two axially magnetized soft-magnetic rings. Finally, the active CE can continue to show its intrinsic diagnostic work. Consequently, we demonstrate the feasibility of the drug-delivery module which is integrated in ALICE.