A Magnetically-Triggered Soft Capsule for On-Demand Mucus Collection

Abstract

In this work, we present a soft capsule for mucus collection in human intestine for diagnostic purpose, with reduced risk of tissue damage compared with other biopsy methods. The capsule implements passive locomotion and the sampling process is triggered by magnetic field using a permanent magnet, which is placed on the skin above the region of interest (ROI). The capsule contains a soft vacuum chamber which is sealed with wax. When magnetic field and mucus are present simultaneously, the circuit inside the capsule will be closed and nichrome wire will start to generate heat to melt the wax, and mucus will be collected into the vacuum chamber due to air pressure. Experiments on heating capability of nichrome wire, mucus collection and reliability of the capsule are conducted to validate this design. Fig. 1. (a) The conceptual working scenario of the soft capsule for ondemand mucus collection. It consists of a permanent magnet that sticks on patient's skin and a soft capsule for mucus collection. (b) Schematics of all the components inside the capsule. arXiv:1809.03096v1 [physics.med-ph]

Smart capsules for sensing and sampling the gut: status, challenges and prospects

“…(C) A magnetic capsule with a hinge mechanism to collect digesta and microbiota sample with blind activation based on predicted transit time (reproduced from Shokrollahi et al 152 2021 IEEE). (D) A flexible capsule triggered with a magnet to collect the surrounding fluid with suction (reproduced from Du et al 150 2018 IEEE). (E) A commercial prototype with sophisticated external magnetic control mechanism to drag the capsule to the target-site and on-board camera to visualise the collection site (reproduced from Ding et al 151 ).…”

“…Once the capsule reached the target-site, the sampling process was activated by magnetic actuation via a reed switch and a nichrome wire surrounding the inlet of chamber was heated so it melted the wax and allowed the collection of fluid via vacuum suction. 150 This design did not consider resealing the inlet to avoid cross-contamination. A commercial company NaviCam (AnX Robotica, USA) has developed a magnetically controlled sampling capsule endoscope that can be manoeuvred to the target-site and its orientation can be precisely controlled using an external magnetic field.…”

Sensing Mucus Physiological Property In Situ by Wireless Millimeter‐Scale Soft Robots

“…GI tract endoscope-based procedures such as endoscopic retrograde cholangiopancreatography (ERCP) [16] or colonoscopy [17] cannot access the small intestine and upper colon easily and can potentially cause trauma and other complications for patients under anesthesia. [18,19] In addition, passive capsule devices [20][21][22][23] and mobile capsule endoscope robots [24][25][26][27][28][29] have been developed to collect and sense biofluids in the GI tract, [30,31] which are typically at the centimeter scale and can only access the space with comparable size of the capsule in the GI tract. [32] Moreover, further in vitro testing of the properties of the collected mucus sample using fluorescence microscopes and other tools [33] may not accurately reflect the mucus properties as they depend on the environment humidity and temperature.…”

Development of a Robotic Capsule for in vivo Sampling of Gut Microbiota

“…3) The development and extensive testing of sealing mechanism to withstand the entire gut environment and also protect the collected sample from cross contamination which is essential for in-vivo trials and was not achieved before by state of the art sampling devices [16], [17], [24].…”