Magnetically Guided Capsule for High-Capacity Dual Sampling of Gut Microbiome

This study proposes a novel dual-sampling capsule for gut microbiome sampling that maximizes storage capacity while maintaining a simple and efficient design. The capsule utilizes an external magnetic handler with a permanent magnet to control sampling operations. The magnetic interaction between the capsule and the handler is modulated by varying their distance: decreasing the distance opens the sampling ports, while increasing it restores the sealed state. The capsule achieves high storage efficiency through three key design improvements: optimizing the magnetic moment to increase available internal space, incorporating a ribbed structure to minimize internal friction, allowing a more space-efficient sealing mechanism and utilizing a rigid outer material to maximize internal volume. The final prototype achieves a total storage capacity of 1020 μL per sampling compartment, utilizing 56.36% of the total capsule volume, making it one of the most efficient designs in its category. These results demonstrate the potential of the proposed capsule as a scalable and cost-effective solution for microbiome research and clinical diagnostics.