3D Printed Untethered Magnetic Bulb for Liquid Biopsy and Drug Delivery

The untethered manipulation of miniature mag-netic mechanisms holds promise for applications in liquid biopsy and drug delivery within the human body. However, employing microrobots for precise liquid manipulation still remains an open challenge. In this study, a novel magnetic mechanism, “magnetic bulb”, which is a millimeter-scale structure resembling pipette rubber bulb, is fabricated using our lab-developed Digital Light Processing-based (DLP-based) 3D printing system. The magnetic bulb can be actuated by magnetic fields to perform various tasks such as sampling, transportation, and controlled release of target liquids. Served as a modular design, the magnetic bulb is assembled with robust external cage to develop an integrated bulb-cage capsule with enhanced sampling capability and resistance to external compression. The resulting capsule has demonstrated effective fluid sampling within a stomach model and drug delivery to biological tissues. Additionally, a magnetic swimmer is crafted by 3D-printing a helical tail onto the magnetic bulb, exhibiting improved locomotion capability and maneuverability by magnetic fields in aerial-aquatic scenarios.