Occlusion of the T-tube (tympanostomy tube) is a common postoperative sequela related to bacterial biofilms. Confronting biofilm-related infections of T-tubes, maneuverable and effective treatments are still challenging presently. Here, we propose an endoscopy-assisted treatment procedure based on the wobbling Fe
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helical micromachine (HMM) with peroxidase-mimicking activity. Different from the ideal corkscrew motion, the Fe
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HMM applies a wobbling motion in the tube, inducing stronger mechanical force and fluid convections, which not only damages the biofilm occlusion into debris quickly but also enhances the catalytic generation and diffusion of reactive oxygen species (ROS) for killing bacteria cells. Moreover, the treatment procedure, which integrated the delivery, actuation, and retrieval of Fe
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HMM, was validated in the T-tube implanted in a human cadaver ex vivo. It enables the visual operation with ease and is gentle to the tympanic membrane and ossicles, which is promising in the clinical application.
The recent rise of swarming microrobotics offers great promise in the revolution of minimally invasive embolization procedure for treating aneurysm. However, targeted embolization treatment of aneurysm using microrobots has significant challenges in the delivery capability and filling controllability. Here, we develop an interventional catheterization-integrated swarming microrobotic platform for aneurysm on-demand embolization in physiological blood flow. A pH-responsive self-healing hydrogel doped with magnetic and imaging agents is developed as the embolic microgels, which enables long-term self-adhesion under biological condition in a controllable manner. The embolization strategy is initiated by catheter-assisted deployment of swarming microgels, followed by the application of external magnetic field for targeted aggregation of microrobots into aneurysm sac under the real-time guidance of ultrasound and fluoroscopy imaging. Mild acidic stimulus is applied to trigger the welding of microgels with satisfactory bio-/hemocompatibility and physical stability and realize complete embolization. Our work presents a promising connection between the design and control of microrobotic swarms toward practical applications in dynamic environments.
The magnetic field has unique advantages in manipulating miniature robots working inside the human body, such as high transparency to biological tissue and good controllability for field generation. Generally, the actuated magnetic robot can be classified into two categories: tethered devices like intravascular microcatheters and untethered devices like helical swimmers. Among these, the tethered devices have a long history and good clinical application prospects, considering their high‐dose delivery and easy removal after the procedure. As an evolution of traditional continuum medical devices, the integration with magnetic actuation provides them with better scalability and improved dexterity. Although rapidly developed in the last two decades, the field of tethered magnetic robots requires further advancements in terms of design, fabrication, modeling, and control, especially for clinical applications. Herein, the recent progress of magnetically actuated continuum medical robots is focused on, intending to offer readers a comprehensive survey of the state‐of‐the‐art technologies and an information collection for future system design.
Long‐distance endovascular navigation of miniature robots under the guidance of medical imaging modalities is essential for microrobotic targeted delivery in the human body. Herein, a scheme on this topic based on mobile ultrasound (US) tracking and magnetic control is proposed. Considering the narrow 2D imaging of a US probe and the fast decay of the magnetic field, the US probe is integrated with three electromagnetic coils for simultaneous long‐distance tracking and control of untethered miniature robots. To enable robust tracking with pulsatile flow, a tracking strategy consisting of tracking in and perpendicular to the image plane is designed. In the image plane, an iterative statistics‐based strategy is proposed to extract the position and orientation of the robot from the US imaging. For the direction perpendicular to the US image plane, the probe motion is automatically adjusted according to the tracking quality. Based on the real‐time tracking result, demanded rotating fields are generated by the mobile coils for helical propulsion. The proposed scheme is implemented on a full‐scale silicone phantom of human iliac and aorta arteries with blood‐mimicking fluid and pulsatile flow. Experimental results validate the robustness and the effectiveness of the proposed scheme.
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