Research Project: Wireless Stent-like Soft Millirobots (STENTBOT) for Minimally Invasive Brain Vasculature Disease Treatments
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Contributors
Funders
ID
EC.00204
Authors
Sitti, Metin
Faculty Member
Publications
Combining tethered and untethered magnetic robots via a magnetically triggerable latch for target payload delivery and retrieval
(American Association for the Advancement of Science, 2026) Sitti, Metin; Brockdorff, Michael; Calme, Benjamin; Wang, Tianlu; Tinsley, Luke J.; Davy, Joshua; Lloyd, Peter; Chandler, James H.; Harris, Russell A.; Valdastri, Pietro; School of Medicine; Yes; SCHOOL OF MEDICINE
The reach and scope of minimally invasive surgical procedures can be transformed via the development of continuum robots. Through soft, flexible structures and accurate navigation, previously inaccessible anatomical regions can be safely reached. Dependent on both actuation mode and clinical application, however, rigidity and miniaturization potential can still present substantial challenges. Magnetic soft continuum robots (mSCRs) offer promising solutions to these key questions. Furthermore, micrometer- to millimeter-scale untethered magnetic robots (mUMRs) offer unparalleled miniaturization potential enabling targeted therapeutic delivery. Leveraging the benefits of magnetic actuation, this study introduces a bespoke, continuously magnetized catheter that synergizes the navigational strengths of mSCRs with the functional effectiveness of mUMRs to precisely deliver drug-doped payloads to otherwise unreachable regions deep within the anatomy. In particular, this system uses a magnetic latching mechanism, ensuring precise drug delivery and efficient retrieval, demonstrated in an ex vivo porcine kidney model for organ transplantation-related immunosuppressant delivery.
Adaptive wireless millirobotic locomotion into distal vasculature
(Nature Portfolio, 2022) Sitti, Metin; Wang, Tianlu; Uğurlu, Halim; Yan, Yingbo; Li, Mingtong; Li, Meng; Wild, Anna-Maria; Yıldız, Erdost; Schneider, Martina; Sheehan, Devin; Hu, Wenqi; Department of Mechanical Engineering; School of Medicine; Yes; College of Engineering; SCHOOL OF MEDICINE
Microcatheters have enabled diverse minimally invasive endovascular operations and notable health benefits compared with open surgeries. However, with tortuous routes far from the arterial puncture site, the distal vascular regions remain challenging for safe catheter access. Therefore, we propose a wireless stent-shaped magnetic soft robot to be deployed, actively navigated, used for medical functions, and retrieved in the example M4 segment of the middle cerebral artery. We investigate shape-adaptively controlled locomotion in phantoms emulating the physiological conditions here, where the lumen diameter shrinks from 1.5mm to 1mm, the radius of curvature of the tortuous lumen gets as small as 3mm, the lumen bifurcation angle goes up to 120 degrees, and the pulsatile flow speed reaches up to 26 cm/s. The robot can also withstand the flow when the magnetic actuation is turned off. These locomotion capabilities are confirmed in porcine arteries ex vivo. Furthermore, variants of the robot could release the tissue plasminogen activator on-demand locally for thrombolysis and function as flow diverters, initiating promising therapies towards acute ischemic stroke, aneurysm, arteriovenous malformation, dural arteriovenous fistulas, and brain tumors. These functions should facilitate the robot's usage in new distal endovascular operations.
Heterogeneous multiple soft millirobots in three-dimensional lumens
(American Association for the Advancement of Science, 2024) Sitti, Metin; Wang, Chunxiang; Wang, Tianlu; Li, Mingtong; Zhang, Rongjing; Ugurlu, Halim; Department of Mechanical Engineering; School of Medicine; Yes; College of Engineering; SCHOOL OF MEDICINE
Miniature soft robots offer opportunities for safe and physically adaptive medical interventions in hard-to-reach regions. Deploying multiple robots could further enhance the efficacy and multifunctionality of these operations. However, multirobot deployment in physiologically relevant three-dimensional (3D) tubular structures is limited by the lack of effective mechanisms for independent control of miniature magnetic soft robots. This work presents a framework leveraging the shape-adaptive robotic design and heterogeneous resistance from robot-lumen interactions to enable magnetic multirobot control. We first compute influence and actuation regions to quantify robot movement. Subsequently, a path planning algorithm generates the trajectory of a permanent magnet for multirobot navigation in 3D lumens. Last, robots are controlled individually in multilayer lumen networks under medical imaging. Demonstrations of multilocation cargo delivery and flow diversion manifest their potential to enhance biomedical functions. This framework offers a solution to multirobot actuation benefiting applications across different miniature robotic devices in complex environments.
