https://scholar.dgist.ac.kr/handle/20.500.11750/173 Sat, 03 Oct 2026 21:40:03 GMT 2026-10-03T21:40:03Z https://scholar.dgist.ac.kr/handle/20.500.11750/60897 Title: A Steerable and Expandable Magnetic Aspiration Catheter for Enhanced Aspiration Thrombectomy Author(s): Lee, Hakjoon; Dong, Xiao; Kim, Dong-in; Chowdhury, A. M. Masum Bulbul; Gharamaleki, Nader Latifi; Kim, Jin-young; Youn, Sung Won; Choi, Hongsoo Abstract: Aspiration thrombectomy is widely used when treating acute ischemic stroke. A blood clot is directly suctioned through a catheter connected to a vacuum system. Although an increase in catheter bore size significantly enhances aspiration efficiency, this compromises endovascular navigability during manual manipulation. To minimize this trade-off, this paper presents a novel, magnetic aspiration catheter that enables both active steering and distal-end expansion via externally applied magnetic fields. The catheter incorporates dual-axis magnetization. Axial magnetization facilitates directional steering by aligning the catheter tip with the magnetic field; radial magnetization enables dynamic expansion of the cross-sectional area in response to the field strength, thereby improving clot contact and reducing leakage between the catheter and vessel wall. A magnetic mold-based fabrication method is employed to realize such dual-axis magnetization. The magnetically actuated motions of the catheter are theoretically and experimentally validated. Active steering reduces the navigation time by 67.5% (30.3 vs. 93.1 s) and expansion increases the aspiration force by 430% (27 vs. 143 & micro;N). Catheter efficacy and feasibility in terms of aspiration thrombectomy are demonstrated using 3D vascular phantoms. By enhancing both navigational control and therapeutic performance, this study advances the development of practical robotic systems for rapid and precise stroke treatment. Tue, 30 Jun 2026 15:00:00 GMT https://scholar.dgist.ac.kr/handle/20.500.11750/60897 2026-06-30T15:00:00Z https://scholar.dgist.ac.kr/handle/20.500.11750/60879 Title: Magnetic Control of Intravascular Collaborative Robotic (Cobot) Guidewire: Neurovascular Intervention Studies in Phantom and Swine Models Author(s): Kim, Dong-in; Kim, Beomjoo; Lee, Hakjoon; Hwang, Junsun; Jeon, Sungwoong; Kim, Jin-young; Youn, Sung Won; Choi, Hongsoo Abstract: Strokes such as acute ischemic stroke require vascular access for endovascular thrombectomy. To navigate the small and complex cerebral vessels with multiple branches, clinicians use guidewires or catheters with pre-shaped tips. However, complex procedures still face the problem of increased X-ray exposure for both clinicians and patients. Engineering technologies such as robotic guidewires and catheters are being applied to neurovascular procedures to make them faster and more effective. The technology presented in this study involves Collaborative Robotic (Cobot) guidewires that can be steered by magnetic fields to effectively enter the target vessel and navigate complex blood vessels. The Cobot guidewire can be steered according to the direction of the magnetic field because its tip contains a permanent magnet and a magnetic polymer. The magnetic field for steering the Cobot guidewire can be controlled and generated by electromagnetic control systems (ECS). In this study, the performance of neurovascular procedures using the Cobot guidewire and manual guidewire is compared in both phantom and swine models. Based on various parameters, the Cobot guidewire demonstrates superior performance in neurovascular procedures compared to the manual guidewire. Favorable procedure time and navigation efficiency suggest that a magnetically assisted Cobot guidewire is potentially feasible for neurovascular interventions. Tue, 30 Jun 2026 15:00:00 GMT https://scholar.dgist.ac.kr/handle/20.500.11750/60879 2026-06-30T15:00:00Z https://scholar.dgist.ac.kr/handle/20.500.11750/60611 Title: 96-Well Format-Based Liver–Heart-on-a-Chip Platform for Facile and Parallel Testing of Drug-Induced Cardiotoxicity after Liver Metabolism Author(s): Lee, Sebeen; Jin, Chaewon; Choi, Hongsoo; Kim, Jin-young Abstract: Current preclinical drug evaluation predominantly relies on conventional two-dimensional (2D) cell cultures grown in static environments, which lack dynamic interactions and fail to recapitulate complex microenvironments. These approaches are inefficient and overly simplistic, and often require costly animal models that poorly mimic human physiology. Body-on-a-chip (BoC) technology─comprising robust and flexible three-dimensional (3D) microtissues (MTs)─has emerged to address these limitations. BoC platforms constitute microphysiological systems that mimic human organ physiology and function in vitro, enabling improved toxicity screening and personalized medicine. Here, we present a 96–well format-based microfluidic liver–heart-on-a-chip platform that supports parallel, gravity-driven perfusion to efficiently predict and assess multiorgan drug effects. We demonstrate hepatic metabolism of the cardiotoxic prodrug terfenadine (TFND) into its noncardiotoxic metabolite fexofenadine within liver MTs and the consequent physiological–pathological responses of cardiac MTs. The optimized liver–heart-on-a-chip preserves multitissue functionality, underscores the importance of continuous media circulation, and reveals intertissue interactions relevant to drug-induced cardiotoxicity after liver metabolism. Sat, 28 Feb 2026 15:00:00 GMT https://scholar.dgist.ac.kr/handle/20.500.11750/60611 2026-02-28T15:00:00Z https://scholar.dgist.ac.kr/handle/20.500.11750/60229 Title: A magnetically steerable soft gripper for navigating and grasping in constrained spaces Author(s): Dong Xiao; Lee, Hakjoon; Ahmed, Awais; Choi, Hongsoo Abstract: Magnetic soft grippers hold significant promise for applications requiring gentle and soft interaction with objects. However, steering their movement within constrained spaces remains a major challenge. This study presents a magnetically steerable soft gripper that combines a magnetically steerable soft tube with a magnetic soft gripper. By utilizing distinct magnetization directions for the soft gripper and soft tube, both steering and gripping can be achieved through an external magnetic field. The gripper is capable of lifting objects weighing more than 68 times its own weight under a 40 mT magnetic field (1.7 times per mT). It can also grasp objects of various shapes and sizes. When integrated with a commercial catheter, the steerable gripper successfully performs targeted gripping in a 3D phantom environment. This work introduces a novel magnetically steerable soft gripper system for precise manipulation in confined spaces, with strong potential for applications inside the human body. © The Korean Society of Mechanical Engineers and Springer-Verlag GmbH Germany, part of Springer Nature 2026. Wed, 31 Dec 2025 15:00:00 GMT https://scholar.dgist.ac.kr/handle/20.500.11750/60229 2025-12-31T15:00:00Z