https://scholar.dgist.ac.kr/handle/20.500.11750/10164 2026-10-03T21:31:43Z 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. 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. 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. 2026-02-28T15:00:00Z https://scholar.dgist.ac.kr/handle/20.500.11750/60592 Title: Polystyrene Nanoplastics Exacerbate CCl4-Induced Liver Fibrosis by Aggravating Stretch-Induced Mechanical Stress in Hepatic Stellate Cells Author(s): Yim, Jae-Hyuk; Kim, Tae-Un; Kim, Woo Jun; Kim, Hee-Yeon; Lee, Seoung-Woo; Kang, Kyung-Ku; Seo, Min-Soo; Kim, Sung Dae; Cho, Young-Eun; Baek, Su-Min; Choi, Seong-Kyoon; Park, Jin-Kyu Abstract: Although studies on the potential hepatotoxicity of nanoplastic depositions are being conducted, there remains a lack of research on the association between nanoplastic depositions and chronic liver disease. Therefore, this research aimed to explore the influence of polystyrene nanoparticles (PS-NPs) on the progression of liver fibrosis and the mechanisms involved in the hepatic stellate cells (HSCs) activation. Chronic exposure to PS-NPs aggravated CCl4-induced liver fibrosis, as evidenced by enhanced collagen accumulation and elevated alpha-smooth muscle actin (alpha-SMA) expression. Most PS-NPs were accumulated in non-parenchymal liver cells, with Kupffer cells exhibiting the highest uptake. This accumulation was associated with enhanced recruitment of CD68-positive macrophages. However, PS-NPs were not associated with TGF-beta expression in CD68-positive cells. Additionally, CD68-positive cells treated with PS-NPs did not affect alpha-SMA expression in HSCs. Further in vitro experiments revealed that alpha-SMA and pSmad2/3 were directly promoted by PS-NPs in both LX-2 HSCs and primary isolated HSCs, indicating a direct stimulatory effect on HSC activation. PS-NPs enhanced pTGFBR1 expression of HSCs by promoting stretch-induced mechanical stress, suggesting a novel pathway through which nanoplastics may exacerbate fibrogenesis. Our findings provide the first evidence that PS-NPs, as xenobiotic particles, can directly promote HSC activation and exacerbate liver fibrosis, indicating potential health risks associated with chronic nanoplastic exposure. 2025-12-31T15:00:00Z