First-of-its-kind microcatheter for targeted endovascular interventions

A first-of-its-kind submillimeter magnetically actuated soft rotatable-tipped microcatheter (MSRM) developed by a cross-disciplinary research team from the Chinese University of Hong Kong (CUHK) may potentially provide faster, safer, and more precise solution for treating life-threatening blood vessel blockages in the brain.

“The MSRM features a soft, rotatable tip that can be guided wirelessly using external magnetic fields, which enables precise navigation through complex blood vessels. Once it reaches the blockage, the MSRM can directly deliver clot-dissolving drugs, mechanically break down the clots, and safely retrieve clot debris,” explained Professor Li Zhang of the Department of Mechanical and Automation Engineering, CUHK. “This all-in-one design eliminates the need for tool exchanges, reduces procedural risks, and significantly enhances treatment efficiency.” [Sci Adv 2025;11:eadv1682]

Research has shown that every minute lost between ischaemic stroke onset and treatment results in 1.9 million neurons lost, translating into 3.1 weeks of accelerated ageing. Rapid intervention is thus critical. [Stroke 2006;37:263-266]

Mechanical thrombectomy, which physically removes or retrieves blood clots, provides prompt and effective endovascular treatment for large vessel disease. Recent studies have shown that the procedure is becoming increasingly feasible for distal medium vessel occlusions (DMVO). [Sci Rep 2023;13:5730; Neurointervention 2025;20:15-23] However, challenges remain with use of microcatheters in small blood vessels.

These challenges include maintaining high flexibility in the complex vascular system, delivery of efficient and effective therapy, and potential endothelial damage from the physical interaction between rigid actuation units and fragile blood vessels, particularly in terminal arteries that are prone to avulsion or rupture. [Med Phys 2007;34:3135-3142;  IEEEASME Trans Mechatron 2022;27:1761-1772; Research (Wash DC) 2023;6:0048; Nat Rev Neurol 2009;5:181-182]

To address these challenges, the CUHK research team thus developed a submillimeter-scale (0.8 mm for the prototype, with potential for reduction to 0.1 mm), soft-tipped magnetic microcatheter for navigating vascular systems with ≥1 mm diameter, such as cortical branch arteries in the MS and M3 segments or transition bifurcations from the M3 and M4 segments of the middle cerebral artery.

“Unlike conventional tools, the MSRM’s soft silicone-based tip and low rotation speed [2–8 Hz] minimize trauma to delicate brain vessels. In tests using human placenta blood vessels, which closely resemble cerebral arteries, the MSRM showed minimal cell damage compared with the notable vessel wall damage caused by traditional guidewires,” added Professor Thomas Wai-Hong Leung of the Department of Medicine and Therapeutics, CUHK. “This novel device addresses key limitations in current stroke interventions and offers hope for better stroke treatment.”