Thermal and Magnetic Dual-Responsive Catheter-Assisted Shape Memory Microrobots for Multistage Vascular Embolization

Qianbi Peng; Shu Wang; Jianguo Han; Chenyang Huang; Hengyuan Yu; Dong Li; Ming Qiu; Si Cheng; Chong Wu; Mingxue Cai; Shixiong Fu; Binghan Chen; Xinyu Wu; Shiwei Du; Tiantian Xu

doi:10.34133/research.0339

Thermal and Magnetic Dual-Responsive Catheter-Assisted Shape Memory Microrobots for Multistage Vascular Embolization

Research (Wash D C). 2024 Mar 26:7:0339. doi: 10.34133/research.0339. eCollection 2024.

Authors

Qianbi Peng^{1

2}, Shu Wang¹, Jianguo Han³, Chenyang Huang^{1

2}, Hengyuan Yu¹, Dong Li¹, Ming Qiu³, Si Cheng³, Chong Wu³, Mingxue Cai¹, Shixiong Fu^{1

2}, Binghan Chen^{1

2}, Xinyu Wu¹, Shiwei Du³, Tiantian Xu^{1

4}

Affiliations

¹ Guangdong Provincial Key Lab of Robotics and Intelligent Systems, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China.
² University of Chinese Academy of Sciences, Beijing, China.
³ Department of Neurosurgery, South China Hospital, Medical School, Shenzhen University, Shenzhen, China.
⁴ The Key Laboratory of Biomedical Imaging Science and System, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China.

Abstract

Catheters navigating through complex vessels, such as sharp turns or multiple U-turns, remain challenging for vascular embolization. Here, we propose a novel multistage vascular embolization strategy for hard-to-reach vessels that releases untethered swimming shape-memory magnetic microrobots (SMMs) from the prior catheter to the vessel bifurcation. SMMs, made of organo-gel with magnetic particles, ensure biocompatibility, radiopacity, thrombosis, and fast thermal and magnetic responses. An SMM is initially a linear shape with a 0.5-mm diameter at 20 °C inserted in a catheter. It transforms into a predetermined helix within 2 s at 38 °C blood temperature after being pushed out of the catheter into the blood. SMMs enable agile swimming in confined and tortuous vessels and can swim upstream using helical propulsion with rotating magnetic fields. Moreover, we validated this multistage vascular embolization in living rabbits, completing 100-cm travel and renal artery embolization in 2 min. After 4 weeks, the SMMs maintained the embolic position, and the kidney volume decreased by 36%.