Using untethered microrobots to remove blood clots

Thrombosis occurs when a blood clot forms in a blood vessel and can be fatal if left untreated. Traditional treatments, such as catheter-based thrombectomy and drug-based thrombolysis, can be highly invasive and imprecise, especially in small blood vessels.

De Boer and Ligtenberg et al. show that an untethered microrobot (UMR) can be a less-invasive treatment for blood clots.

“We envisioned a new approach — using small, untethered microrobots that can navigate through the bloodstream, reach clots in hard-to-access areas, and actively break them down in combination with chemical lysis to mitigate the risk of embolism,” said author Islam Khalil.

The UMR treats blood clots with a two-step approach. First, it physically breaks up the clot by pushing through it, then it releases a drug that dissolves the clot. This ensures the clot is completely removed, reducing the risk of embolism.

The researchers controlled the UMR using magnetic fields and showed in their study that it can navigate small, complex vascular environments.

“The UMR can restore blood flow within minutes, showing its potential for minimally invasive thrombosis treatment,” Khalil said.

This study was done using an ex vivo endovascular thrombosis model within the iliac artery. Many crucial steps must be addressed by the international coalition of scientists to begin in vivo testing.

“First, we need to optimize the biocompatibility of the microrobot to ensure safe interactions with living tissues and blood flow dynamics,” Khalil said. “Additionally, comprehensive safety assessments are required, including evaluating vessel wall interactions, clot fragmentation behavior, and the risk of distal embolization. Real-time imaging and control systems must also be refined to ensure precise navigation within complex vascular networks.”

Source: “Wireless mechanical and hybrid thrombus fragmentation of ex vivo endovascular thrombosis model in the iliac artery,” Marcus C. J. de Boer, Leendert-Jan W. Ligtenberg, Iris Mulder, Constantinos Goulas, Anke Klingner, Roger Lomme, Emily A. M. Klein Rot, Dorothee Wasserberg, Yitong Lu, Remco Liefers, Joep K. van der Mijle Meijer, Gabriëlle J. M. Tuijthof, Doron Ben Ami, Udi Sadeh, Oded Shoseyov, Julien Leclerc, Aaron T. Becker, Pascal Jonkheijm, Michiel Warlé, and Islam S. M. Khalil, Applied Physics Reviews (2025). The article can be accessed at https://doi.org/10.1063/5.0233677 .