Researchers at Stanford University have developed a new medical device that could transform the way doctors remove blood clots.
Blood clots can block arteries and veins, causing strokes, heart attacks, or lung blockages. Doctors often use mechanical thrombectomy to remove them, typically by suction, stent retrievers, or breaking the clot apart. While lifesaving, these methods fail in up to 30% of cases, especially with large, dense clots, and they also risk creating new blockages by releasing fragments.
Published in arXiv, the Stanford team designed a 3D printed device called “milli-spinner,” which works differently from current methods by compressing and reshaping clots rather than cutting them apart. Led by Ruike Renee Zhao, an Assistant Professor in the Department of Mechanical Engineering, the study’s early tests suggest it could make treatments for stroke, pulmonary embolism, and other clot-related conditions faster, safer, and more effective.
Stanford faculty Jeremy J. Heit and Renee Zhao demonstrate how to insert the milli-spinner using a life-sized model of the human circulatory system. Photo via Aaron Kehoe | Stanford.
High-speed spinner shrinks clots safely
To develop the milli-spinners, the team used high-resolution stereolithography (SLA) and digital light processing (DLP) 3D printing. A larger 2.5 mm version was created on a Formlabs 3+ SLA 3D printer using Formlabs Grey resin.
Smaller radio-opaque versions, measuring 1.5, 1.3, and 1.2 mm, were printed on a custom-built digital light processing printer that used a 385 nm UV-LED projector and resin mixed with barium sulfate and iron oxide. These added materials made the devices visible during fluoroscopic imaging, which is essential for guiding procedures in real time.
Once the milli-spinner reaches a clot, it spins rapidly and presses the clot against its surface. This spinning motion squeezes out red blood cells and compacts the clot’s fibrin structure, shrinking its size by as much as 90%. The smaller, denser clot can then be removed more easily. Researchers compare the process to rolling and pressing a cotton ball until it becomes much smaller.
In laboratory experiments, the milli-spinner reduced the size of clots with remarkable speed. Clots rich in red blood cells shrank within seconds, while fibrin-rich clots, which are much tougher and more resistant to existing devices, could still be significantly reduced within a couple of minutes. The device also worked well in fluids with different viscosities, representing the natural variation in human blood.
The milli-spinner can also be adapted to deliver drugs directly to the blockage site. In one demonstration, researchers loaded dye into the hollow core of the device and showed that the release speed could be controlled by adjusting the spin rate. This feature could one day allow clot-dissolving drugs to be delivered more precisely, reducing side effects.
The researchers then tested the device in realistic blood vessel models under fluoroscopic imaging, the same imaging doctors use during real procedures. In a model of pulmonary embolism, the milli-spinner cleared blockages in about 45 seconds, well under a minute.
Similarly for the cerebral artery stroke model, it restored blood flow in just 8 seconds and removed the clot completely in a single attempt. This outcome is particularly notable because current devices often require multiple passes to achieve the same effect.
Manufacturing on Demand
Tests in swine provided further confirmation. When clots were introduced into the renal and facial arteries, which are similar in size and structure to human brain arteries, the milli-spinner removed them in a single procedure after about 2 minutes of clot-debulking.
Imaging showed that blood flow was restored, and tissue analysis confirmed that the endothelium layer of the vessel walls remained intact. When compared with a state-of-the-art aspiration device that failed to remove the same clot in a single run, the milli-spinner showed a much higher success rate.
The researchers reported that the device achieved complete revascularization, or full restoration of blood flow, in more than 80% of cases involving tough clots. They noted that the success rate would likely be even higher for softer clots.
Zhao noted that although the team’s initial work centers on blood clot removal, the milli-spinner could have broader applications. They are already exploring how its targeted suction might be adapted to capture and clear kidney stone fragments.
Close-up of the milli-spinner, which consists of a long, hollow tube that can rotate rapidly, with a series of fins and slits near the clot that help create a localized suction. Photo via Andrew Brodhead | Stanford.
Stanford university’s medical contributions
Away from milli-spinners, Stanford researchers recently developed a computational platform that overcomes a key barrier in organ bioprinting: creating realistic vascular networks to sustain lab-grown tissue.
Published in Science, the algorithm generates vascular trees about 200 times faster than previous methods, integrates fluid dynamics to ensure blood flow and structural feasibility, and outputs 3D printable models. Proof-of-concept prints included a network with 500 branches and tissue rings with embedded vessels that kept human kidney cells alive. While not yet fully functional vessels, this advance brings scalable, patient-specific bioprinted organs significantly closer to reality.
Elsewhere in 2021, Stanford and University of North Carolina at Chapel Hill (UNC) researchers developed a 3D printed microneedle vaccine patch that generated far stronger immune responses than conventional injections. Using Carbon’s CLIP technology, they directly printed sharp, customizable microneedles onto polymer patches, overcoming molding limitations.
In tests, the patches triggered immune responses up to 50 times stronger than subcutaneous and 10 times stronger than intramuscular shots. By targeting skin immune cells, they enabled potential dose sparing while offering painless self-administration, easier storage, and scalable distribution as an alternative to traditional vaccination.
.
You might also like:
Innovative 3D printed talus surgery helps Hyderabad man walk again: Surgeons at Yashoda Hospitals have performed a joint replacement procedure by implanting a custom-made 3D printed titanium talus bone in a 38-year-old patient.
* This article is reprinted from 3D Printing Industry. If you are involved in infringement, please contact us to delete it.
Author: Ada Shaikhnag
Leave A Comment