Histological staining of an untreated vessel with an open lumen lined by endothelial cells through which blood can freely flow (top), and a vessel that was successfully filled and embolized with the Shear-Thinning Biomaterial (STB). Over time, the STB was degraded and replaced by natural tissue in with only remnants of the STB (indicated by asterisks) left at the time of analysis. Credit: Wyss Institute at Harvard University
Researchers from Harvard’s Wyss Institute, Brigham and Women’s Hospital, Mayo Clinic, and MIT have developed a new embolization material that may overcome the limitations of coils and existing liquid embolic agents. The hydrogel material changes its state between liquid and solid in response to physical pressure applied to it. It can be delivered via a catheter directly to a target vessel to completely block any blood from passing through. Unlike with coils, it does not require blood’s own coagulation properties to make it work, making it effective in patients on systemic blood thinners, and unlike existing liquid embolic agents the new material is much easier to control and to place so as not to affect other tissues or nearby stents. Eventually the material biodegrades and is replaced by the body’s own cells.
The material consists of gelatin molecules with tiny discs of silicate nanoplatelets mixed. The nanoplatelets solidify when under little pressure and liquefy when under a lot of it. This property allows it to be squeezed from a syringe as a liquid and to then solidify once it enters a vessel. This was tested by pushing the hydrogel material through existing catheters and analyzed how it can be used to embolize tortuous vessels.
The researchers also applied the material in mice and pigs, demonstrating that the new material was effective at completely occluding large vessels and then biodegrading to be replaced by natural tissue.
The researchers point out that the hydrogel can also be impegnated with contrast agents to be able to see its exact location under live fluoroscopy, which should aid surgeons immensely during embolization procedures.
Here’s a link to a video showing the action of the new biomaterial…
Study in Science Translational Medicine: An injectable shear-thinning biomaterial for endovascular embolization…
