Aneurysm filling
An aneurysm is a malformation associated with abnormalities of the vascular wall. In about 30% of cases, a rupture of a brain aneurysm leads to instant death, so aneurysms are often compared to ticking bombs in the head.
A research team from Pohang University of Science and Technology (POSTECH) has developed a new method of minimally invasive treatment of brain aneurysms that can prevent their rupture.
Currently, the spiral embolization method is used for the treatment of aneurysms, in which platinum spirals are inserted into the aneurysm cavity. In addition to the high cost (the price of the spiral alone is 550 US dollars, and it takes quite a lot of these to fill the aneurysm), the serious disadvantages of the method are the risk of intraoperative rupture of the aneurysm due to damage to the walls of the abnormal vessel by spirals, insufficient filling of the aneurysm cavity, as well as detaching and migration of the spiral from the installation site.
Hydrogels, which react to temperature, acidity and other factors, as well as have mechanical strength, have attracted the attention of various research groups as a potential embolic material for filling aneurysms. Among them, cross-linked hydrogels are considered the most suitable for embolization due to their easy spatio-temporal control. But the practical use of hydrogels is limited due to toxicity and biological incompatibility. They can also swell, often leading to ruptures. In addition, with the help of existing surgical methods, it is impossible to produce and control photosynthetic hydrogels using light in an intravascular medium, which has a sinuous geometric structure and high absorption capacity.
In order to overcome the disadvantages of spiral and hydrogel embolization, the POSTECH interdisciplinary research group has developed a new structurally stable biocompatible embolization material that does not decompose in the human body. In addition, a new surgical device for the treatment of brain aneurysms was presented, capable of stably forming and controlling the material in the form of microfibers in the intravascular environment. The results of this study were published as the cover of the April issue of the journal Advanced Materials.
The research team proposed using alginate-based hydrogel obtained from algae with tantalum nanopowder, which can be double-stitched, for aneurysm embolization. This new material has excellent biocompatibility and uses the synergistic effect of rapid covalent crosslinking under the influence of harmless visible light and ion crosslinking using calcium ions present in the blood. In addition, since there are no decomposing enzymes in the human body, it does not degrade and demonstrates amazing structural stability without swelling. This hydrogel can safely and effectively fill an aneurysm and successfully prevent rupture. Since it is possible to add a contrast agent to it, the application site can be continuously monitored for a long time using CT or MRI.
The research team has also developed a microfluidic device with an integrated optical fiber. This device can stably produce and control photosynthetic hydrogels in the form of microfibers in an extreme intravascular environment, which has a sinuous geometric structure and high absorption capacity.
Double cross-linked alginate-tantalum hydrogel microfibers produced and controlled in these microfluidic devices can safely and evenly fill aneurysms. At this stage, the microfibers intertwine with each other, forming a plug that blocks the flow of fluid at the entrance to the aneurysm and maintains the structural shape and constant mechanical strength of the vascular wall even in a pulsating medium. This minimizes the occurrence of pressure inside the aneurysm or its rupture.
The new concept of the embolization method developed in this study was successfully tested using an advanced dynamic vascular simulator (Advanced Dynamic Angio Model, ADAM), previously developed by the research group. ADAM is a system that creates a virtual environment very similar to the body of a real patient, and can be used to simulate various vascular diseases.
It is expected that the developed concept will be effectively applied in other vascular diseases requiring embolization.
Article J.Lim et al. Embolization of Vascular Malformations via In Situ Photocrosslinking of Mechanically Reinforced Alginate Microfibers using an Optical-Fiber-Integrated Microfluidic Device is published in the journal Advanced Materials.
Aminat Adzhieva, portal "Eternal Youth" http://vechnayamolodost.ru based on POSTECH materials: Treating Cerebral Aneurysms with a New Filling Method.