Biodegradable Shape Memory Embolic Device for Predictable Vascular Occlusion
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Solution Overview
Problem
Current biodegradable embolic devices for vascular embolization lack precision and predictability in occluding blood vessels, often leading to unpredictable degradation rates and complications such as residual thrombi or fibrotic changes, which hinder repeat procedures like those in liver cancer treatments.
Innovation Solution
A biodegradable shape memory polymer or copolymer strand with a water-responsive element that transitions from a deformed shape to an original shape upon exposure to fluid, allowing for controlled and predictable occlusion and degradation, facilitating repeat embolization procedures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If Gelfoam is used as a biodegradable embolic agent, then it can be resorbed in days to weeks, but permanent occlusion may occur by residual organized thrombi or fibrotic change and the occlusion level is unpredictable
Solution Approach 1:
The invention changes the physical state parameter of the embolic device from solid to liquid at room temperature, and to gel/semi-solid at body temperature. This parameter change ensures predictable occlusion by eliminating the variability associated with irregular solid fragments while maintaining biodegradability and controlled resorption time.
Solution Approach 2:
The embolic device utilizes phase transition between liquid and gel states based on temperature. The device is injected as a liquid at room temperature for easy delivery, then transitions to a gel state at body temperature to provide reliable and predictable occlusion. This phase transition resolves the contradiction by ensuring consistent behavior while maintaining biodegradability.
2Duration of action of moving object
If Gelfoam is used for embolization, then it is biodegradable, but it tends to aggregate in vessels more proximally than intended and small fragments may migrate into capillary beds
Solution Approach 1:
The invention changes the physical state from solid particles to a liquid-gel system. This parameter change prevents aggregation and migration issues because the liquid formulation flows smoothly to the target site without irregular fragment behavior, while the gel state at body temperature ensures precise localization. The biodegradability is maintained through selection of biodegradable polymer components.
Solution Approach 2:
The invention uses a formulation that replicates the desirable flow and occlusion properties of solid embolic agents while eliminating their drawbacks. The liquid-gel system copies the occlusion function of Gelfoam but without the aggregation and migration problems, achieving better target precision while maintaining biodegradability.
3Reliability
If fibrin glue is used as a biodegradable liquid embolic agent, then it has good biocompatibility, but it degrades fast and requires double-lumen catheterization
Solution Approach 1:
The invention uses composite materials consisting of biodegradable polymer components (such as PLGA, PCL, or gelatin) combined with crosslinking agents. This composite formulation provides both good biocompatibility and controlled degradation rate. The crosslinking structure slows degradation compared to fibrin glue while maintaining biocompatibility, and the single-lumen catheter compatibility is achieved through the stable liquid-gel formulation.
Solution Approach 2:
The invention changes the degradation rate parameter by introducing crosslinking mechanisms and selecting polymers with appropriate degradation kinetics. This allows the device to maintain occlusion effectiveness for the required duration while still being biodegradable. The crosslinked structure prevents fast degradation seen in fibrin glue, and the liquid-gel state enables single-lumen catheter delivery.
4Reliability
If solid embolic devices in the form of coil are used for GDA embolization, then they provide permanent occlusion, but permanent occlusion is unnecessary since reflux prophylaxis is only relevant during delivery of radioactive particles
Solution Approach 1:
The invention changes the temporal parameter of occlusion by using biodegradable materials that transition from providing effective occlusion to gradually degrading. This allows the device to provide reliable occlusion during the critical period of radioactive particle delivery, then naturally degrade to allow restored blood flow, achieving adaptability between temporary and permanent occlusion needs.
Solution Approach 2:
The embolic device is designed to be discarded after serving its protective function. The biodegradable material naturally degrades and is absorbed by the body, allowing the vessel to recover and restore blood flow. This eliminates the need for permanent occlusion devices while ensuring effective protection during the critical delivery period.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enables precise and temporary occlusion of blood vessels with predictable degradation, allowing for repeated embolization procedures and improved safety in treatments like TACE and SIRT for liver cancer, reducing the risk of permanent occlusion and complications.
Implementation Method 1
the water-responsive element is configured to swell upon exposure to the fluid medium
Implementation Method 2
The biodegradable shape memory polymer or copolymer strand is provided in the deformed shape and configured to resume the original shape in response to exposure to a fluid medium
Data Source
Figure 1A~1B
Figure 1C
Figure 2
AI summary
According to embodiments of the present invention, an embolic device for embolizing a target vascular site is provided. The embolic device includes a biodegradable shape memory element having an original shape and a deformed shape, wherein the biodegradable shape memory element in the deformed shape is in at least one dimension of a smaller size than the biodegradable shape memory element in the original shape, and wherein the biodegradable shape memory element is provided in the deformed shape and configured to resume the original shape in response to an external stimulus being applied to the biodegradable shape memory element in its deformed shape, to embolize the target vascular site and prevent fluid flow through the target vascular site. According to further embodiments of the present invention, an apparatus for embolizing a target vascular site and a method thereof are also provided.