Expansile Polymers for Delayed Controlled Vascular Occlusion
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Solution Overview
Problem
Current medical treatments for occluding structures and malformations resulting from vascular diseases lack polymers with controlled and delayed expansion rates, which are essential for precise delivery and visualization during implantation.
Innovation Solution
Development of expansile polymers, such as hydrogels, formed into filaments with a secondary expansion mechanism using a cleavable crosslinker, allowing for tailored expansion rates and incorporation of visualization agents like barium sulfate for imaging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polymers are designed to expand immediately upon implantation, then occlusion effect is achieved quickly, but delivery precision and safety are compromised due to inability to control expansion timing
Solution Approach 1:
The polymer is prepared in a compressed, low-volume state before implantation that allows it to be delivered through microcatheters. The expansion action is delayed until after delivery, triggered by environmental factors such as pH change or temperature increase at the implantation site, thus achieving both precise delivery and subsequent occlusion
2Reliability
If polymers are made with high expansion ratio to ensure complete occlusion, then occlusion effectiveness is improved, but structural integrity during delivery deteriorates
Solution Approach 1:
The polymer exhibits dynamic mechanical properties that change with environmental conditions. In the delivered state, it maintains a compressed configuration with higher structural integrity. Upon triggering (pH change, temperature increase), it dynamically transitions to an expanded state with lower strength but complete occlusion, thus adapting its properties to different operational phases
3Reliability
If polymers are made transparent for biocompatibility, then biocompatibility is improved, but visualization during implantation deteriorates
Solution Approach 1:
The polymer incorporates radiopaque materials (such as barium sulfate or iodine compounds) that do not compromise biocompatibility but provide sufficient contrast for fluoroscopic and other medical imaging visualization during delivery and implantation, allowing real-time tracking while maintaining patient safety
4Manufacturing precision
If polymers are designed with complex expansion mechanisms for controlled expansion rates, then expansion control is improved, but device complexity increases
Solution Approach 1:
The polymer utilizes changes in environmental parameters (pH, temperature, ionic strength) to trigger and control expansion. By incorporating functional groups or materials that respond to these parameter changes, the polymer achieves controlled expansion rates without requiring complex mechanical structures or multiple components, thus maintaining simplicity while achieving precision
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 polymers provide controlled and delayed expansion, enabling safe and precise delivery through microcatheters without immediate expansion, and visualization during implantation, effectively occluding vascular malformations.
Implementation Method 1
The second cleavable crosslinker can be an acrylate based crosslinker such as a methacrylate based crosslinker. In some embodiments, the second cleavable crosslinker can be an acrylic anhydride based crosslinker.
Implementation Method 2
The monomer used in the herein described polymers can be pH sensitive and provide a first expansion to the expansile polymer.
Implementation Method 3
The expansile devices can include at least one visualization element, which can be metallic powders, gadolinium, superparamagnetic iron oxide particles, barium sulfate, or a combination thereof.
Data Source
AI summary
Described herein are polymers and associated methods to occlude structures and malformations of the vasculature with polymers with delayed controlled rates of expansion. Methods of forming such devices are also disclosed.