Expansile Polymers with Delayed Expansion for 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
1Speed
If polymers are designed to expand immediately upon implantation, then occlusion effect is achieved quickly, but delivery through microcatheters becomes difficult and unsafe
Solution Approach 1:
The polymer is prepared in a compressed, low-volume state before implantation that allows it to be safely delivered through microcatheters. The expansion action is delayed until after successful delivery, when the polymer then expands to its functional volume to achieve occlusion. This preliminary compressed state resolves the contradiction by separating the delivery phase from the expansion phase.
2Productivity
If polymers are designed with fast expansion rates, then occlusion is achieved quickly, but control and precision during delivery are reduced
Solution Approach 1:
The polymer exhibits dynamic expansion behavior with at least two distinct expansion rates: a first expansion rate during the initial phase and a second expansion rate in a subsequent phase. This dynamic expansion profile allows the polymer to maintain precision during delivery (low expansion rate) while achieving complete occlusion eventually (higher expansion rate), thus resolving the contradiction between speed and precision.
3Object-affected harmful factors
If polymers are made transparent, then biocompatibility is improved, but visualization during implantation becomes difficult
Solution Approach 1:
The polymer incorporates visualization agents (such as radiopaque materials) as discrete particles distributed within the polymer matrix, rather than making the entire polymer opaque. This localized addition of visualization agents allows the polymer to maintain its biocompatible transparent appearance while providing sufficient contrast for imaging during implantation procedures, thus resolving the contradiction between biocompatibility and detectability.
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 delivery through microcatheters without immediate expansion, and visualization during implantation, effectively occluding vascular malformations.
Implementation Method 1
The monomer used in the herein described polymers can be pH sensitive and provide a first expansion to the expansile polymer
Implementation Method 2
The second cleavable crosslinker imparts a secondary 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.