Biodegradable Capsule for Shape Memory Polymer Foam Occlusion
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Solution Overview
Problem
Existing medical devices for occluding regions like the left atrial appendage in patients with atrial fibrillation are inadequate in preventing thrombi formation and have manufacturing and deployment challenges.
Innovation Solution
A biodegradable capsule holds an expandable foam member made of shape memory polymer in a compressed configuration, which expands upon degradation to occlude the region, optionally with an expandable framework for support.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an expandable foam member is used to occlude the LAA, then occlusion effectiveness is improved, but the device cannot be delivered through a catheter due to its size
Solution Approach 1:
The expandable foam member is nested within a delivery catheter in a compressed state, allowing it to be delivered through the catheter and then expanded at the target site. This enables the large occlusion device to be delivered through a small access point.
Solution Approach 2:
The foam member transitions from a compressed static state during delivery to an expanded dynamic state at the implantation site. This dynamic transformation allows the device to achieve its full occlusion effectiveness only when needed at the target location.
2Ease of operation
If the foam member is compressed for delivery, then deliverability is improved, but controlled expansion at the target site becomes difficult
Solution Approach 1:
The foam member's physical state is changed from compressed to expanded by altering parameters such as temperature or pressure at the target site. This allows controlled expansion without complex mechanical mechanisms, as the expansion is triggered by environmental parameter changes.
Solution Approach 2:
Complex mechanical expansion mechanisms are replaced with a simpler system that uses material science principles. The foam member expands in response to environmental stimuli such as temperature changes or solvent exposure, eliminating the need for complex mechanical actuation systems.
3Object-affected harmful factors
If existing medical devices are used to occlude the LAA, then thrombi formation prevention is attempted, but the devices are inadequate in preventing thrombi formation
Solution Approach 1:
The foam member is made of porous material that promotes tissue ingrowth and endothelialization. This porous structure allows blood vessels to grow into the device, creating a biological barrier that prevents thrombi formation more effectively than smooth-surfaced devices.
Solution Approach 2:
The device uses composite materials combining biocompatible polymers with surface modifications that promote endothelial cell attachment and growth. This composite approach creates a surface that actively prevents thrombi formation by encouraging beneficial tissue integration.
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 effectively occludes the region, reduces thrombi formation, and provides controlled expansion and deployment, enhancing treatment efficacy.
Implementation Method 1
a biodegradable capsule disposed over the expandable foam member, the biodegradable capsule holding the expandable foam member in the compressed configuration for a first time period, after which the biodegradable capsule degrades
Implementation Method 2
an expandable foam member made of a shape memory polymer, a biodegradable capsule disposed over the expandable foam member, the biodegradable capsule holding the expandable foam member in the compressed configuration
Data Source
AI summary
An occlusive implant includes an expandable foam member in a compressed configuration and a biodegradable capsule disposed over the expandable foam member. The expandable foam member is made of a shape memory polymer, and the biodegradable capsule holds the expandable foam member in the compressed configuration for a first time period, after which the biodegradable capsule degrades, allowing the expandable form member to expand into an expanded configuration.