Plasma-Treated ePTFE-Sleeved Stents for Vascular Cell Ingrowth
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Solution Overview
Problem
Existing cardiovascular stents made of ePTFE face complications such as migration, infection, and aneurysm progression due to lack of biological fixation, primarily because they do not interact with vascular smooth muscle cells effectively.
Innovation Solution
Modifying the ePTFE surface of stents with specific physicochemical properties, including a surface oxygen content between 1.8-2.8% and a water contact angle of 110-125 degrees, enhances cell adhesion and proliferation, particularly of vascular smooth muscle cells, leading to improved stent fixation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ePTFE material is used for stent fabrication, then biocompatibility and thrombogenicity are improved, but biological fixation and cell attachment are lost
Solution Approach 1:
The patent applies plasma treatment to change the surface parameters of ePTFE, specifically increasing surface energy and creating hydrophilic properties. This modifies the surface chemistry and physics to enable cell attachment while preserving the bulk biocompatibility of ePTFE material.
Solution Approach 2:
The invention modifies only the surface properties of ePTFE through plasma treatment, leaving the bulk material characteristics unchanged. This creates a gradient where the surface has enhanced biological activity for cell attachment while the bulk maintains the desired biocompatibility and thrombogenicity resistance.
2Reliability
If ePTFE stent is implanted, then vascular replacement is achieved, but stent migration and lack of fixation occur
Solution Approach 1:
The patent performs plasma treatment on the ePTFE stent surface before implantation to pre-establish surface properties that promote cell attachment and fixation. This preliminary surface modification ensures that when the stent is implanted, the vessel wall cells can immediately begin to adhere and integrate with the stent.
3Ease of manufacture
If conventional ePTFE surface is used, then manufacturing simplicity is maintained, but cell adhesion and proliferation are insufficient
Solution Approach 1:
The patent replaces complex chemical coating or grafting processes with plasma treatment, which is a physical-chemical process that modifies surface properties without requiring additional material layers or complex chemistry. This maintains manufacturing simplicity while achieving enhanced cell adhesion.
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 modified stent surfaces exhibit a 5.9-fold increase in vascular smooth muscle cell biomass, resulting in stronger stent-vessel interaction, reduced movement, and prevention of aneurysm progression.
Implementation Method 1
a vascular stent comprising of ePTFE surface material characterized by a surface oxygen content between 1.8-2.8%
Implementation Method 2
having a water contact angle between 110 - 125 degrees
Implementation Method 3
displayed the most favorable enhanced cell adhesion and cell proliferation
Implementation Method 4
displayed the most favorable enhanced cell adhesion and cell proliferation, in particular of vascular SMCs
Data Source
Figure 1~2
Figure 3A~4B
Figure 5A~6D
AI summary
The invention relates to the fields of biomaterials, tissue engineering and regenerative medicine. More specifically, it relates to biomaterial substrates having precise surface properties and the use thereof to enhance the attachment and ingrowth of ePTFE sleeved stents with the blood vessel wall. The specific physicochemical properties stimulate smooth muscle cell attachment and spreading that enables the stent to be biologically fixated in a very intimate fashion. This biological fixation prevents migration, infection, and aneurysm progression.