Stent Surface Topography for Endothelial Cell Migration

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Solution Overview

Problem

Intravascular stents face challenges with slow endothelial cell migration onto their surface, leading to potential reocclusion due to injury of the arterial lining and thrombosis, as existing smooth surfaces do not effectively promote cell coverage in all directions, especially when topographical features are oriented perpendicular to blood flow.

Innovation Solution

A noncontiguous pattern of topographical features is created on the surface of medical devices, such as stents, using chemical etching or photolithography, allowing endothelial cells to migrate in multiple directions regardless of device positioning, enhancing cell coverage and preventing thrombosis.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If a smooth surface is used on the stent, then the stent surface is easy to manufacture and maintain, but endothelial cell migration is slow and incomplete

Engineering Contradiction:

Improveendothelial cell migration speedVSAvoidsurface structure complexity

Core Design Contradiction:

SpeedVSDevice complexity

Solution Approach 1:

The surface is segmented into multiple directional grooves arranged in different orientations (e.g., 0°, 45°, 90°, 135° patterns). This segmentation allows endothelial cells to migrate along grooves in any direction, ensuring complete surface coverage regardless of the stent's final positioning orientation in the vessel.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the stent surface have locally optimized groove patterns. The grooves are configured to align with blood flow direction in specific zones, creating locally adaptive surfaces that promote cell migration in the most effective direction for each region while maintaining overall device functionality.

Inventive Principle:

Principle #3Local quality

2Reliability

If topographical features are oriented in a single direction, then the manufacturing process is simpler, but cell coverage is incomplete when the device is positioned perpendicular to the features

Engineering Contradiction:

Improvecell coverage reliabilityVSAvoidmanufacturing process simplicity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

Multiple asymmetric groove patterns are superimposed on the stent surface at different angular orientations. This creates a composite pattern that is asymmetric in multiple directions simultaneously, ensuring that regardless of how the stent is positioned in the vessel, there will always be grooves oriented favorably to guide endothelial cell migration across the entire surface.

Inventive Principle:

Principle #4Asymmetry

3Object-affected harmful factors

If the stent surface is made thrombogenic to prevent cell loss, then platelet deposition increases and thrombosis risk rises

Engineering Contradiction:

Improvethrombosis riskVSAvoidendothelial cell migration rate

Core Design Contradiction:

Object-affected harmful factorsVSProductivity

Solution Approach 1:

The surface topology parameters (groove depth, width, spacing, and orientation) are optimized to create a dual-function surface: the grooves provide mechanical guidance for endothelial cell migration while simultaneously presenting a controlled thrombogenicity that prevents platelet activation. The specific dimensional parameters of the grooves are tuned to favor cell migration over thrombus formation.

Inventive Principle:

Principle #35Parameter changes

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 noncontiguous pattern significantly accelerates endothelial cell migration and coverage, reducing the risk of reocclusion and thrombosis by ensuring cells can migrate in the direction of blood flow, improving the biocompatibility and efficacy of stent placement.

Implementation Method 1

A noncontiguous pattern of topographical features is created on the surface of medical devices, such as stents, using chemical etching or photolithography

Methodology Applied

Scientific EffectChemical etching:

Implementation Method 2

A noncontiguous pattern of topographical features is created on the surface of medical devices, such as stents, using chemical etching or photolithography

Methodology Applied

Scientific EffectPhotolithography:

Data Source

PatentUS11471259B2Topographical features and patterns on a surface of a medical device and methods of making the same

Publication Date: 2022.10.18 VACTRONIX SCIENTIFIC LLC

AI summary

The invention relates to medical devices that has a surface configured to promote the migration of cells onto the surface of the medical device. In particular, the surface of the medical device has a noncontiguous pattern of topographical features formed therein or thereon.