Stent Surface Topography for Endothelialization
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Solution Overview
Problem
Current stents, both drug-eluting and bare metal, face challenges such as late stent thrombosis and restenosis due to incomplete endothelial coverage and excessive smooth muscle cell proliferation, which leads to neointima formation and vessel narrowing, necessitating improved surface topography for enhanced endothelialization and reduced inflammatory response.
Innovation Solution
A stent with a surface layer featuring a specific line pattern of ridge and groove widths in the sub-micron to micrometer regime, optimized for cell adhesion and proliferation, combined with a biodegradable metallic or polymer material, and a topcoat for drug elution, to accelerate endothelialization and reduce thrombogenicity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a flat surface is used on stents, then manufacturing is simple, but endothelial cell adhesion and spreading are poor leading to incomplete coverage
Solution Approach 1:
The stent surface is modified with local topographic features (ridges and grooves) in specific patterns to enhance cell adhesion and spreading in critical areas, while maintaining overall structural integrity. This localized modification improves endothelial coverage without requiring complete surface reconstruction.
Solution Approach 2:
The invention transitions from a two-dimensional flat surface to a three-dimensional structured surface by incorporating ridges and grooves with specific heights and widths. This dimensional change provides additional cues for cell behavior, improving spreading and adhesion through contact guidance mechanisms.
2Reliability
If drug eluting coating is applied to prevent restenosis, then cell proliferation is inhibited, but thrombogenicity increases at incomplete covered areas
Solution Approach 1:
The topographic surface modification is applied preliminarily before drug elution to establish optimal cell adhesion and spreading conditions. This preliminary structural preparation ensures that when the drug eluting coating is applied, the underlying surface topology continues to promote favorable cell behavior, reducing thrombogenicity at the coating interface.
Solution Approach 2:
The invention combines multiple functional layers: the topographic surface structure, the drug eluting polymer coating, and the metallic stent strut. This composite structure integrates the mechanical support of the metal, the cell-guiding topology, and the therapeutic drug elution, creating a synergistic system that addresses both restenosis prevention and thrombosis reduction.
3Productivity
If surface topography is modified to accelerate endothelialization, then healing process is enhanced, but manufacturing complexity increases
Solution Approach 1:
The surface modification is segmented into discrete ridges and grooves with standardized dimensions rather than a continuous complex pattern. This segmentation allows for modular manufacturing using techniques like laser processing or precision molding, where each feature can be independently controlled and reproduced, simplifying the manufacturing process while maintaining biological effectiveness.
Data Source
Figure 1A~1B
Figure 2A~2C
Figure 2D
AI summary
The present invention refers to an implant with a surface layer having a topographic modification. The topographic modification includes a line pattern with ridge and groove widths of 0.9 to 1.1 µm and a ridge height of more than 0.9 µm.