Absorbable Iron Stent Coating for Controlled Corrosion and Low Thrombosis
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Solution Overview
Problem
Current degradable iron-based alloy stents face issues with slow degradation, leading to insufficient mechanical support and potential thrombosis due to excessive zinc ion release, which complicates vascular healing and increases thrombosis risk.
Innovation Solution
An absorbable implantable device with a zinc-containing protective layer and a corrosion promoting layer is designed, where the thickness ratio of the zinc-containing protective layer to the corrosion promoting layer varies on the outer and inner walls to control corrosion initiation and acceleration, reducing zinc ion release and promoting vascular repair.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a zinc-containing protective layer is applied to the iron-based substrate, then corrosion resistance is improved, but zinc ion release increases causing hemolysis and thrombosis risk
Solution Approach 1:
The patent applies different thickness ratios of the zinc-containing protective layer to different locations: a first thickness ratio for the outer wall and a second thickness ratio for the inner wall. This local differentiation allows the outer wall to have sufficient corrosion resistance while the inner wall minimizes zinc ion release into the blood, preventing hemolysis and thrombosis.
Solution Approach 2:
The patent changes the thickness parameter of the zinc-containing protective layer based on location. By setting different thickness ratios (first thickness ratio for outer wall, second thickness ratio for inner wall), the patent optimizes both corrosion resistance and biocompatibility, resolving the contradiction between protection and harmful ion release.
2Reliability
If the zinc-containing protective layer is made thicker, then corrosion protection is improved, but the risk of thrombosis increases due to excessive zinc ion release
Solution Approach 1:
The patent differentiates the zinc layer thickness between outer and inner walls. The outer wall receives a thicker layer (first thickness ratio) for corrosion protection, while the inner wall receives a thinner layer (second thickness ratio) to minimize zinc ion release into blood, thereby reducing thrombosis risk.
Solution Approach 2:
The corrosion promoting layer acts as an intermediary that controls the degradation behavior of the zinc-containing protective layer. It regulates zinc ion release kinetics, allowing controlled protection while preventing excessive rapid release that would cause thrombosis.
3Strength
If the degradable iron-based alloy stent degrades too slowly, then mechanical support is maintained, but vascular healing is delayed and thrombosis risk increases
Solution Approach 1:
The patent applies a corrosion promoting layer in advance on the zinc-containing protective layer. This preliminary action prepares the system for controlled acceleration of degradation after the protective layer has served its initial purpose, allowing the stent to maintain mechanical support when needed and then degrade appropriately to promote healing.
Solution Approach 2:
The patent creates a dynamic degradation system where the corrosion promoting layer accelerates the degradation of the zinc-containing protective layer over time. This dynamic behavior allows the stent to provide mechanical support during the critical early period and then degrade at an appropriate rate to promote vascular healing and eliminate thrombosis risk.
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 device provides early structural support while delaying corrosion initiation, accelerating vascular healing, and reducing thrombosis risk by controlling zinc ion release, ensuring safe and effective vascular function restoration.
Implementation Method 1
a zinc-containing protective layer... disposed on the iron-based substrate... the zinc-containing protective layer covers the outer wall and the inner wall of the iron-based substrate
Implementation Method 2
a corrosion promoting layer... disposed on the iron-based substrate... the corrosion promoting layer covers the zinc-containing protective layer
Data Source
AI summary
An absorbable implantable device, including an iron-based substrate, and a zinc-containing protective layer and a corrosion promoting layer provided on the iron-based substrate. The iron-based substrate has an outer wall and an inner wall. The zinc-containing protective layer covers the outer wall and the inner wall of the iron-based substrate. The corrosion promoting layer covers the zinc-containing protective layer. The thickness ratio of the zinc-containing protective layer located on the outer wall to the corrosion promoting layer located on the outer wall is less than the thickness ratio of the zinc-containing protective layer located on the inner wall to the corrosion promoting layer located on the inner wall. The absorbable implantable device has a low risk of thrombosis and can meet the requirements of early support and later rapid corrosion.