Bioadhesive Stent Coating for Anti-Migration
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Solution Overview
Problem
Stent migration after deployment is a significant issue due to the compressible and flexible properties of stents, which can lead to unintended movement from the originally deployed position, affecting the efficacy of treatments in body lumens such as the vascular system, esophagus, and biliary ducts.
Innovation Solution
A stent configuration featuring a bioadhesive layer coated with a biodegradable polymer layer, where the bioadhesive layer provides adhesion to the tissue at the treatment site, and the biodegradable layer prevents self-adhesion during delivery and handling, ensuring the stent remains in place.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If stent is made compressible and flexible for delivery, then ease of delivery is improved, but stent migration tendency increases
Solution Approach 1:
The stent is pre-coated with a bioadhesive layer and a biodegradable polymer layer before delivery. The biodegradable polymer layer acts as a temporary protective coating during delivery that prevents self-adhesion, and after deployment it degrades to reveal the bioadhesive layer that anchors the stent, preventing migration. This preliminary preparation resolves the contradiction by having the stent ready with both deliverability and migration resistance properties built-in before the procedure.
Solution Approach 2:
The coating system undergoes parameter changes over time: the biodegradable polymer layer degrades and disappears, while the bioadhesive layer becomes increasingly active and adhesive. This temporal parameter change allows the stent to have different properties during different phases of the procedure - non-adhesive during delivery for easy handling, and highly adhesive after deployment for migration resistance.
2Reliability
If stent is coated with bioadhesive for anti-migration, then stent stability is improved, but self-adhesion during delivery occurs
Solution Approach 1:
The biodegradable polymer layer serves as an intermediary between the stent and the external environment during delivery. It masks the bioadhesive properties of the underlying layer, preventing unwanted self-adhesion during handling and delivery. After deployment, this intermediary layer degrades, allowing the bioadhesive to interact with the tissue and provide stability. This intermediary resolves the contradiction by temporarily suppressing adhesion when needed and enabling it when needed.
Solution Approach 2:
The coating system creates different local qualities on the stent surface: the biodegradable polymer layer provides a non-adhesive quality during delivery, while the underlying bioadhesive layer provides adhesive quality after the polymer degrades. This spatial and temporal differentiation of surface properties resolves the contradiction between preventing self-adhesion during delivery and enabling tissue adhesion for stability.
3Ease of operation
If biodegradable polymer layer is applied over bioadhesive, then self-adhesion is prevented during delivery, but coating complexity increases
Solution Approach 1:
The biodegradable polymer layer is designed to be temporarily applied and then discarded through biodegradation. It performs its function of preventing self-adhesion during delivery and handling, then naturally degrades and is eliminated by the body's biological processes. This discarding of the temporary coating resolves the complexity issue because the layer is not permanent - it serves its purpose and then disappears, leaving only the essential bioadhesive layer.
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 bioadhesive layer securely anchors the stent to the tissue, while the biodegradable layer erodes post-deployment, reducing stent migration and enhancing the stability of the stent within the body lumen, thereby improving treatment outcomes.
Implementation Method 1
a first coating composition comprising at least one bioadhesive
Implementation Method 2
a second coating composition disposed over the first coating composition, the second coating composition comprising at least one biodegradable polymer
Data Source
AI summary
A stent, the stent including a first coating composition disposed on at least a portion of the outer surface of the stent, the first coating composition having at least one bioadhesive and a second coating composition disposed over the first coating composition, the second coating composition having at least one biodegradable polymer, and methods of making and using the same.