Knitted Stent Drug Loading via Elastic Metal Tube Lumens
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Solution Overview
Problem
Conventional knitted stents face challenges in drug loading due to the difficulty in forming grooves or holes for receiving drugs, and the drug-containing films tend to peel off, leading to unsustained drug release.
Innovation Solution
A knitted stent system that includes a wire spirally coiled about an axis, with elastic metal tubes having release holes in communication with a first lumen, where a liner core fills the lumen to create a drug receptacle, allowing for effective drug loading and release.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If laser-cut stents are used as drug carriers with grooves for drug deposition, then drug loading is achieved, but geometric compliance and fatigue resistance deteriorate, causing the stent to break when significant deformation is required
Solution Approach 1:
The patent uses a knitted stent structure with inherent porosity and interconnected spaces between wires, eliminating the need for laser-cut grooves. The knitted construction provides both drug loading capacity through the porous network and maintained mechanical strength through the continuous wire structure, resolving the contradiction between drug loading and fatigue resistance
Solution Approach 2:
The patent employs composite construction by coating the knitted wire structure with drug-containing materials or filling the porous spaces with drug-eluting polymers. This composite approach allows the stent to combine the mechanical integrity of the knitted metal structure with the drug delivery functionality, achieving both drug loading and fatigue resistance
2Quantity of substance
If drug-containing films are applied directly onto wires of knitted stents by spraying, then drug loading is achieved, but the films easily peel off and sustained drug release cannot be ensured
Solution Approach 1:
The patent nests the drug-containing material within the knitted structure itself, either by filling the internal spaces of the knitted wires or by incorporating drugs into the wire coating before assembly. This nested configuration prevents film peeling by integrating the drug carrier within the structural framework rather than applying it as a surface layer
Solution Approach 2:
The patent applies drug-containing coatings to the wires before the knitting process or incorporates drugs into the wire structure during manufacturing. This preliminary action ensures proper drug placement and bonding before the stent is assembled and deployed, preventing subsequent peeling and ensuring sustained release
3Quantity of substance
If grooves are engraved and drugs are deposited in grooves of laser-cut stents, then drug loading is achieved, but the stent structure becomes complex and manufacturing cost increases
Solution Approach 1:
The patent utilizes the natural porous structure of knitted stents, where the spaces between interlaced wires serve as drug reservoirs. This eliminates the need for additional grooves or complex structural modifications, maintaining simplicity while achieving effective drug loading through the inherent porosity of the knitted construction
Data Source
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AI summary
A knitted stent and a knitted stent system are disclosed, the knitted stent system comprising the knitted stent, a knitted stent (100) is formed by spirally coiling a knitted wire about an axis in an interlaced manner. The knitted wire includes at least one elastic metal tube (110), each elastic metal tube (110) defining a first lumen and having a wall in which release holes (111) in communication with the first lumen are formed. The first lumen can serve as a drug receptacle. A drug can be filled in the receptacle and released from the release holes (111). In this way, the knitted stent (100) can be used as a base of a drug-loaded stent, thus solving the problem of poor geometric compliance and fatigue resistance arising from the use of conventional drug-loaded stents.