Nitinol Stent Fastening With Undercut Projections
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Solution Overview
Problem
Current biomedical fastening means for stents and therapy carriers lack biocompatibility, strength, and the ability to be easily detached and re-fastened without tools, posing challenges for long-term drug delivery and vascular implantation.
Innovation Solution
A miniaturized fastening system using nitinol substrates with undercut projections that hook onto counterparts, allowing for detachable and re-attachable connections without tools, leveraging the super-elastic properties of nitinol for secure and reversible engagement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional fastening means are used for stents and therapy carriers, then mechanical strength can be achieved, but biocompatibility and ease of detachment are compromised
Solution Approach 1:
The patent changes the material parameter from conventional metals to nitinol, which possesses unique properties including super-elasticity and shape memory effect. This material substitution enables the fastening means to achieve both high mechanical strength through elastic deformation and excellent biocompatibility, resolving the contradiction between strength and biocompatibility
Solution Approach 2:
The fastening means utilizes the dynamic super-elastic properties of nitinol to transition between engaged and disengaged states. The elastic projections can dynamically deform to engage with recesses and subsequently release when force is applied, providing both strong attachment and easy detachment without compromising biocompatibility
2Strength
If strong fastening connections are used, then structural integrity is maintained, but ease of detachment without tools is lost
Solution Approach 1:
The fastening connection is segmented into discrete elastic projections on one component and corresponding recesses on the mating component. This segmentation allows the connection to be formed by simple engagement of multiple small features rather than a single strong bond, enabling tool-free attachment while maintaining overall connection strength through the cumulative effect of multiple engagement points
Solution Approach 2:
The elastic projections are designed to be dynamically deformable within their elastic range during engagement, creating a snap-fit connection that is strong when engaged but easily released by applying sufficient force to overcome the elastic retention. This dynamic behavior provides both strong connection and easy tool-free detachment
3Volume of moving object
If miniaturized fastening means are used, then device profile is minimized, but manufacturing precision requirements increase
Solution Approach 1:
The patent utilizes the material parameter changes of nitinol, specifically its super-elasticity and ability to undergo large elastic deformations. This material property allows the elastic projections to be manufactured with slightly larger tolerances while still achieving reliable engagement, as the material can accommodate dimensional variations through elastic deformation rather than requiring precise rigid fits
Solution Approach 2:
The fastening means employs nitinol, which can be considered a composite material system combining the properties of a metal alloy with shape memory and super-elastic characteristics. This composite material approach enables miniaturization while maintaining manufacturing feasibility, as the material's inherent elasticity compensates for the challenges of manufacturing small features with high precision
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 nitinol-based fastening system provides strong, biocompatible, and easily detachable connections, enabling efficient drug delivery and implantation while minimizing mechanical interference and maintaining structural integrity.
Implementation Method 1
A miniaturized fastening system using nitinol substrates with undercut projections that hook onto counterparts, allowing for detachable and re-attachable connections without tools, leveraging the super-elastic properties of nitinol for secure and reversible engagement.
Data Source
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AI summary
The invention relates to a stent and therapy carrier for implantation in the human body, with a substrate (10) composed of nitinol for biocompatible and/or high-strength micro-connections, wherein a large number of undercut projections (20) protrude from the substrate (10) in order to allow the undercut projections (20) to catch on a corresponding mating piece, such that the stent can be connected releasably to the mating piece. The invention further relates to an implant, provided for implantation in the human body and comprising such a fastening means, and to a method for producing the fastening means.