Layered NiTi Guide Wire for Formable Distal Tip Control
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Solution Overview
Problem
Existing guide wires face challenges in maintaining excellent shape restorability and ease of forming the distal end portion, particularly when navigating branched blood vessels, due to phenomena like 'repellence' that reduce operability and blood vessel selectivity.
Innovation Solution
A guide wire design featuring a core shaft with a nickel-titanium-based alloy body and layered portions containing nickel alloy and titanium oxide, allowing for enhanced formability and shape restorability through superelastic properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the distal end portion of the core shaft is formed into a flat shape to enhance ease of forming, then the core shaft can be easily bent in a direction perpendicular to the flat direction, but the distal end portion becomes difficult to rotate and exhibits repellence during rotation operations
Solution Approach 1:
The core shaft is divided into distinct functional segments: a body portion with superelastic NiTi alloy for shape restorability, and layered portions with nickel alloy inner layer and titanium oxide outer layer for enhanced formability. This segmentation allows each segment to perform its specific function without interfering with the other, resolving the contradiction between ease of forming and rotatability.
Solution Approach 2:
Different regions of the core shaft are given different material properties: the body portion maintains superelasticity for overall shape recovery, while the layered portions have discontinued superelasticity to provide localized ease of forming. This local differentiation allows the distal end to be easily formed without compromising the rotatability needed for navigation.
2Reliability
If the core shaft is made with uniform superelastic properties throughout to maintain excellent shape restorability, then the guide wire can restore its original shape after bending, but the distal end portion becomes difficult to form into desired shapes
Solution Approach 1:
The core shaft features localized material property changes where only specific layered portions have discontinued superelasticity, while the body portion retains full superelastic properties. This allows the distal end to be easily formed into desired shapes while the body portion ensures overall shape restorability after navigation.
Solution Approach 2:
The core shaft uses a composite structure combining NiTi alloy with nickel alloy and titanium oxide layers. This composite material design enables different functional zones along the core shaft, with the layered portions providing enhanced formability through controlled discontinuation of superelasticity while maintaining biocompatibility and structural integrity.
3Ease of manufacture
If the layered portion is extended over the entire outer periphery of the body portion to maximize ease of forming, then the distal end becomes very easy to form, but the overall shape restorability of the guide wire is compromised
Solution Approach 1:
The layered portions are positioned at specific locations rather than covering the entire body portion, creating distinct functional zones. This segmentation ensures that only the necessary regions have enhanced formability while the body portion maintains superelasticity for overall shape restoration.
Solution Approach 2:
The layered portions are strategically placed at specific locations on the core shaft where enhanced formability is needed, while the body portion retains its superelastic properties. This localized approach maintains the balance between ease of forming and shape restorability.
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 design enhances the ease of forming the distal end portion while maintaining excellent overall shape restorability, improving operability and blood vessel selectivity by allowing precise manipulation and navigation.
Implementation Method 1
the body portion contains a nickel-titanium-based alloy having a superelastic property as a main component
Implementation Method 2
the layered portion having an inner layer formed on a part of an outer peripheral face of the body portion and containing a nickel alloy as a main component, and an outer layer formed on the inner layer and containing a titanium oxide as a main component, and the superelastic property in the layered portion disappeared
Data Source
Figure 1~2
Figure 3A~3C
Figure 4A~4B
AI summary
The purpose of the present invention is to provide a guide wire in which ease of forming a distal end portion can be enhanced while maintaining excellent overall shape restorability. A guide wire 1 has a core shaft 11, and is characterized in that the core shaft 11 includes a body portion 11a and a layered portion 11b, the body portion 11a contains a nickel-titanium-based alloy having a superelastic property as a main component, and the layered portion 11b includes an inner layer n formed on a part of an outer peripheral face of the body portion 11a and containing a nickel alloy as a main component, and an outer layer g formed on the inner layer n and containing a titanium oxide as a main component.