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Braided Nitinol for Medical Applications
Nitinol is a metal alloy of nickel and titanium. It is a well-known shape memory alloy that also exhibits superelasticity and excellent biocompatibility, making it an ideal material for medical implants. Braided nitinol is commonly used in the construction of stents and implantable cardiovascular, neurovascular, and orthopedic devices, among other uses.
Physical Properties of Braided Nitinol
- High strength: 500/1400 MPa
- Very low stiffness: ≈25 GPa
- Good fatigue resistance
- Excellent corrosion resistance
- High biocompatibility: see below
- Excellent shape memory: see below
- Superelasticity: see below
- Composition: 45% titanium, 55% nickel
While nitinol is natural biocompatible, passivation can further improve this property. Passivation removes corrosive elements from the material and creates an oxide layer on its surface. This oxide layer enhances corrosion resistance, protects the human body from the material, and protects the material from the human body. Electropolishing or other specialized medical coatings can also be added to braided nitinol to improve its biocompatibility without affecting its other beneficial characteristics.
What is A “Shape Memory Alloy”?
A shape memory alloy, such as nitinol, is one that “remembers” its original shape. While easily deformed into new shapes, a shape memory alloy will return to its original shape when heated. This characteristic makes braided nitinol a lightweight and effective alternative to “conventional” mechanical actuators in medical devices.
What Does “Superelasticity” Mean?
Like most shape memory alloys, braided nitinol exhibits superelasticity. Superelasticity, sometimes called “pseudoelasticity”, is a reversible response to applied stresses, enabled by a phase transformation between austenitic and martensitic crystalline structures within the material. The superelasticity of braided nitinol gives it flexibility and resilience similar to that of human bone.
Braided Nitinol for Stents
Braided nitinol is exceptionally useful as a material for medical stents. A collapsed stent can be inserted into a vein or artery and, thanks to its shape memory characteristics, the stent will return to its original expanded shape when heated by body temperature.
Braided Nitinol for Neurovascular Devices
Relying on that same shape memory alloy function, collapsible braided nitinol structures can also be used for neurovascular interventions to improve blood flow. Braided nitinol medical devices are commonly used for intracranial angioplasty, stroke thrombolysis, and embolization.
Custom Nitinol Braids from US BioDesign
US BioDesign specializes in producing nitinol braids for all types of medical applications. Our medical nitinol solutions can be customized to your unique needs. We work with microscopically-thin nitinol fibers (just a few hundred micrometers thick) to create braided nitinol shapes that are flexible enough and strong enough to be guided through challenging anatomies without causing harm, and durable enough to last as long as the procedure requires—often permanently.
We will work with you to develop custom braided nitinol shapes that meet your application and performance requirements. We are ISO 13485:2003 registered.
Contact Us for Medical Nitinol Solutions
We are the proven experts in custom braided nitinol shapes for implantable devices and other medical applications. Contact US BioDesign to learn more about our braided nitinol capabilities, or request a quote to get started on your project.