
Nitinol — a nickel-titanium alloy — is used for medical devices such as stents, heart valves, catheters and orthopedics. [Photo via Adobe Stock]
Nitinol is a nearly equiatomic metal alloy of nickel and titanium with unique properties, including superelasticity (also called pseudoelasticity) and shape memory.
Superelasticity/pseudoelasticity means medical-grade nitinol shows great elasticity under stress and can snap back to its original shape when pressure is released.
Nitinol’s superelastic properties allow medical devices using it to compress to a lower profile when being placed in a patient using a catheter. Implants made of nitinol such as heart valves expand to their intended size and shape at the site of implantation and remain inside the patient, while nitinol therapy devices such as ablation catheters expand inside the body, treat targeted tissue, and then compress again for retrieval.
Free webinar: Nitinol knowledge with former Edwards Lifesciences Engineering SVP Ming Wu
Shape memory means medical-grade nitinol can remember its original shape and return to it when heated. For example, some catheter-delivered implants are designed to expand to their pre-formed shape at body temperature for permanent placement.
A promising application of nitinol’s shape memory properties is under development by heart failure startup Adona Medical, which is working on a heart shunt device that can be adjusted for variable flow rates.
“With an increasing trend to treat patients using minimally invasive procedures, nitinol has become a popular choice of material due to its ability to return to its original shape after being mechanically deformed or after heat is applied,” the FDA said in a nitinol guidance document. “These properties are due to reversible transformations between the austenite and martensite phases, which may be temperature-induced (shape-memory) or stress-induced (pseudoelasticity). As a result, nitinol can withstand greater amounts of reversible deformations without plastic deformation than conventional metallic alloys, such as stainless steel, titanium, or cobalt-chrome alloys.”
Nitinol medical devices include:
- Implantable cardiac devices, such as the frames of replacement heart valves that can be placed using catheter delivery (Medtronic’s Harmony valve is one example), Abbott’s implantable clips to repair leaky heart valves, or CroíValve’s tricuspid valve repair implant. V-Wave (set to be acquired by Johnson & Johnson MedTech) has developed an investigational interatrial shunt with nitinol for heart failure. Surgical robotics developer Capstan Medical uses nitinol to expand and anchor the catheter-delivered heart valves its developing.
This illustration shows the nitinol frictional elements on Abbott TriClip’ grippers securing a tricuspid heart valve’s leaflets. [Image courtesy of Abbott]
- Stents and stent retrievers, such as the Johnson & Johnson MedTech Embotrap device for removing blood clots (thrombectomy) in ischemic stroke patients, Retriever Medical’s nitinol basket catheters, and self-expanding pediatric stents under development
- Cardiac pulsed field ablation (PFA) catheters such as those developed by Medtronic, Affera (purchased by Medtronic, these catheters use nitinol both to expand inside a patient’s heart and as electrodes for generating the energy fields), Boston Scientific, J&J MedTech’s Biosense Webster and Abbott.
Medtronic’s Affera Sphere-360 pulsed field ablation catheter is adjustable, allowing the nitinol electrode to take different shapes inside a patient. [Illustration courtesy of Medtronic]
- Renal denervation (RDN) systems that treat hypertension, such as Medtronic’s Symplicity Spyral radiofrequency catheter and the needles that deliver alcohol in Ablative Solutions’ Peregrine catheter
- Synchron‘s catheter-placed Stentrode brain-control-interface implant
- Peripheral intervention devices such as LimFlow’s first-of-its-kind system for avoiding amputations due to chronic limb-threatening ischemia
- Dentistry, especially in orthodontics for wires and brackets that connect the teeth. “Sure Smile” dental braces are an example of its application in orthodontics.
- Endodontics, mainly during root canals for cleaning and shaping root canals
- In colorectal surgery, nitinol is used in various devices for reconnecting the intestine after a pathology is removed.
- Orthopedic implants
- Surgical robotics, such as this prototype for pediatric brain tumor procedures
- Wires for marking and locating breast tumors
- Tubing for a range of medical applications
- Dissolvable devices (in research at MIT)
- Mechanical actuation to fight muscle atrophy (in research at Harvard)
How did nitinol get its name?
The name “nitinol” comes from the metals nickel and tItanium plus “NOL” for Naval Ordnance Laboratory. That’s the U.S military explosives testing facility (now known as the Naval Surface Warfare Center) in White Oak, Maryland, where nitinol was developed. Fun fact: The former NOL facility in White Oak is now the FDA’s headquarters.
More nitinol know-how from Medical Design & Outsourcing:
- Medical nitinol manufacturing: How this nickel-titanium alloy is made for medical devices
Medical nitinol processing turns a solid tube into stents like these — one compressed and the other expanded. [Photo by Zarathustra via Adobe Stock]
- Medical nitinol processing: How NiTi is turned into wire, tubes and sheets for devices
- Nitinol machining and finishing for medical devices
- How Medtronic uses nitinol to improve the structure and effectiveness of heart devices
- What’s next for nitinol tubing?
- Understanding nitinol implant design and manufacturing
- Avoid these four common blunders when using nitinol for medical devices
Notable nitinol supply chain updates
- January 2025: MedRes expands its Nitinol Technology Center in California
Titanium sponge (pictured) is a key ingredient for medical nitinol manufacturing. [Photo by Alexey Rezvykh via Adobe Stock]
- December 2024: Fort Wayne Metals expands nitinol melt capacity as device demand surges
- November 2024: Resonetics VP Eric Veit on medical nitinol lead times, prices and ‘major changes’ in the works
- November 2024: MDC acquires nitinol-based medical components maker Lighteum
- November 2024: Nitinol prices climb for medical devices after melting deals
- September 2024: Resonetics opens second manufacturing facility in Costa Rica
- July 2024: Johnson Matthey completes $700M Medical Device Components sale
- March 2024: Montagu to buy Johnson Matthey Medical Device Components for $700M
- January 2024: Confluent Medical Technologies invests to expand ATI nitinol melting infrastructure
- October 2023: Resonetics closes $900M nitinol deal and rebrands Memry and Smart Materials
- December 2022: Johnson Matthey opens medical nitinol facility in Mexico
- August 2022: Confluent expands Costa Rica manufacturing footprint for nitinol, complex catheter production
- June 2022: Resonetics acquires Agile MV
- February 2022: Confluent closes majority investment from TPG Capital
- December 2021: Carlyle makes a significant investment in Resonetics
- November 2021: Resonetics buys Hudson Medical Innovations
- November 2021: Confluent opens new tubing center in Tennessee
- April 2021: Resonetics to expand manufacturing in Costa Rica
- January 2021: Confluent inks nitinol supply deal with melter Allegheny Technologies (ATI)
- November 2020: Resonetics acquires medical business of Hutchinson Technology
- August 2020: Confluent opens catheter development center in Austin, Texas
- September 2019: Resonetics acquires Tru Tech Systems
- February 2019: Confluent acquires Tube Hollows International for nitinol gun-drilling
- February 2019: Resonetics acquires Caribou Technologies
Find more information about nitinol and other materials used for medical devices in our Medical Device Handbook.
This post was originally published in 2016 and most recently updated in January 2025.
Hi, I was curious to understand what the author’s take is on the current value of the Nitinol market within the medical device industry. Additionally, how would they estimate the growth rate of nitinol based devices?
Many thanks and best regards,
Mithila