Is nitinol a super alloy?
Nitinol is a near-equiatomic nickel and titanium metal alloy with unique properties, including superelasticity (also known as pseudoelasticity) and shape memory.
Superelasticity/quasi-elasticity means that Nitinol exhibits great elasticity under pressure and can return to its original shape when the pressure is released.
Nitinol's superelastic properties allow medical devices using it to compress to a lower profile when placed through a catheter in a patient's body. Implants made of NiTi, such as heart valves, expand to the desired size and shape at the implantation site and remain in the patient's body, while NiTi treatment devices, such as ablation catheters, expand within the body, treating the target tissue, Then compress again to retrieve.
Shape memory means that NiTi can remember its original shape and return to its original shape when heated. For example, some catheter-delivered implants are designed to expand at body temperature to their preformed shape for permanent placement.
One promising application for the shape memory properties of nitinol is being developed by heart failure startup Adona Medical, which is developing a cardiac shunt device that can regulate variable flow rates.
"With the increasing trend toward using minimally invasive procedures to treat patients, Nitinol has become a popular material of choice due to its ability to return to its original shape after mechanical deformation or heating," the FDA said in a Nitinol guidance document. shape." . "These properties are due to the reversible transformation between the austenite and martensite phases, which may be temperature-induced (shape memory) or stress-induced (pseudo-elasticity). Therefore, with stainless steel, titanium or cobalt-chromium alloys Compared with traditional metal alloys, Nitinol can withstand a greater degree of reversible deformation without plastic deformation."
Medical applications of NiTi alloys include:
Implantable heart devices, such as replacement heart valves that can be delivered and placed through a catheter (Medtronic's Harmony valve is one example)
Dentistry, especially orthodontics with the wires and brackets used to connect teeth. "Sure Smile" braces are an example of its use in orthodontics.
Endodontic treatment, which involves cleaning and shaping the root canals during root canal treatment
In colorectal surgery, the material is used in various devices to reconnect the intestine after removal of lesions.
Stents and stent retrievers, such as the Johnson & Johnson Embotrap device, are used to remove blood clots in ischemic stroke patients (thrombectomy)
orthopedic implants
Threads used to mark and locate breast tumors
Pipes for a variety of medical applications
ablation catheter tip
Mechanical actuation combats muscle atrophy (Harvard study)
Dissolvable device (under research at MIT)
Synchron's catheter-insertable Stentrode brain control interface implant
Surgical robots, such as a prototype for pediatric brain tumor surgery
Peripheral interventional devices, such as LimFlow's first-of-its-kind system, prevent amputation due to chronic limb ischemia
