Special Metals
From traditional metals such as titanium and copper to more modern alloys like Nitinol, the metal industry continues to meet the most advanced needs in medical equipment.
Around the world, people are able to live active and long lives thanks to the continuous advancement and development of medical technology. This evolution in technology stems from the sophisticated development of metals and alloys, which have found new uses in medical applications, both internal and external. From improvements in diagnostic guides to new alloys for permanent implants in the body, metals continue to be the basis for the development of new technologies.
The metallurgical industry has a long history of innovation, development, and processing of metals and alloys in tune with the development of medical equipment, from tiny screws for the smallest implants to the most complex robotically operated surgical tools.
Titanium
Titanium is a metal known for its strong use in medical applications, particularly in internal applications. It is resistant to corrosion and also bonds with human bone when properly treated, with less likelihood of a negative reaction than other metals. Osseointegration is a unique phenomenon in which the body's natural bone and tissue bond with the titanium implant, firmly securing the implant in place.
Titanium is also a staple in the medical field, used as a shield for implanted devices that control heart function; products that dispense medication and perform neurostimulation; as well as rods, pins, and orthopedic plates.
Pure titanium is strong, has low density, and high corrosion resistance. Titanium is an excellent material when processed or formed into subassemblies or finished components. It is considered physiologically inert. Titanium alloys Ti-6AL-4V and Ti-6Al-4V ELI are especially non-reactive with human body fluids and are commonly used in medical equipment due to the low risk of rejection.
The human body accepts titanium much more easily than other metals, including stainless steel. Some of the most common uses of titanium are in orthopedic surgery (specifically in back surgery), and as a replacement for hip, knee, and shoulder and elbow joints. Some methods of heart valve replacement use titanium in housings or support rings. As a result of recent medical advances, titanium pins are used to secure eye and ear prostheses. Titanium is a standard protective material for implanted medical devices such as pacemakers and centrifuges, due to its tolerance to attack by body fluids, high strength, and low modulus.
In addition to its use in implants, titanium is the ideal choice for surgical instruments, such as drills, forceps, retractors, scissors, needle holders, and eye surgery equipment. The metal does not interfere with medical tests that require magnetic resonances or tomographies.
Niobium
There is a growing interest in niobium and its alloys for use in medical equipment. It is often found in devices such as pacemakers, as it is physiologically inert. Sodium hydroxide-treated niobium forms a porous layer that aids in osseointegration, making it an attractive alternative for internal applications.
Tantalum
This is another metal that is growing in popularity as it is highly resistant to corrosion. It has been used in medical devices as simple as diagnostic marker bands for over 50 years. Tantalum is especially useful in profiled wire applications. Its resistance to corrosion makes it attractive for implants.
Pure tantalum is ideal for use in permanent bone implants, other applications include: vascular clips, flexible stents to prevent arterial collapse, and in the repair of bone fractures. It is not ferromagnetic, therefore it is compatible with magnetic resonances.
Nitinol
Nitinol is a nickel and titanium alloy (approximately 51% Ni) with shape memory that has superelastic properties, a reversible response under stress.
Shape memory refers to Nitinol's ability to undergo deformation at a certain temperature and then recover its original shape when heated above its transformation temperature.
Nitinol's extraordinary ability to adapt to large stresses, along with its physiological and chemical compatibility with the human body, have made it a frequently sought-after material for the engineering and design of medical devices.
The "superelasticity" effect allows the use of nitinol in devices that have been bent or molded to allow their introduction or application within the body. Tools such as small gripping and biopsy devices can extend from a tube and expand to an area much larger than devices made with standard alloys.
The lightness of nitinol and its unique properties make this metal a particularly attractive material for use in biomedical applications that include tools for heart valves, stents, staples, bone anchors, sophisticated devices for septal defects, and a variety of implants. Its medical use includes devices for reconnecting intestines after surgery, such as sutures, implantable stents, diagnostic guide wires, and repositionable markers for locating breast tumors, for less invasive lumpectomy procedures in the treatment of breast cancer.
Copper
Recently, the medical industry has taken an interest in copper, which was previously off-limits for much of medical applications, especially for any internal device. The fact that copper, when properly protected, can be used to transmit signals to small implants and tools effectively, is one of the main reasons for the growing interest in this material.
Major manufacturers and processors of copper for medical devices typically produce the wire or shielded metal strips on their own equipment dedicated particularly to this material, with the purpose of maintaining high quality control and avoiding outside contamination.
Copper is a ductile metal with a high level of thermal and electrical conductivity. Pure copper is relatively soft and malleable, it's easy to work with, and the ease with which it can be transformed into wire, added to its excellent electrical properties, make copper a useful material for electrical medical devices when properly protected. Due to its high conductivity, it is possible to embed small copper wires in devices to emit or receive signals, or transport electrical charges to perform tasks within the body.
Copper ions are soluble in water, where they function at low concentration as bacteriostatic substances, fungicides, and wood preservatives. For this reason, copper can be used as a surface that repels germs, which increases the antibacterial and antimicrobial characteristics in buildings such as hospitals. Currently, its use in hospital clothing, bedding, and other products is being studied as a means to reduce the infection rate.
Quick guide to alloys and their applications:
The successful application of these metals is the result of collaborative work between manufacturers and end users, starting with the design and specifications of the material, to the finished device. The product specialists at Ulbrinox, your trusted provider, provide personalized attention to achieve the highest quality solutions. Contact us today and receive personalized advice.
Bibliography:
Ulbrich. "Special Metals Make Unparalleled Medical Devices Possible“ (2021, May) https://www.ulbrich.com/blog/s...
