Inventory Of Medical Metal Materials

According to the classification of biomedical materials, the previous two viewpoint articles have elaborated on medical polymer materials and bioceramic materials. This article will focus on the third type of biomedical materials - medical metal materials. Medical metal materials play an extremely important role in the field of modern medicine. With their unique mechanical properties and biocompatibility, they are widely used in many fields such as orthopedics, cardiovascular, dentistry and surgery. This article will discuss in detail the definition, classification, application status and future development trend of medical metal materials, and summarize their contributions in the medical field. 01 Medical Metal Materials
Medical metal materials refer to metals and their alloys specifically used in the medical field. They are usually used to manufacture medical devices and implants that are in direct contact with the human body, such as artificial joints, fracture fixation devices, heart valves, dental implants, etc. Its unique requirements mainly include: good mechanical properties, biocompatibility, corrosion resistance and stability. Mechanical properties are the basic requirements of medical metal materials. They must have sufficient strength and toughness to withstand various physical stresses inside and outside the human body. Biocompatibility is a key factor in ensuring the safe use of metal materials in the human body. Materials with good biocompatibility will not cause obvious immune response, inflammatory response or other adverse physiological reactions when in contact with biological tissues. Corrosion resistance is an important indicator of medical metal materials because the internal environment of the human body is complex and corrosive. The body fluids in the human body are rich in various ions and molecules, and these chemicals may corrode metals. Therefore, medical metal materials must remain stable in such an environment and not undergo electrochemical corrosion.
02 Classification of medical metal materials
Medical metal materials can be mainly divided into stainless steel, titanium and its alloys, cobalt-chromium alloys, precious metals and magnesium alloys according to their chemical composition and application scenarios.
1 Stainless steel
Stainless steel is one of the earliest metal materials used in the medical field and has good mechanical properties and corrosion resistance. 316L stainless steel is particularly common in medical applications due to its low carbon content and added molybdenum. It is commonly used to manufacture surgical instruments, bone plates and screws. Although stainless steel is relatively cheap and has good processability, its corrosion resistance and biocompatibility still need to be improved in long-term implant applications.
2 Titanium and its alloys
Titanium alloy is one of the most widely used medical metal materials. Titanium has low density, high strength, good corrosion resistance, and a similar elastic modulus to human bone tissue, so it is widely used in orthopedic implants such as hip and knee replacements. Ti-6Al-4V is the most common titanium alloy, and it has become the preferred material for orthopedic surgery due to its excellent mechanical properties and biocompatibility. However, one disadvantage of titanium alloys is its high price and difficulty in processing.
3 Cobalt-chromium alloys
Cobalt-chromium alloys have extremely high strength and excellent wear resistance, and are suitable for medical devices that need to withstand high loads and wear for a long time, such as artificial joints and dental restorations. The high hardness and corrosion resistance of cobalt-chromium alloys give it an advantage in the field of implants, but its high elastic modulus may lead to a "stress shielding effect", that is, the implant bears too much stress, reducing the load on the surrounding bone tissue, which may affect the healthy growth of bones.
4 Precious metals
Such as gold, silver, platinum, etc., due to their excellent biocompatibility and corrosion resistance, are often used in some special medical applications, such as pacemaker electrodes and dental restoration materials. However, due to their high prices and limited mechanical properties, the use of precious metals is subject to certain restrictions.
5 Magnesium alloy
Magnesium alloy is a new type of biodegradable metal material. It is becoming a research hotspot due to its excellent mechanical properties and biocompatibility. The density and elastic modulus of magnesium are similar to those of human bones. It can be gradually degraded in the body and eventually absorbed by the body, avoiding the need for secondary surgery to remove it. However, the rapid degradability and hydrogen release of magnesium alloys still need to be further resolved.
03 Application of medical metal materials
Medical metal materials are widely used in various medical fields due to their excellent performance, including orthopedics, cardiovascular, dentistry, neurosurgery and other surgical fields.
1 Orthopedic applications
In the field of orthopedics, medical metal materials are mainly used to manufacture fracture fixation devices, artificial joints, spinal fixation devices, etc. Titanium alloys are widely used in hip and knee replacements due to their excellent biocompatibility and mechanical properties. Cobalt-chromium alloys are often used on the surface of artificial joints due to their wear resistance and high hardness. In recent years, the research progress of magnesium alloys has shown its potential as a bone fixation material, especially in the treatment of pediatric fractures, which can avoid the need for secondary surgery.
2 Cardiovascular applications
In the cardiovascular field, stainless steel and cobalt-chromium alloys are often used to manufacture implants such as vascular stents and heart valves. Vascular stents need to have high strength, corrosion resistance and good biocompatibility to prevent restenosis or blockage of blood vessels. Stainless steel stents were once widely used because of their low cost and easy processing, but because they may cause restenosis in the stent, most stent materials are currently turning to cobalt-chromium alloys or drug-coated stents.
3 Dental applications
In the dental field, titanium and its alloys are widely used in dental implants because they have good biocompatibility and can form a strong bone bond in the alveolar bone. In addition, cobalt-chromium alloys are also widely used in dental restoration materials such as crowns and bridges because of their corrosion resistance and wear resistance.
4 Other surgical applications
Medical metal materials are also widely used in other surgical fields, such as skull repair plates in neurosurgery, prostheses in plastic surgery, and the manufacture of surgical instruments. Stainless steel is still the main material for the manufacture of surgical instruments due to its good mechanical properties and corrosion resistance.
04 Future prospects and summary
Medical metal materials have an irreplaceable position in modern medicine. With the continuous advancement of science and technology and the increasing requirements of people for medical effects, medical metal materials will continue to develop to meet the challenges of different medical needs. Future research will focus on improving biocompatibility, optimizing mechanical properties, developing new materials, and achieving multifunctionality to provide patients with safer and more effective treatment options. In summary, the development of medical metal materials not only depends on the progress of materials science and engineering, but also needs to be cross-integrated with biomedicine, clinical medicine and other disciplines to form a comprehensive research platform. In the future, with the emergence of more new materials and technologies, medical metal materials will show broad application prospects in more fields and make greater contributions to medical progress and human health.