Release date: 2010-01-19
When it comes to medical implants, many people may think of the steel plates and screws used for internal fixation of fractures in the first place. Austenitic stainless steel is currently used more. Austenitic stainless steel is non-magnetic, corrosion-resistant and easy to form. It is not only used for the manufacture of fracture internal fixation equipment, but also widely used in the production of artificial joints, various crowns, crown bridges, fixed brackets, implanted electrodes. , artificial heart valves, etc. However, these materials are still subject to certain problems due to their composition.
Recently, under the national “863†plan, the National Natural Science Foundation of China, the important direction of knowledge innovation of the Chinese Academy of Sciences, and the provincial and municipal funding, the Biomedical Materials and Devices Group led by the researcher Yang Ke of the Institute of Metal Research, Chinese Academy of Sciences Important progress. The new medical high-nitrogen nickel-free austenitic stainless steel developed by them has passed important biological performance tests such as cytotoxicity, hemolysis, sensitization, acute toxicity test, thrombus test and genotoxicity in the Chinese Pharmaceutical and Biological Products Testing Institute. The Military General Hospital completed an experimental study on implanted animals.
Nickel that people love and hate
Nickel is an important alloying element in medical austenitic stainless steels that are currently widely used. Yang Ke told the Science Times reporter: "The main function of it is to make stainless steel form a stable austenitic structure, thereby improving the corrosion resistance, plasticity, weldability and toughness of stainless steel, and the stable austenitic structure. The stainless steel can be made non-magnetic. The nickel content in medical 316L and 317L austenitic stainless steel is required to be 10% to 14%, and the nickel content in medical 304L stainless steel is also 8% to 10%."
However, nickel is a potential sensitizer, and a large number of clinical manifestations have shown that nickel and its compounds can cause harm to humans. The most common damage is nickel contact dermatitis, which has a high incidence, and eczema can occur in people with high allergies. "When in contact with the human body, nickel ions can penetrate into the skin through the pores and sebaceous glands, causing skin irritation and inflammation, and its clinical manifestations are dermatitis and eczema." Yang Ke said, "At present, the euro uses 1 euro and 2 euro coins. The release of nickel may cause a strong allergic reaction to the skin of people with a tendency to be allergic to nickel."
What should be more alarmed is that the enrichment of nickel ions in the organism may also induce toxic effects, cell destruction and inflammatory reactions, and teratogenic and carcinogenic hazards to the organism. When nickel-containing medical metal materials are implanted into the human body, metal ions such as nickel ions are released to adjacent tissues due to inevitable corrosion and abrasion, which is easy to induce tissue reactions such as allergies and infections, especially in patients allergic to nickel. The famous medical journal The Lancet has reported that allergic reactions caused by the release of metal ions such as nickel, chromium and molybdenum in stainless steel cardiovascular stents may be one of the indirect causes of cardiovascular stent restenosis.
It is precisely because of the harm of nickel to the human body that many countries have higher and higher requirements for the nickel content in daily and medical metal materials, and the highest nickel content allowed in the relevant standards is also getting lower and lower. In view of the possible harm to human health caused by nickel-containing medical metal materials, experts recommend that the best way is to strictly prohibit or limit the nickel content of various metal materials (such as implanted devices, dental materials, jewelry, etc.) that are in direct contact with the human body.
Scientific research on nitrogen and nickel
Yang Ke's research on medical nickel-free stainless steel began in 2000. Yang Ke said: "The goal at the time was to develop a new stainless steel material to replace the medical 316L stainless steel for cardiovascular stents and to develop a new generation of cardiovascular stents."
However, the exploration of any new technology is not smooth sailing. Yang Ke told reporters: "We have encountered many scientific problems or technical difficulties in the research process and we need to solve them."
The research and development idea of ​​the new stainless steel is to replace the nickel element with nitrogen to stabilize the austenitic structure of stainless steel. The main scientific problems brought about by this include the optimization of chemical composition of the new stainless steel (especially the optimization of nitrogen content in steel). The smelting and processing of high-nitrogen stainless steel, the influence of nitrogen on the biocompatibility of stainless steel and related mechanisms. For example, high-nitrogen nickel-free austenitic stainless steel is only a component difference compared with traditional medical stainless steel, that is, nickel is added and nitrogen is added, and the austenite structure is unchanged, but it exhibits better blood compatibility. Sex is the contribution of nitrogen addition or the effect of nickel removal. Researchers at home and abroad have not given clear conclusions.
After several years of research, Yang Ke’s team found that the first removal of nickel improved the blood compatibility of stainless steel, and with the increase of nitrogen content in steel, the blood compatibility of high-nitrogen nickel-free austenitic stainless steel Will gradually improve. Yang Ke said: "We also cooperated with the research team led by Professor Jiang Zhouhua of the School of Materials and Metallurgy, Northeastern University, to overcome the smelting problem of high-nitrogen stainless steel and obtain experimental materials with chemical composition."
According to Yang Ke, in the study, they also encountered many other difficulties, such as the need for a large amount of fresh blood in the experimental research. Because the state now has strict blood control, it needs to be repeatedly tested before being provided, so that they get a few The old blood of the day affects the experimental results. "In order to ensure the accuracy of the experiment and ensure the smooth progress of a large number of repeated experiments, in many cases, Dr. Yibin, who is specifically responsible for this project, volunteered to donate blood to complete the experiment. He has donated blood for this experiment more than 10 times." Yang Ke Say.
In the research and development process of Yang Ke team, they have successively received funding from the national “863†project, the National Natural Science Foundation of China, the important direction project of knowledge innovation of the Chinese Academy of Sciences, and the provincial and municipal areas. "It is precisely because of the support of a large amount of funds that we have been able to carry out a large amount of research and testing work, obtained a large number of experimental research results, and achieved the final success." Yang Ke said.
Looking forward to the benefit of patients in 2012
At present, the Yangke team's product development for new high-nitrogen nickel-free austenitic stainless steels is mainly concentrated in orthopedic medical devices and cardiovascular stents. The biosafety aspects of cytotoxicity, hemolysis, sensitization, acute toxicity test, thrombus test and genotoxicity of new materials developed by them have been tested in the China National Institute for the Control of Pharmaceutical and Biological Products. In addition, the micro-bone plate made of nickel-free austenitic stainless steel and medical 317L stainless steel was also used in the Guangzhou Military Region General Hospital for three months of reconstruction of the femoral fracture and internal fixation. The experimental results showed that there was no nickel austenite. Stainless steel is suitable for processing internal fixation devices such as bone plates and bone screws. Yang Ke revealed that animal experiments on nickel-free austenitic stainless steel cardiovascular stents will begin in the first half of 2010.
At present, only one US company developed medical high-nitrogen nickel-free austenitic stainless steel and a nitrogen-added low-nickel medical austenitic stainless steel developed by a Swedish company have been widely used in the European and American markets. At present, only the Institute of Metal Research of the Chinese Academy of Sciences is conducting research and development of medical nickel-free austenitic stainless steel and related medical devices, with independent intellectual property rights, and is equivalent to the international level.
Yang Ke said: "The development of nickel-free austenitic stainless steel implanted devices needs to complete the national clinical implant test after completing the animal experiment, and then obtain the trial production license and put it into clinical application. Due to clinical trials and corresponding product approval The cycle is long, and we expect to start clinical trials in 2011 and strive to gain market access in 2012."
Yang Ke pointed out that with the deepening of relevant basic research work, medical high-nitrogen nickel-free austenitic stainless steel is becoming more and more mature in material smelting and processing technology, which will certainly promote the clinical application and development of this new medical stainless steel. The new nickel-free austenitic stainless steel will have a large demand market for medical equipment, food and beverage equipment, jewelry and other stainless steel products that are in constant contact with the human body, and it is possible to gradually replace the existing nickel-containing medical stainless steel. (Source: Science Times)
Dingmin Pharmaceutical supply Amiodrone API and Amiodrone Intermediates with high purity and best price. The main products CAS No are as follows: 1951-26-4, 52490-15-0. Sample can be sent if you request.
Welcome to do business with us. Please email to us directly.
4-Hydroxy-Benzoy1,Arrhythmia Intermediates,Cas 52490-15-0
Shijiazhuang Dingmin pharmaceutical Sciences Co.,Ltd , https://www.dingminpharma.com