Brief introduction of nano silver
The particle size of nano-silver is mostly about 25 nanometers, which has a strong inhibitory and killing effect on dozens of pathogenic microorganisms such as Escherichia coli, Neisseria gonorrhoeae and Chlamydia trachomatis, and will not produce drug resistance. Cotton socks made of nano-silver and combed cotton fibers have good antibacterial and deodorizing effects.
Characteristics of nano silver
Nano-silver particles occupy an extremely important position in the field of microelectronics because of their good conductivity. The surface effect and quantum size effect of nano-silver particles make them have some special uses, such as surface-enhanced Raman applications and medical applications.
1. Nano-silver is a simple powder with a particle size less than 100nm, generally between 25 and 50 nm.
2. The properties of nano-silver are directly related to its particle size.
It was found that the smaller the particle size, the stronger the bactericidal performance.
Application field of nano silver
High-end silver paste (glue)
Paste for external electrodes of chip components, paste for thick-film integrated circuits, paste for solar panel electrodes, conductive silver paste for LED chip packaging, conductive silver paste for high-temperature sintering and oligomer conductive silver paste, conductive ink for printed electronic devices, etc.
Conductive coating
Advanced layer for filter, silver layer for magnetic tube capacitor, low-temperature sintered paste and dielectric paste.
Medical field
Antibacterial drugs and medical devices, antibacterial plastics and rubber products, antibacterial textiles and clothing shoes and socks, antibacterial coatings, ceramics and glass, green antibacterial coatings.
Green household appliances and furniture products
Antistatic and bactericidal coatings, deodorizing and antibacterial films for household appliances, etc.
Catalytic material
Catalyst for ethylene oxidation reaction, supported silver catalyst for fuel cell
new energy
Heat exchange materials, electrode materials for high-grade electronic components.
Electroplating industry
Silver coating material for electroforming gold
Product characteristics
Washing for a short time does not affect its function; Natural color, color matching, no influence on dyeing after application, and can completely replace lead-based and tin-based welding. Long-term use of nano-silver for antibacterial purposes will cause silver to deposit in organisms, which will have adverse effects on organisms and human bodies. Too much deposition can even cause obvious poisoning. The volatilization of nano-silver into the environment will also have a certain impact on the ecology and kill beneficial bacteria in the environment. After the silver nanoparticles in plastic products are precipitated, they will no longer have bactericidal effect, and the time generally ranges from three months to half a year.
Application mode
Use directly or indirectly.
product application
Nano-silver has antibacterial properties and is used in our daily life, including baby products, tableware and baby bottles. Antibacterial tableware filled with silver nanoparticles is a safe material, and phyll baby bottles (phyll silver PES education bottles, phyll silver ion PES education bottles and phyll PES combined education bottles) all contain silver nanoparticles. Nano-silver is a safe material and widely used by people.
Harm of nano silver
Seoul, South Korea's Yonhap News Agency, August 13-According to a research result, it shows the possibility that ingesting and inhaling a large amount of silver nanoparticles will harm the liver. But today, due to its excellent antibacterial effect, nano-silver is still widely used in baby bottles, toys, toothbrushes, toothpaste, air purifiers and other products.
On June 5438+02, Professor Kui Ri of hoseo university said that he and the Institute of Toxicity affiliated to the Korean Institute of Construction and Living Environment Experiment conducted animal experiments on the toxicity of ingesting silver nanoparticles and obtained the above results. However, the harm of coating on the body surface has not yet been determined, and it can be considered harmless.
Professor Sui said that the research team injected 30 mg/kg, 125 mg/kg and 500 mg/kg silver nanoparticles into mice. Results Toxic reaction occurred in the liver of mice injected with more than 125mg/kg nano-silver particles.
In addition, male mice injected with 500mg/kg showed weight loss within 4 weeks.
However, the male mice coated on the body surface did not have any adverse reactions.
Professor Wei suggested that the minimum observed dose (LOAEL) for harmful effects and the minimum observed dose (LOAEL) for adverse reactions were 125 mg/kg and 30 mg/kg respectively.
He also said:? Although it is impossible to determine whether it is harmful to human body, in the future, the government needs to formulate safety standards for the dosage of nano-silver in baby bottles, toys, textiles and packaging materials. ?
His paper? Sub-chronic oral toxicity of nano silver? Subchronic oral toxicity of silver nanoparticles was published in the British research journal on the 7th of this month? Toxicology of particles and fibers? (particle and fiber toxicology).
Antibacterial properties of nano-silver
Nanometer (nm) is the smallest unit of measurement after micron at present, and 1 nm is one millionth of a millimeter, that is, nanometer, that is, one billionth of a meter. Nano silver is a kind of nano silver. With the appearance of nanotechnology, the sterilization ability of silver in nanometer state has made a qualitative leap. A very small amount of nano-silver can produce a powerful bactericidal effect, killing more than 650 kinds of bacteria in a few minutes. It has broad-spectrum bactericidal effect, does not produce any drug resistance, can promote wound healing, cell growth and repair of damaged cells, has no toxic reaction, and has not found any irritating reaction to the skin, which opens up a broad prospect for the wide application of nano silver in antibacterial.
Broad-spectrum antibacterial agent
Nano-silver particles directly enter bacteria and combine with oxygen metabolizing enzyme (-SH) to suffocate bacteria, which can kill most microorganisms such as bacteria, fungi, molds and spores. Studies by eight authoritative institutions in China show that it has comprehensive antibacterial activity against drug-resistant pathogens such as drug-resistant Escherichia coli, drug-resistant Staphylococcus aureus, drug-resistant Pseudomonas aeruginosa, pyogenic streptococcus, drug-resistant enterococcus and anaerobic bacteria. It has bactericidal effect on common bacteria such as Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Candida albicans and other G+ and G- pathogens in burns and wounds. It also has a strong bactericidal effect on chlamydia trachomatis and Neisseria gonorrhoeae causing sexually transmitted diseases.
One antibiotic can kill about 6 pathogens, while nano silver can kill hundreds of pathogenic microorganisms. It can kill bacteria, fungi, trichomonas, chlamydia and Neisseria gonorrhoeae, and has the same bactericidal effect on antibiotic-resistant bacteria!
Strong sterilization
According to research, Ag can kill more than 650 kinds of bacteria in a few minutes. After combining with the cell wall/cell membrane of pathogenic bacteria, nano-silver particles can directly enter the bacteria and quickly combine with sulfhydryl group (-SH) of oxygen metabolizing enzyme, thus inactivating the enzyme, blocking respiratory metabolism and suffocating it. The unique sterilization mechanism enables nano-silver particles to quickly kill pathogenic bacteria at low concentration.
Strong permeability
Nano-silver particles have super permeability, can quickly penetrate into the skin for 2mm sterilization, and have a good sterilization effect on deep tissue infections caused by common bacteria, stubborn bacteria, drug-resistant bacteria and fungi.
Repair and regeneration
Nano-silver can promote wound healing, repair and regeneration of injured cells, remove putrefaction and promote granulation, resist bacteria and diminish inflammation, improve microcirculation of tissues around the wound, effectively activate and promote the growth of tissue cells, accelerate wound healing and reduce scar formation.
Antibacterial lasting
Nano-silver particles are produced by patented technology and have a protective film, which can be gradually released in the human body, so the antibacterial effect is more lasting.
No drug resistance
Nano-silver belongs to non-antibiotic bactericide: nano-silver can kill all kinds of pathogenic microorganisms, which is stronger than antibiotics. The unique antibacterial mechanism of nano-silver particles with the size of 10nm can kill bacteria quickly and directly, making them lose their reproductive ability. Therefore, it is impossible to produce the next generation of drug resistance, which can effectively avoid repeated attacks and long-term treatment due to drug resistance.
Application of silver in modern medicine
1884, German obstetrician F. Crede (Claude) dripped silver nitrate solution with the concentration of 1% into the eyes of newborns to prevent blindness caused by conjunctivitis of newborns, which reduced the incidence of infant blindness from 10% to 0.2%. Until today, Crede prevention method is still used in many countries.
1893, C. Von Nageli reported the lethal effect of metals (especially silver) on bacteria and other lower organisms for the first time after systematic research, which made it possible for silver to become a disinfectant. Since then, the utilization of silver has entered a modern period.
Silver is used in modern medicine in many forms.
First, silver salt: 0.5% silver nitrate is the standard solution for treating burns and wounds; 10-20% silver nitrate solution can be used to treat cervical erosion.
Second, silver sulfadiazine: Professor Charles L. Fox of Columbia University in the United States combined silver with sulfadiazine to make silver sulfadiazine, and its activity was at least 50 times stronger than that of sulfadiazine alone. Silver sulfadiazine was introduced into the market from 65438 to 0968. Because it can kill many kinds of bacteria and fungi efficiently, it can completely repair wounds naturally and painlessly without skin grafting, and it has become an important drug for treating trauma (such as burns). At present, it has been listed in the national basic medical insurance drug list.
Colloidal silver or silver protein: it is an effective local anti-infective substance, and colloidal silver can be used for gynecological disinfection and sterilization.
Silver-plated substance: Dr. A. B. Flick, the founder of silver research, developed a silver product, that is, a layer of silver was coated on a bandage for dressing. Inspired by him, people developed silver-plated sutures and silver-plated catheters one after another by using the antibacterial properties of silver. At present, more than a dozen silver-containing products in the United States have been approved by FDA as medical devices, including silver dressings, silver gels, silver powders and other medical products.