Antibacterial coating nano silver is regarded as a new generation of antibacterial agents and has great potential to be utilized in antibacterial surface coatings for medical devices, food package and industrial pipes. However, disadvantages such as easy aggregation, uncontrollable release of silver ions and potential cytotoxicity greatly hinder its uses. Recently, polymers possessing unique functions have been employed to fabricate nanocomposite coatings with nanosilver for better biocompatibility and enhanced antibacterial activity. This review starts with progress on antibacterial mechanism and cytotoxic effects of nanosilver. Antibacterial functions of polymers are subsequently discussed. Advances of fabrication of polymer/nanosilver composite coatings for antibacterial applications are surveyed. Finally, conclusions and perspectives, in particular future directions of polymer/nanosilver composite coatings for antibacterial applications are proposed. It is expected that this review is able to provide the updated accomplishments of the polymer/nanosilver composite coatings for antibacterial applications while attracting great interest of research and development in this area.
Nanometer (nm) is the second smallest micron unit of measurement, a nanometer is a millionth millimeter, namely nanometer, which is one billionth of a meter. Nano-silver is the use of cutting-edge nanotechnology silver nano, nanotechnology have enabled the state of nano silver sterilization ability to produce a qualitative leap, little nanosilver can have a strong bactericidal effect, can kill in minutes Death 650 kinds of bacteria, broad-spectrum bactericidal without any resistance, to promote wound healing, cell growth and repair of damaged cells without any toxicity, skin irritation also did not find any, which gives wide Application to antibacterial nano silver has opened up broad prospects, is the latest generation of natural antibacterial agent, nano-silver sterilization has the following characteristics:
Broad-spectrum antibiotic
Silver nanoparticles directly into the cell and oxygen metabolizing enzymes (-SH) combine to make cell suffocated unique mechanism of action, can kill most bacteria in contact with, fungi, mold spores and other microorganisms. After eight domestic authorities found: their drug-resistant pathogens, such as E. coli, resistant Staphylococcus aureus resistant Pseudomonas aeruginosa, Streptococcus pyogenes resistant enterococci, anaerobic bacteria, which are full of antibacterial activity; surface burns and trauma of common bacteria such as Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Candida albicans and other G +, G- pathogens have a bactericidal effect; Chlamydia trachomatis, a sexually transmitted disease caused by Neisseria gonorrhoeae also has a strong bactericidal effect.
An antibiotic can kill about six kinds of pathogens, and nano-silver can kill hundreds of pathogenic microorganisms. Kill bacteria, fungi, trichomoniasis, branch / chlamydia, gonorrhea, strong bactericidal effect of antibiotic resistant bacteria have the same role in the killing!
Potent bactericidal
It found, Ag 650 kinds of bacteria can kill within minutes. Nano silver particles and pathogens in the cell wall / membrane-bound, directly into the cell and quickly combine with oxygen metabolizing enzyme thiol group (-SH), inactivating the enzyme, blocking the respiratory metabolism to suffocate it. Unique sterilization mechanism, making silver nanoparticles at low concentrations can rapidly kill pathogens.
Permeable
Silver nanoparticles with superior permeability, can rapidly penetrate the subcutaneous 2mm sterilization, common bacteria, stubborn bacteria, resistant bacteria as well as the deeper tissue infections caused by fungi have a good bactericidal effect.
Repair and regeneration
Nano-silver can promote wound healing, promoting repair and regeneration of damaged cells, to rot myogenic, anti-inflammatory improve microcirculation trauma to surrounding tissue, effectively activate and promote the growth of tissue cells, accelerate wound healing and reduce scarring generated.
Antibacterial lasting
Silver nanoparticles use patented technology, outer layer of protective film can be gradually released in the human body, so anti-bacterial effect.
No drug resistance
Nano-silver is a non-antibiotic agents: nano-silver can kill a variety of pathogenic microorganisms, more than antibiotics, antibacterial mechanism of silver nanoparticles unique 10nm size can quickly kill bacteria directly to the loss of reproductive ability, therefore, can not produce the next generation of drug resistance, can effectively avoid drug resistance and cause recurrent permanently.
Silver used in modern medicine
In 1884, the German obstetrician F. Crede (Claude), the concentration of 1% silver nitrate solution was dropped in the eyes of newborns to prevent blindness caused by neonatal conjunctivitis, infant blindness prevalence dropped from 10% 0.2 percent, until today, many countries still using Crede prophylaxis.
In 1893, C. Von Nageli (Nag column) through a systematic study, first reported in the metal (especially silver) bacteria and other lower organisms lethal effect, so there may be a silver disinfectant. Since then, the use of silver into the modern era.
Silver used in modern medicine in many forms, including:
(1) silver: 0.5% silver nitrate standard solution for treating burns and wounds; 10-20% of the silver nitrate solution applied, can be used for the treatment of cervical erosion.
(2) Silver sulfadiazine: Columbia University Charles L. Fox (Fox) professor and sulfadiazine silver compound, silver sulfadiazine generated activity than the individual sulfa strong activity at least 50 times. 1968, silver sulfadiazine (Sulfadiazine Silver) introduced to the market, because of its variety of bacteria, fungi and efficient role in the killing has, naturally, painless way to fully repair the wound site without skin grafting, has become the treatment of trauma ( such as burn) important drugs. It has now been included in the national basic medical insurance drug list.
(3) colloidal silver or silver protein: an effective topical anti-infective substances, colloidal silver can be used for gynecological sterilization.
(4) silver plated materials: silver, founder of the research, AB Flick (Fleck), Dr. Silver has developed a product that is coated with a layer of silver on the bandage, used as a dressing. Inspired by him, people use silver antimicrobial resistance, have developed a silver-plated sutures, silver catheter. Currently the United States has a dozen silver-containing products, as a medical device received FDA marketing approval, including silver dressings, silver gelatin, silver powder and other types of medical products.
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