1. The antibacterial effects of silver nanoparticles have been proven
Since ancient times, silver has been recognized as having antibacterial properties. The ancient Romans used silver pots, and cutlery was made of silver. In the past, silver coins were added to milk to reduce acidity. Storing milk in silver cups can increase the shelf life of milk. In recent times, silver nanoparticles has been used in bandages to aid in healing and prevent infection, as well as a variety of other applications such as incorporation into surfaces of utensils used in the kitchen, hospital. It is also added to fabrics to create antibacterial fabrics, mixed with paint to produce antibacterial paints, or added some additives to make preparations in the prevention and treatment of aquatic, animal, and agricultural diseases. karma is caused by bacteria, viruses, and fungi.
One research paper states that silver is effective against 650 strains of microorganisms.
2. How does silver nanoparticles kill bacteria?
This is still a hotly debated topic and more research is needed. There are many studies conducted to explain the bactericidal mechanism of nanosilver but mainly there are 2 main directions to explain.
The first point of view: The redox silver nanoparticles produce silver ions, the Ag + silver ions disrupt the cell membrane leading to the death of the organism. (Chemical mechanism)
The second point of view: At the nanometer size, silver nanoparticles easily pass through the cell wall of bacteria, leaking the intracellular components of bacteria (the internal components of bacteria such as DNA, riboxome, mitochondria … ) the word is fatal. (Physical mechanism)
The problem here is the quick or slow delivery of silver ions, as solutions of silver ions (soluble silver salts) ingested in the body become precipitated silver compounds (silver salts) within seconds. Silver nanoparticles take longer to produce silver ions from their surface.
This oxidation is slower than the direct ions exposure method, but in the case of possible free ions such as chloride (serum, etc.), silver nanoparticles are the mechanism for the generation of silver ions. results due to their low reactivity potential. Whether their antibacterial properties derive from the actual seeds or their ability to release ions, the results are the same.
3. What are the advantages and disadvantages of colloidal silver compared to ionic silver solution?
While silver ions have proved useful in external applications such as antiseptic. However, when introduced into the body, silver ions are limited by their reactivity. The reason is that silver compounds are produced ineffectively and or cause undesirable effects in high doses (such as cytotoxicity).
Silver nanoparticles (colloidal silver) solutions do not suffer from this disadvantage because they do not easily form compounds in humans and animals. The amount of silver ions secreted slowly is both non-toxic and has a long-lasting bactericidal effect.
4. Nanoparticle size affects reactivity
Particle size also plays an important role when it is involved in the reaction of silver nanoparticles. The ability to release silver ions (Ag +) of silver nanoparticles only occurs on the particle surface. Therefore, for any given particle weight, the smaller the particle, the greater the total surface area.
It was shown that silver nanoparticles with a smaller particle size demonstrated a greater ability to release silver ions. Even in the case where the actual exposure of the particles can be demonstrated as the reaction mechanism, the surface area remains the dominant factor determining efficiency.