Use of Silver Nanoparticles

For centuries, people have used silver for its antibacterial qualities. For example, ancient Greeks cooked in silver cookware and ate with silver spoons. Generally, making objects from silver or coating them in silver can be expensive. However, scientists have developed ways to impregnate other materials with silver nanoparticles to give anything made from the materials an antimicrobial property.

Features

• Nanoparticles are particles that measure less than 100 nanometers. A nanometer is one billionth of a meter. According to AzoNano, nanoparticles usually have better or different qualities than the bulk material of the same element. In the case of silver, the antibacterial effect is greatly enhanced, and, because of their tiny size, nanoparticles have immense surface area relative to volume. Therefore, miniscule amounts of silver nanoparticles can lend antimicrobial effects to hundreds of square meters of its host material.

Function

• Bacteria, viruses and fungi all depend on an enzyme to metabolize oxygen to live. Silver interferes with the effectiveness of the enzyme in each case and disables the uptake of oxygen, thereby killing the microbe. This process has the added benefit of not harming humans. In addition, no research has discovered any bacteria able to develop an immunity to silver as they often do with antibiotics. Furthermore, silver, a naturally occurring element, is non-toxic, hypoallergenic, does not accumulate in the body to cause harm and is considered safe for the environment.

Products

• Many manufactured goods are using linings of silver nanoparticles for their antimicrobial qualities. Some of the items included are washing machines, air conditioners and refrigerators. Other items made from silver nanoparticle-impregnated substrates include sportswear, toys and baby articles, such as pacifiers, food storage containers, medical face masks, HEPA filters and laundry detergent. The medical field also is developing products with silver nanoparticles, such as heart valves and other implants, wound dressings and bandages.

  Governmental and accrediting agencies have approved these products. Organizations such as the Food and Drug Administration (FDA), the Environmental Protection Agency (EPA), Japan's SIAA, Korea's Testing and Research Institute for Chemical Industry and FITI Testing & Research Institute.

HIV

• According to the "Journal of Nanobiotechnology," scientists at the University of Texas at Austin and the Universidad Autónoma de Nuevo León in Mexico conducted a study on another important use for silver nanoparticles in 2005. They determined that silver nanoparticles of the size from one to 10 nanometers could attach to the HIV-1 virus and inhibit it from binding to host cells. This has great promise in the treatment of HIV infection.

Warning

• The so-called nano-silver industry is not without its critics, however. Michael Berger, of Nanowerk LLC, reported in 2008 that, early in 2007, the EPA issued a regulation that nano-silver lined washing machines must be registered as a pesticide. This was in part due to activist group activity demanding a ban on all nano-silver products. To study the effect of silver on the environment, a group of Singapore scientists studied the effects of silver nanoparticles on zebrafish. They concluded that zebrafish embryos exposed to such nanoparticles showed the particles in vital organs, such as the brain, and they also had severe developmental defects.