Silver has been used for centuries to kill germs and prevent infection. Now, advances in nanoscience (the manipulation of chemical and biological materials with dimensions from 1-100 nanometers) have allowed researchers to develop a new kind of silver: silver nanoparticles. These tiny particles are able to invade bacteria and other microorganisms and kill them without harming healthy cells.
Because of their unique properties, these nanoparticles are widely impregnated into a variety of consumer products, such as textiles (including socks, sportswear and bedding), shoes, vacuum cleaners, washing machines and toys. However, when these products are laundered, the silver releases into wastewater and the environment. This release is particularly harmful to microbes that are essential for ecological systems.
Recently, the United States worked with federal agencies to halt the sale of unapproved “nano silver” products touted as COVID-19 treatments. In a civil complaint filed in the District of New Jersey, the government alleged that Natural Solutions Foundation, Rima Laibow, and Ralph Fucetola sold and distributed a product that they falsely represented would cure, mitigate, treat, or prevent the spread of COVID-19.
The cytotoxicity of nano silver varies according to the concentration, size, and surface functionalization of the silver particles and the type of body cell in which they are introduced. Fortunately, several approaches to modify the internal toxicity of nano silver have been developed in recent years, including the use of different stabilizing agents and size-modified nano silver. This article provides an overview of these developments.