Silver has been known since ancient times – but not just to make jewelry, tableware, utensils, or silver coins. The metal has also been used as an antiseptic and disinfectant. More than 2000 years ago, Hippocrates, the father of modern medicine, wrote that silver had beneficial healing and anti-disease properties. And during World War I, silver compounds were still being used to prevent infections. It was only with the development of modern antibiotics, that the widespread use of silver went out of fashion. But now it seems as if the precious metal is experiencing a medical renaissance.
As reported in The Chemical Engineer, researchers from the Swiss Federal Institute of Technology were able to create a covered plastic film that they claim is up to 1000 times more effective in killing Escherichia coli bacteria cells than conventional silicon-based methods. They are also saying that the polymer film only releases silver nanoparticles if bacteria are growing in the vicinity. The chemical engineers discovered that coating a plastic film with a mix of silver and calcium phosphate nano-particles proves deadly to bacteria. While it had previously been impossible to apply silver in a targeted and measured way, the problem now seems to have been overcome by using a polymer film and applying the silver to the calcium phosphate. According to Wendelin Stark, a chemical engineer and leader of the project, this method is easy to apply and could bring great benefits to patients in hospitals.
And this is how it works:
Bacteria rely on calcium for their metabolism, so the 20 to 50 nanometer calcium phosphate particles are used by the microorganisms as nutrition. When the bacteria consume the calcium phosphate, thousands of silver particles are being released. These tiny silver particles then kill the bacteria by preventing the cell’s nutrient transport, attacking the cell membrane, and interfering with cell division.
It seems as if nanotechnology has allowed the chemical element somewhat of a medical revival!Yvonne Klöpping