The use of silver for medicinal purposes is far from new, and in fact stretches back thousands of years. The precious metal has been used to treat ailments ranging from skin ulcers to bad breath, as well as to preserve liquids and purify water. But after the 1940s, when doctors began using anti-bacterial drug agents, the medicinal use of silver largely declined. With the release of the new study, published last week in Science Translational Monthly, this may change. The BU and Harvard researchers examined how the use of small amounts of silver affected bacteria known as Gram-negative, which have an extra protective membrane that makes them more resistant to antibiotics. When combined with the common antibiotic vancomycin and injected into mice that had been infected with Gram-negative E. coli bacteria, silver helped the drug in two ways: by breaking down that protective layer around the bacteria, and by interfering with the pathogen’s metabolism, triggering the production of bacteria-damaging reactive oxygen molecules. Though the experiments were performed on mice, and much more testing is required before similar treatments can be used on humans, the study suggest exciting possibilities for silver’s ability to aid in the fight against newly developing “super bugs,” or multi-drug-resistant microbes that pose such a frightening threat to our health.
The use of silver plates or vessels dates back as far back as ancient Mesopotamia, or around 2500 B.C., and cultures around the world boast their own long traditions of finely crafted silver utensils. The widespread appearance of silver cooking and eating utensils on the dining tables of history’s wealthier classes has spawned more than one idiomatic expression. In the early 19th century, the description “born with a silver spoon in one’s mouth” was coined to refer to someone born into wealth and privilege. The ingestion of too much silver is known to cause a condition called argyria, which turns the skin a blue-gray color permanently. As well-to-do families throughout history have undoubtedly ingested some of the previous metal along with their food and drink, the fact that argyria was typically more common among the upper classes may explain the origins of the term “blue bloods.”
In classical photography, film is covered with silver compounds, or halides, which set when exposed to light, revealing the captured image. Though it’s relatively expensive, a satisfactory substitute has never been found. Until the recent introduction of digital cameras, the use of silver-based film had steadily increased since the early development of photography in the early to mid-19th century.
Silver has the highest degree of reflectivity of all the elements, and is able to reflect up to 95 percent of visible light. For this reason, it is used extensively in mirrors and other reflective surfaces, including solar panels designed to deflect external heat from the sun in order to maintain internal temperatures. Silver is also often incorporated into automobile windshields and sunglasses, in order to moderate glare.
In a relatively new use of the precious metal, nanoparticles of silver are being incorporated into a variety of textiles and consumer clothing products, especially those designed for active wear, to prevent the smell of perspiration. The environmental impact of such usage is still being determined, however: When clothes treated with silver are washed, the nanoparticles release silver ions that cannot be broken down in nature, and are toxic to many organisms.