Silver metal in its pure state does not exert any antimicrobial property. However, its ionic form Ag+ is potent antimicrobial agent against all lower forms of life – bacteria, fungi, yeasts and viruses. Though, Silver’s antimicrobial characteristics have been empirically known for centuries to ancient Europeans and Asians, it wasn’t until the late 19th century that silver nitrate in 1% eye drops was first used in modern medicine as prophylactic to treat to babies (born to mothers with venereal diseases) to reduce the risk of blindness from Chlymadia trachomatis bacteria infection.

Despite its potent antimicrobial property and without the risk of microbes developing resistance to it, silver containing products are not as widespread. That is because in products silver must be included as ionic silver which is both light and heat sensitive. Thus, formulating products during manufacturing becomes risky as process steps often involve incidental light and heat exposure which turns ionic silver to elemental silver rendering it ineffective and discolored.

With the advent of antibiotics in the 20th century, use of silver-based products fell out of favor until silver sulfadiazine emerged as the drug of choice in 1970s for preventing and treating sepsis in burn patients. Thereafter, a plethora of silver containing products such as gels, non-woven dressings etc. were introduced, finding varying degrees of success. However, the light and heat sensitivity issue with ionic silver still limited its broader acceptance.

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With the overuse of antibiotics in the last fifty years, researchers and formulators have begun paying attention to antimicrobial silver, because of the rapid emergence of antibiotic resistant microbes. A recent article estimated that in 2019 globally 5 million succumbed to death without effective antibiotic against these strains. Even more alarming is their estimate that in 2050, the death count could rise as high as 20 million!

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For more widespread acceptance of silver-based products, the antimicrobial power of ionic silver must be harnessed in a way that ionic silver remains stable and effective. Thus, the holy grail in antimicrobial silver technology is the one where the ionic silver remains practically indefinitely stable against light and heat. 

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The current best in the class antimicrobial silver compound stable to light and heat is silver sulfadiazine. However, due to its toxicity issues, it has never found widespread use outside its indication in sepsis prevention in burns treatment.