Hippocrates, the “father of medicine”, advocated the sprinkling of silver powder on ulcers to expedite healing, and silver has been used since World War I (and continues to be used) in wound dressings.
Pencils or sticks of hardened silver nitrate (lunar caustic or lapis infernalis) were considered essential items in a surgeon’s chest as early as the 1600s and silver nitrate solutions were used to treat burn victims of the Hindenberg disaster.
Though the use of silver as an antimicrobial temporarily fell out of favor after the proliferation of chemicals such as Penicillin, interest was revived in the 1960s and silver-based pharmaceuticals continue to be used today as topical and ophthalmic disinfectants.
Silver sulfadiazine is still considered the treatment of choice for burn victims
Silver has numerous advantages over other antimicrobial agents.
Compared to molecular antimicrobials, which are generally targeted to specific organism classes, silver is broad spectrum and toxic (to varying degrees) to numerous strains of bacteria, fungi, algae, and possibly some viruses. Being an element, silver is shelf stable for long periods of time.
Conventional wisdom regards silver as safe to humans and other higher order organisms when used responsibly, and silver-based pharmaceuticals have few if any acute or chronic known side-effects at FDA-permitted doses.
Silver is reasonably effective at penetrating biofilms, which has been a drawback to many molecular antimicrobials.
Furthermore, though bacterial strains which manifest silver-resistance are known and these mechanisms have been studied, some researchers have suggested that silver may be less susceptible to the buildup of resistance than molecular antimicrobials.
This remains an area of some uncertainty. Even so, however, the explosion of interest in silver as a broad-spectrum antimicrobial agent during the last two decades may be in part due to the proliferation of resistance to strong molecular antimicrobials; in that respect, silver has been shown to be an effective bacteriocide against antimicrobial-resistant bacterial strains (e.g., MRSA), which have become a concern in hospitals.
Yet perhaps the largest advantage of silver antimicrobials is that silver can be easily incorporated into numerous materials such as textiles and plastics, making it especially useful for applications where broad spectrum, sustained antimicrobial activity is desirable but where traditional antimicrobials would be impractical.
This is not only advantageous to the food industry, where silver-containing plastics have been incorporated into everything from refrigerator liners [189] to cutting boards to food storage containers, but it has also been revolutionary to the medical device industry, which has seen a proliferation of silver-coated urinary catheters, cardiovascular implants, esophageal tubes, bandages, sutures and other instruments on which bacterial growth compromises patient survival.
To date, the FDA has approved over a dozen silver-containing zeolites or other substances for use as food contact materials4 for the purpose of disinfection, as well as numerous silver-coated medical devices.