Silver Is a Girl's Best Friend?

Shining the way for new antimicrobial methods.

Silver has long been valued as a precious metal, and it has been used in currency throughout many civilizations in the past and present. It has the highest conductivity of electricity and heat and the highest reflectivity of all metals. But alongside its obvious shiny aesthetic properties, it has also been used in diluted silver nitrate forms in disinfectants, added to bandages, catheters, and other medical instruments. In fact, in 2008 the ACTICOAT dressing with silver infused into it was developed for use on burns to eliminate infection and still be safe for patients with damaged immune systems. ACTICOAT was even found to eliminate MRSA within 30 minutes in laboratory tests!

If only just rubbing a silver coin on your burn had the same effect!

One of the rising concerns of modern medicine is antibiotic resistance among viral and bacterial species. As scary as it sounds, those hand sanitizers outside hospitals just won’t be enough in the near future. Current antibiotics mainly work by destroying a bacteria’s outer membrane in a method known as lysis. However, bacteria can strengthen their membranes to prevent this.

Biofilm Breakup!

Studies on biofilms, which are groups of hardy bacteria that can form anywhere from the inside of pipes to the bottom of ships, show that adding silver to existing antimicrobial treatments kills off 100x more bacteria than antibiotics alone! Silver also kills dual species biofilms, where bacteria such as E. Coli and Staphylococcus Aureus for example, have banded together to increase the infectivity and pathogenicity of the biofilms.

In fact in 2017, Sportelli et al mixed the ever advancing field of biomaterials with silver in the development of a biofilm made from nanoparticles of Teflon with imbedded silver. Silver ions were released from the teflon, causing bacterial cell stress, membrane collapse and lysing, or cutting, of the cell membrane. This of course killed off bacteria and stopped biofilms forming.

The antimicrobial effect of silver doped nanoparticles has been incorporated into modern medicine in a variety of different methods. Silver doped nanoparticles could prevent E. Coli, Staphylococcus Aureus, and Pseudomonas aeruginosa; common causes of stomach infections and UTI's, with bigger particles exhibiting a wider area of effect. Catheters and medical equipment have been dipped in these nanoparticles for some time now, but in 2017 PhD student Aiste Lisauskaite and her supervisor Dr. Virginija Jankauskaite at Kaunas University of Technologyhave found a way to infuse silicone with silver to massively increase its antimicrobial effect.

However, the rampant use of silver in everyday items, such as toothpaste, dressings, household appliances, etc., could eventually put the broad-spectrum effectiveness of silver at risk. Silver is already in food packaging to extend product life and there is even silver infused wound gel. So does the fight against superbugs lie with silver? 

Is it all safe and sound?

Well, there are some downsides—silver can stain the skin around the wound if used in a gel or dressing. However, this is not harmful and purely cosmetic, so if you don't mind momentarily resembling the silver surfer, it's not too much of a problem. However, as with many cell-killing cytotoxic treatments, silver can destroy host cells as well in very rare occasions leading to bone marrow toxicity due to silver ions deposited in the bone. Also prolonged exposure to bioactive silver delivered in nanoparticles in the body could cause microbial resistance to eventually become a problem again! However, with the field of biomaterials progressing every day and antimicrobial research constantly improving, there may be a sure future of silver being used in modern medicine.

There are already studies into the development of silver infused hospital gowns which will be more antibacterial and more reusable, needed only a wash to be ready to use again, with its antimicrobial properties still intact. Although they will eventually need replacing after a long while, it will save the hundreds of gowns ending up on landfill every day. However, as with all new research, more work needs to be done to make these gowns safe for the environment when they are eventually disposed of.

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Silver Is a Girl's Best Friend?
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