Antimicrobial Nanoparticle Silver Coatings

The Silver Bullet

In ancient times water was observed to stay fresh for longer periods of time in Ag vessels, or if Ag coins had been added. Ag itself is impressive antimicrobial, even in comparison to potent antibiotics. Due to multiple mechanism of action bacteria are less prone to developing immunity. However, with the advent of penicillin and antibiotics silver became less used.

How Silver Nanoparticles Work Against Microbes

When silver is reduced to nanoparticles, its surface area increases dramatically, enhancing its ability to interact with and destroy bacteria, viruses, and fungi. Sputter deposited silver tends to form islands, which size and dencity can be controlled by alloying or additional seed layer.

These tiny particles release silver ions that:

• Destabilizing bacterial cell walls, disrupting their structure

• Penetrate cells and interfere with vital functions like respiration and inhibit DNA replication

• Generate reactive oxygen species that damage cellular components

  
  

Sputtered nanoparticle silver is proven effective against over 150 bacterial strains including nine clinical isolates of multiple antibiotic resistant bacteria, such as MRSA and VRE as well as six clinical fungal isolates. Another characteristic of sputtered nanoparticle silver is its ability to rapidly kill bacteria, relative to other antimicrobials.

In contact with a wound the sputtered nanoparticle silver coating releases a sufficient level of silver to kill bacteria and continue to do so for prolonged periods without removal of dressing. Reseach has demonstrated that nanoparticle silver does not have negative effect on wound but acts as an anti-inflammatory agent.

Finally, nanoparticle silver has been shown to induce apoptosis, a body's way of disposing damaged, infected, or inflammatory cells without causing damage or stress to neighbouring cells. In comparison to steroids or immunosupressants, nanoparticle silver is not known to have any serious side effects or long term issues. For example, studies have shown that silver-coated catheters reduce urinary tract infections by up to 50%, demonstrating clinical benefits.

Advantages of sputtering

Sputtering is a low temperature process in which temperature sensitive substrates can be processed and it allows to form nanometer level materials without re-crystallization and process can be tuned to specific substrate by optimizing processing parameters such as pressure and power.

Antimicrobial nanoparticle silver coating can be applied to a wide range of surfaces, filter medias and devices by sputtering as an transparent or thicker layers. Healthcare facilities aiming to improve infection control can explore antimicrobial nanoparticle silver coatings as part of their strategy. Combining this technology with standard hygiene practices can create safer environments, silver coatings may become a standard feature in medical devices and hospital infrastructure.

Facilities interested in adopting this technology can consult with material science and vacuum coating experts to select appropriate manufacturing technology and proper application methods.