Silver Nanoparticles(nanosilver)

ByChris Coulter

Main use

• Antibacterial :– Anything that destroys bacteria or suppresses

their growth or their ability to reproduce.

• Antifungal:– Anything that destroys fungi or suppresses their

growth or their ability to reproduce.

Silver uses through history.

• The Greeks used silver vessels to keep water and other liquids fresh.

• Pioneers in American found that if they placed silver or copper coins in their casks of drinking water, it kept the water safe from bacteria, algae, etc.

• Settlers in the Australian outback suspend silverware in their water tanks to retard spoilage.

• Similarly silver dollars were put in milk to keep it fresh.

• In the Middle Ages, the wealthy stored and ate their food from silver vessels to keep bacteria from growing. This protected them from the full brunt of the plague.

• Silver leaf was used to combat infection in wounds sustained by troops during World War I.

• In the early 1800s, doctors used silver sutures in surgical wounds with very successful results.

• Prior to the introduction of antibiotics, Colloidal Silver was used widely in hospitals and has been known as a antibacterial for at least 1200 years.

Applications

• Cosmetics• Odor control• Antimicrobial coatings• Burn and Wound dressing• Appliances• Filters

Soap• Silver particles penetrate

into cells and prevent the breathing of virus, bacteria, mold, and fungus, ultimately killing them.

• Antibiotics are effective against 12 kinds of bacteria at most.

• Silver can kill about 650 kinds of germs including viruses that are unaffected by antibiotics.

Odor Control- kills bacteria that cause odor –Effective against athletes foot?

Deodorant Socks and insoles

Antimicrobial coatings- Effective against resistant strains of bacteria -

• Keyboards• Phones• Appliances• Handrails• Doorknobs• Toilet seats

– In Hong Kong a Nano Silver-Titanium Dioxide coating (NSTDC) has been certified as effective in killing a wide range of bacteria, viruses and mold including the H1N1 flu virus. This coating will be applied to all surfaces touched in the Hong Kong metro rail system.

• Paint– A research group at the City College

of NY working with Rice University in Houston developed an antibacterial paint.

– They tested it by leaving E.Coli overnight on a plain glass slide, one coated with regular paint, and one coated with nanosilver paint.• The nanosilver paint coated slide

killed all of the bacteria.– This can be used in hospitals to

cover counters and walls where there is a high risk of spreading germs.

– Also very useful in homes.• Especially in bathrooms to keep germs

and mold from breeding.

Burn and Wound Dressing• Burns are very susceptable

to bacterial infections.• Current silver burn gel

contains enough silver to cause toxic effects.– Nano based silver burn gel

contains 30 times less silver. Doesn’t cause the side effects (skin discoloration and cell damage) while still being effective against drug resistant microbes.

• Blood Clotters.

AppliancesSamsung Silver Nano Washing Machine and Refrigerator.

Silver ions released during wash and rinse cycles

Clothes become antibacterial: killing odor caused by sweat or fungus for up to 30 days

Samsung Silver Nano refrigeratorA Silver Nano coating to the inner surfaces of refrigerator cause an anti-bacterial and anti-fungal effect.

As air circulates, the coated surfaces allow the silver ions to kill the airborne bacteria.

Filters• Cotton cloth dipped in a

solution of silver nanowires and carbon nanotubes.

• An electrical current supplied by a small solar panel kills 98% of bacteria in a single pass.

• Filters about 80,000 times faster than filters that trap bacteria.

• Also used in air filters to improve effectiveness.

Problems and fears

• Silver itself is classified as an environmental hazard by EPA because it is more toxic to aquatic plants and animals than any metal except mercury.– Nanosilver particles are small enough to cross through

egg membranes and into fish embryos.• Wastewater

– Silver nanoparticles destroy the benign species of bacteria that are used for wastewater treatment.

– Silver nanoparticles may become concentrated over time.– Tests are being conducted to see long term effects.

Other uses

• Nano silver paste and ink– Printed Circuit Boards (PCB).

• Low cost• Bendable

• Paper Batteries– Small– Durable– Long lasting– Can be crumpled or folded with no loss of performance

Paper Batteries• One dimensional structure helps

ink stick strongly.• Paper super-capacitors may last

through 40,000 charge-discharge cycles.– At least 10 times more than

lithium batteries.• The high surface to volume ratio

of paper gives it an advantage in uses like hybrid and electric cars because of it’s quick transfer of electricity.

• Can be made into a paint to make walls into a battery.

Any Questions?