Silver Nanoparticles ( nanosilver)

1. Silver Nanoparticles(nanosilver) By Chris Coulter

2. 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.

3. 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.

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

5. 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.

6. Odor Control- kills bacteria that cause odor –Effective against athletes foot? Deodorant Socks and insoles

7. 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.

8. 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.

9. 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

10. Samsung Silver Nano refrigerator A 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.

11. 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.

12. 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.

13. 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

16. 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.

17. Any Questions?