Chemists from the Nanoco company in the southern city of Tarnowskie Góry have developed a new biocide called Nano Silver that combines the bactericidal properties of silver with the vast opportunities offered by nanotechnology.

The CLO Burn Treatment Center in Siemianowice ¦l±skie, in the Silesia region, has given the thumbs-up to the new product.

International statistics show that hospital-related infections kill more people than car accidents. Bacteria keep mutating, becoming immune to new biocides, which explains why many doctors as well as patients have long dreamed of a product that would ensure lasting sterility to disinfected surfaces. There is every indication that this dream has now come true-thanks to Nano Silver.

In addition to Nano Silver, the Nanoco company has developed new methods for the production of bactericides, fungicides, deodorizing agents and bactericidal polymers. All these methods rely on the use of nanosilver, or silver molecules that are the size of one-millionth of a millimeter. The molecules are suspended in water and can only be seen under an electron microscope. Applied to any surface, the biocide kills all microorganisms from bacteria to fungi.

Tests at the CLO have proved that nanosilver kills bacteria immediately. Spraying it on the walls and floors in the rooms where patients stayed, as well in the bathrooms, kept the surfaces free from pathogenic microorganisms for as long as 14 days. Such a lasting effect results from the fact that microorganisms are unable to develop immunity to silver. This is particularly significant in fighting antibiotic-resistant bacteria strains that plague hospitals, such as Staphylococcus aureus, Salmonella typhi, Klebsiella pneumoniae, Neisseria or streptococci. Silver is effective in the case of 99.9 percent of bacteria and fungi.

Invisible but mighty
The germicidal properties of silver were used 6,000 years ago by the Sumers who kept water in silver pots so that it could stay fresh for longer, and dropped silver coins into pots with milk to prevent it from going bad. During great epidemics, people who used silverware were more likely to survive. Small children were fed with silver spoons in order to boost their immunity. Wounds were treated with silver compounds that accelerated healing.

However, only the development of nanotechnology has enabled scientists to make full use of silver's germicidal properties. With its molecules broken down to nano size, researchers have achieved a much larger active surface, and unprecedented bactericidal power. One gram of silver, fragmented down to nano scale, has an active surface of hundreds of square meters.

The silver nanomolecule is effective for as long as it stays on the surface, that is, unless it is removed mechanically. However, the natural appearance of dust or washing may weaken its germicidal effect with time.

There are already many germicidal cleaning agents on the market that contain silver, but their effectiveness varies. A high concentration of silver ions is of crucial importance, so many companies have sought technologies to develop agents with high silver ion concentration. Nanoco has left all of them behind.

"At first, we obtained nanosilver with an electrochemical method," says Magdalena Balcer, chief technologist at Nanoco and the designer of the Nano Silver technology. "As we aimed at achieving greater concentrations, we soon worked out a chemical method that delivers a concentration that is 50 times higher that those achieved with previous methods. We keep improving the technology in order to increase the product's germicidal properties. The end product is a concentrate. We dilute it in different proportions and test its effectiveness."

The preparation used at the CLO had a concentration of 200 parts per million (ppm), but in everyday life, much lower concentrations are sufficient. For example, 4-10 ppm is enough for towels, bed sheets and shirts, 20-40 ppm for socks, and 50-200 for plastic surfaces. A concentration of 1 ppm means that 1 cubic centimeter of the solution contains up to 600 trillion silver particles.

Not just medicine
Nanoco is Poland's only company that produces preparations containing such high silver concentrations, using its original technology. The company was established only two years ago and started its first research into nanosilver application on a mass scale in August 2006. Today, the company produces seven types of silver and around 30 preparations that contain it. All the technologies have been developed at Nanoco.

"The results of silver tests in the Siemianowice hospital are very promising and will certainly launch nanotechnology into the world of medicine," says Balcer. The CLO has obtained a health ministry permit for the application of Nano Silver as a biocide. Nanosilver is now being tested in several other medical facilities, as well as in the army, after a series of deaths among soldiers from septicemia, or blood poisoning.

The company wants to encourage the use of nanosilver on a mass scale in other fields as well, from the food industry, cosmetics and textile industries to construction and farming. "Our product is ecologically clean and safe for the environment; it is also quite inexpensive in comparison to rival products containing silver," said Balcer. "We have a product for the mass market-for both private consumers and corporate customers, who may want to upgrade their own products with nanosilver."

The cost of using Nano Silver in mass consumption products that gain germicidal properties in this way, is negligible. Apart from the Nano Silver biocide, which can be used to disinfect hospital surfaces, for example, Nanoco offers a wide range of products for household use, such as cleaning agents for floors, wood, tiles, glass, plastics, computer equipment, carpets and upholstered furniture. These products remove dirt and dust, providing an active anti-static and disinfecting layer. Thanks to silver nanomolecules, surfaces stay clean for longer. A fabric softener with silver nanomolecules has an anti-static effect and makes it possible to use the clothes longer as it prevents the appearance of unpleasant perspiration odors.

Bacteria, beware
Nanoco has also developed a technology for the production of germicidal polymers. This technology offers unlimited opportunities for the restaurant, food and packaging industries. Many food products have longer expiry dates if they are stored in packaging containing nanosilver. For example, lettuce stays fresh up to four weeks if wrapped in nanosilver foil, just like meat, cold cuts, and bakery and confectionery goods. In restaurants, germicidal plastic can be used for work surfaces, chopping boards, and disposable packaging and dishes.

Nanosilver opens up immense opportunities for the clothing industry. Garments impregnated or made with the use of Nano Silver fibers can prevent the development of bacteria and the resulting odors. In the summer, fabrics containing Nano Silver better reflect sunlight, reducing the feeling of heat. They also carry away heat better than traditional fabrics, which is especially useful in the case of socks, for example.

Cleaner air
Nano Silver can also significantly improve the quality of air inside apartments and offices. Fungi and mold that may cause various ailments are a frequent occurrence inside buildings. To fight that, one can use paint containing Nano Silver or impregnate the walls with it-or use wallpaper and glue with an addition of Nano Silver.

Fungi and bacteria living in air-conditioning systems in buildings and cars are particularly dangerous. When the system is turned off, microorganisms start multiplying in its filters just a few hours later. After the system is turned on, all the germs find their way into the room or the passenger cabin. The effectiveness of disinfection methods used for air-conditioning systems so far has been limited; in fact, disinfections should be carried out almost continually. Disinfection with Nano Silver ensures complete sterility that lasts from several weeks in the case of industrial filters to many months in the case of small household filters. The product's effectiveness drops as the filter fills with dust since microorganisms may live in the thick layer of dust, never coming into contact with the silver molecules.

The quality of air in a room can also be improved by using Nano Deo. The product can be used on any surface; it has a lasting refreshing effect on the air, removing unpleasant odors of all kinds-for example in smoking rooms, bathrooms, meat and fish processing plants, rooms for animals and public changing rooms, as well as inside vehicles.

Nano Silver is especially useful in public spaces such as mass transit systems, sports facilities and entertainment arenas. The product can be applied to any plastic or other surface, rendering it sterile for a long time.

Silver is golden
Nanoco has already patented its Nano Silver biocide, and keeps turning out products that contain nanosilver. It is also researching several new projects that involve ideas such as combining nanosilver with other metals and minerals to form nanocomposites with even stronger fungicidal properties. It is also in talks with several cosmetics and pharmaceutical producers to apply nanosilver in creams and other cosmetics, and in medicine packaging. An emulsion paint for interiors, containing nanosilver, is at the certification stage; it will be produced under Nanoco license.

The company has shown Nano Silver at a nanotechnology exhibition in Germany, but its main target is the U.S. market. At the moment, chemists at Nanoco, in cooperation with the CLO, are testing advanced active compresses and human skin substitutes containing nanosilver. They are also working on a non-surgical method for selectively fighting cancer cells, with the use of their original nanocomposites. The company is also working to develop heating surfaces using carbon nanotubes and is also working on methods for the production of new-generation fuels.

Ewa Dereń