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hen serious illness or

infection strikes, we turn to our doctors and hospitals for

treatment and recovery. But because they concentrate so many

germs in one place, hospitals are themselves a leading source of

infection. In fact, over one hundred thousand hospital patients

die every year from infections contracted in American hospitals.

Many of the bacteria that cause these infections are spread

through contact with surfaces, including doors and hardware.

To combat the spread of infectious bacteria and other harmful

microbes, Americans spend over $1 billion each year on

antimicrobial products. While ordinary disinfectants can be

effective at killing harmful bacteria, they typically do not last

long, wearing or washing off of surfaces after they are applied.

But could a new technology offer a new line of defense in

protecting doors and hardware from carrying germs?

Nanotechnology, the manipulation of matter at the molecular scale,

may hold the answer. Nanotechnology works at the scale of one

billionth of a meter, where chemical and mechanical properties

are governed as much by the peculiar rules of quantum physics as

by the Newtonian principles that affect bulk materials at a larger

scale. Nanoscientists are finding it possible to change material

properties like color, liquid/solid/gas state, porosity and conductivity

quite easily by working with particles at the nanometer scale.

NaNotechNology

by Dr. GeorGe elvin

Fighting Germs on the Frontline

W

FEBRUARY 2008 £DOORS&HARDWARE 15

What this means for the fight against infectious disease is a new breed of antimicrobial coatings, or nanocoatings, with dramatic germ-killing abilities, improved durability, and reduced environ-mental toxicity. By specifying surfaces and surface treatments that integrate antimicrobial nanoparticles like titanium dioxide and silver dioxide, architects and interior designers are reducing the

spread of infectious diseases in hospitals and other public venues.

The London tube and Hong Kong subway are good examples of large-scale public projects adopting nanocoatings in the fight against disease. Many surfaces that people touch every day in a subway carry thousands of bacteria and germs. With news of power-ful flu strains like avian flu and hand-transmissible diseases like colds, public transportation opera-

tors are using new nano-enhanced disinfectants in their subways.

“Public transportation is a very common way, we know, of how diseases… spread,” said Ben Mascall, spokesman with MTR Corp., which operates the railway in Hong Kong and has bid for two new rail franchises in the U.K.

Mascall’s company has coated its cars’ interiors with titanium and silver dioxide nanocoatings that kill

most of the airborne bacteria and viruses that come into contact with them. The London tube will soon do the same. Preliminary tests show the disinfectant has reduced the presence of bacteria in coated Hong Kong subway cars by 60 percent.1

HospitalApplications

In hospitals, all kinds of surfaces are being coated with these materi-als to reduce the spread of germs.

There’s even a nano-necktie made from the same stuff that’s marketed to doctors, and it’s 99.99 percent effective in reducing the spread of infectious bacteria.

Many paints contain nanopar-ticles to prevent mildew, including Zinsser’s Perma-White Interior Paint, Behr Premium Plus Kitchen & Bath Paint, and Lowe’s Valspar. Researchers at the Fraunhofer Institute for Manufacturing

Engineering and Applied Materials Research IFAM in Bremen and at Bioni CS have developed a process for binding antibacterial silver nanoparti-cles permanently to paint. According to Bioni, the coating is certified as emission-free, and can destroy antibiotic-resistant bacteria. They report that their coating has been used in more than 20 hospital proj-ects in Europe and the Gulf region, including the 40,000 square meter Discovery Gardens project in Dubai.

BASFengineersexamineanHerbol-SymbiotecpaintsamplebasedonBASF’snanobinderCOL.9,whichreducesgermtransmissionanddirtpick-up.(Source:BASF)

Nano-products

may cause

unanticipated

environmental

risks.

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Antimicrobial nanocoatings can also be incorporated into ceramic surfaces. The German plumbing-fixture manufacturer, Duravit, for example, has teamed with Nanogate Technologies to develop a product called Wondergliss. Wondergliss coating is fired over traditional ceramic glazing to create a surface so smooth that dirt, germs, and fungus cannot stick to it. In addition, water beads up and runs off the hydrophobic surface without lime and soaps being able to build up.2

Microban International offers Microban, which they call the first antimicrobial polymeric, a plastic resistant to germs, molds, yeast, and mildew. Microban is used in more than 450 products ranging from cleaning supplies, paints and caulking to medical products, plumbing fixtures, and other kitchen and bath products. Their product, they say, does not wash or wear off of its material substrate.

BioQuest Technologies is market-ing itsBioShield 75, a nanotech- and

water-based antimicrobial with no poisons, as a preventative product for use in homes and businesses in hurricane paths. Proactive applica-tion, they suggest, will reduce bacteria and provide an effective solution to microbial problems that continue to exist in homes and busi-nesses after hurricane damage.3

While antimicrobial nanocoat-ings are not yet incorporated into door hardware, several products employ nanotechnology to reduce germs transferred by contact with doorknobs and handles. One, called “The Handler,” is a handheld device that deploys a zinc alloy hook designed to grip a door handle. It is made with silver dioxide nanoparticles that its manufacturer say instantly kill the most common types of germs that can cause illnesses and infec-tions. Tests show that these silver particles are highly effective in killing microorganisms ranging from harmful strains of e. coli that cause food-borne diseases to the staphylococcus bacteria responsible for serious infections. Laboratory tests show that the handler kills 98 percent of methicillin resistant Staphylococcus aureus on contact and 99 percent after two minutes.4

Another device, the Handheld Germ-Eliminating Light, uses UV-C light and nanotechnology in a cell phone-sized disinfectant light to elim-inate 99.99 percent of E-Coli, staphy-lococcus, salmonella, and germs that cause the flu and the common cold. The light uses the same UV technol-ogy found in hospitals to sterilize surgical instruments, allowing users to disinfect workplace keyboards or telephones, as well as items in the home that sustain germ vitality such as toothbrushes and cutting boards.5

Anantimicrobialcoatingofsilverdioxidenanoparticlesonthe“Handler”helpsusersavoidgermswhenopeningdoors.(Source:MakerEnterprisesLLC)

FREEADVERTISERINFORMATIONAT:www.thru.to/dhi

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Today’s antimicrobial nano-products are just the tip of the iceberg, with many more to come as university and research center projects evolve into useful products. Researchers at Yale University, for instance, have found that carbon nanotubes can kill E. coli bacteria. In their experiments, roughly 80 percent of these bacteria were killed after one hour of exposure. The researchers said nanotubes could be incorporated during the manufac-turing process or applied to existing surfaces to keep them microbe-free.

MultifunctionalCoatings

Many nanocoatings can do more than just kill germs. Bioni, for example, offers nanocoatings with

a combination of antimicrobial and heat deflective properties. Their low thermal conductivity and the ability to reflect up to 90 percent of the sun’s rays reduce heat absorption in coated walls, thereby reducing air condition-ing and energy consumption.6

Nansulate LDX from Industrial Nanotech is designed to encapsulate lead-painted surfaces, making them inaccessible by providing an overcoat barrier. At the same time, it provides mold resistance, thermal insulation, and protection against corrosion. Three out of four homes built prior to 1978 contain lead-

based paint, and according to the EPA, residential lead abatement has cost $570 billion and commercial $500 billion. In the past fifteen years, encapsulation as an abatement tech-nique has become a cost-effective alternative solution, typically cost-ing 50 to 80 percent less than lead paint removal and replacement.7

Environmentaleffects

The Yale University researchers who found that carbon nano-tubes can kill E. coli bacteria also recognized that since nanotubes can kill bacteria, they could have a major impact on ecosystems. “Microbial function is critical in ecosystem sustainability and we rely on microbes to detoxify wastes in environmental systems,” said Joseph Hughes of Georgia Tech. “If they are impaired by nanotubes, or other materials,” he concluded, “it is the cause for significant concern.”8The U.S. Environmental Protection Agency (EPA) now regulates nano-products sold as germ-kill-ing, believing they may pose unanticipated environmental risks.

Conventional antimicrobial prod-ucts are marketed in sprays, liquids, concentrated powders, and gases. The EPA says that conventional antimicrobial products can contain any of about 275 different active ingredients, including biocides, which may release into the environ-ment. Some biocidal ingredients in antimicrobial products pose both environmental hazards and indoor air quality concerns. Antimicrobial nanocoatings reportedly offer the benefits of conventional antimi-crobial products without these environmental and health concerns.

With all of these benefits, what’s keeping architects and interior

designers from coating every-thing in sight with antimicrobial nanoparticles? For one thing, consumers are still largely reliant on manufacturer claims as to perfor-mance. Cost is another hurdle, as nanocoatings typically cost more up front than their conventional counterparts. However, if they prove more effective at fighting infectious diseases and last longer, we can expect to see more antimi-crobial nanocoatings for doors and hardware in coming years.

About the Author: Dr. George Elvin is the director of Green Technology Forum (green-techforum.net), a leading design, research and advising firm focusing on emerging green technologies for sustainable business and green building. He is also an associate professor at Ball State University, and his books and articles have been published by Wiley, Princeton Architectural Press, and the American Society of Civil Engineers. He is a former Visiting Fellow at the University of Edinburgh’s Institute for Advanced Studies in the Humanities and the Center for Energy Research, Education and Service. Dr. Elvin can be contacted at elvin@greentechforum.net. The full report, “Nanotechnology for Building Security,” which contains more information on antimicrobial nanocoatings and related nanotechnologies for building, can be purchased at greentechforum.net/security.

Footnotes:1. Barnier, Benjamin, “London Might Disinfect Its Underground,”

ABC News, Oc t . 23, 20 0 6, ht t p://abc news.go.com/International/print?id=2600360

2. Duravit, “Wondergliss”, http://www.qkb.com/duravitwon-dergliss.htm

3. BioQuest Technologies, “Bioshield 75: Biostatic Surface Protectant,” http://www.bioquestech.com/bioshield75.shtml

4. The Handler, http://www.handlerusa.com/home.php, 20065. Elvin, George, “Handheld Light Claims to Eliminate Germs,”

nanotechbuzz.com, December 31, 2006, http://www.nano-techbuzz.com/50226711/handheld_nano_light_claims_to_eliminate_germs.php

6. TCM Asia Bioni Technology, “BIONIC nanotechnology bionic functional coatings,” 2005, http://www.tcm-asia.com/bioni_e.html

7. Industrial Nanotech, Inc., “Industrial Nanotech, Inc. to Enter Global Lead Abatement Market with Launch of New Product: Nansulate LDX,” press release, April 26, 2006, http://www.primenewswire.com/newsroom/news.html?d=97988

8. Inman, Mason, “Bug-popping nanotubes promise clean surfaces,” NewScientist.com, 22 August 2007, http://tech-nology.newscientist.com/article/dn12521-bugpopping-nanotubes-promise-clean-surfaces.html

Hospitals are a leading source of infection.