Technology Review
OCTOBER 2006
NANO BIOTHYS
PORTABLE AIR
CLEANER
HEALTH TECHNOLOGY ASSESSMENT UNIT
MEDICAL DEVELOPMENT DIVISION
MINISTRY OF HEALTH
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1.
INTRODUCTION
Nanotechnology, has gained increasing importance during the last 10 years. In
particular in engineering, metallurgy, medicine and pharmacology, this area of
research opens up new perspectives in analytics and therapy.
The prefix “nano” means one-billionth. So, one nanosecond is one-billionth of a
second, and one nanometer is one-billlionth of a meter. A human hair is about
80,000 nanometers wide. The exact size is less important than the possible
applications of working with such tiny things. Nanoscience is the study and
development of the small so that it will affect the large. One of the basic goals of
nanotechnology research is to control individual atoms. Carbon, hydrogen,
oxygen and other types of atoms are the building blocks of the universe. They
make up galaxies, stars, planets, rocks, water, people, trees, CDs, cell- all the
stuff out there. If you still can’t imagine how small is a nano, pick up one tiny
grain of sand and cut it up into a billion pieces. That is how small a nano is
approximately!
Nanotechnology is an interdisciplinary field of research and is based on the
cooperative work of chemists, physicists, biologists, medical doctors and
engineer. At the interface between biotechnology and nanotechnology, nanobiotechnologists carry out research on the phenomena of self-assembly or selforganization of bio-molecules such as cell membranes or virus particles, in order
to adapt these principles to the technical production of nanostructures (Wikipedia,
2006).
Many material, once they are individually reduced below 100 nanometers, begin
displaying a set of unique characteristic based on quantum mechanical forces
that are exhibited at the level. Due to these quantum mechanical effect, material
may become more conducting, be able to transfer heat better, or modified
mechanical properties,”
Recent increasing threats of bioterrorism have aired awareness of the danger of
airborne microorganism in indoor environments. In the event of a biological
terrorist attack, large quantities of dangerous pathogenic bio-aerosol could be
released into the ventilation system of a large building endangering the lives of
thousands of civilians. The current air cleaning technology employed in some
commercial building is high efficiency particulate air (HEPA) filters. HEPA filters
are effective at trapping particles down to 0.5 microns in size; however, studies
have shown that they are not as effective at capturing airborne viruses, which
are among the smallest (20-300nm) known microorganism. HEPA filters also
have a limited lifetime and create large pressure losses within heating,
ventilation, and air conditioning (HVAC) system giving rise to higher energy costs.
Non-thermal plasma has been proven to inactivate many different types of
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microorganisms, such as viruses and bacteria, on surface of materials, but there
have been few scientific studies of air sterilization using non-thermal plasma
(Wikipedia, 2006).
2.
TECHNICAL FEATURES
The Nano Biothys portable air cleaner uses the latest nano technology developed
by Korean engineers to kill bacteria and viruses for air purification. The air
cleaner has an efficiency of Clean Air Delivery Rate (CADR) of 450 CADR (the
highest CADR portable air cleaner recorded compare to other brands). Figure 1
shows a schematic main components of the air cleaner. It consists of external
parts of Aroma materials case, Anion Outlet, Outlet of Clean Air, Main Controller
and Indicator, Inlet of Polluted air and a power supply plug. The internal
components includes the upper grill, Microdust filter (4EA), Electrostatic filter
(2EA), Prefilter (4EA), Multifunctional deodorization filter (2EA), Suction Prefilter
(2EA) and left, right grill. (see Figure 2) The system is capable to dissipate at air
flow rates up to 388 cubic ft per minute (Zalmandn, 2005)
Figure 1 : Nano Biothys air
cleaner -
External
components
The multifunctional deodorization filter was installed by performing a special
chemical treatment to granular activated carbon, crush carbon fibers and powder
activated carbon in polyurethane forms. It has a strong pollutant holding
performance and a highly effective deodorization filters by a new manufacturing
process are superior in their purifying performance of stench and harmful
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substances. The prefilter was used to remove large size dusts in the air entering
from the environment. Medium filter can precipitate up to 95% of dusts with the
size of 0.4 um. The HEPA filter which can precipitate up to 99.97 % of minute
dust of 0.3 um. Ulpa filter is a filter which can precipitate up to 99.9997 % dusts
with the size of 0.12 um. The Chemical filter can effectively remove Ammonia
(NH3), Sulphur (S), Nitrogen (N), Sulfhydryl (RSH) as a effect of depository of
toxic gas.
components
Figure 2 : Nano Biothys air cleaner Internal
3. OBJECTIVE
To determine the effectiveness and safety of Nano Biothys Portable Air Cleaner.
4. METHODOLOGY
Retrieval of evidence – An electronic search using the following search engines
and data bases were carried out :- Yahoo, Googgle, PubMed, Ebsco, Cinahl,
Embase and Cochrane.
The following keywords were used in carrying out the search which includes :
Nano technology, Nano Biothys air sterilizer, Nano-Silver and Copper porous filter,
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Analysis of evidence – Interpretation and conclusion of diagnostic laboratory in
vitro testing and other supportive clinical or industrial findings was directly
contributed by the company.
5. RESULTS AND DISCUSSION
In 1971 The Silver Institute began to report worldwide development for the use
of silver in its publication, New Silver Technology, and encourage the
development of silver system to purify water, air and control bacteria. It has long
been known that oxygen is adsorbed on the surface of silver in its atomic state.
Also that oxygen diffuses more freely within silver than within any other metal
(Chaston, 1967). Ronald Outlaw, working at NASA/Langley, undertook a
fundamental study of oxygen diffusion with the objective of producing atomic
oxygen for the evaluation of the degradation of organic materials in space. He
discovered the most prolific source of nascent oxygen to be metallic silver.
Atomic oxygen fits very well in the octahedral holds of gold, silver and copper. In
gold, the electron cloud of oxygen tends to be repelled by the lattice electrons of
the gold atoms stooping movement through the holes. With cooper, the oxide is
formed resulting in a barrier. Silver, with an utmost a perfect fit, offers so little
repulsion that a little thermal energy will readily move it from hole to hole
(Eberhart, 1992).
In 1986 a patent covering the aqueous, catalytic action of silver for the oxidation
of bacteria, was issued to Charles Heinig , assigned to Fountainhead
Technologies, Providence, RI, USA. The fluid to be treated passes through a bed
with a large surface
area of metallic silver, on a benign substrate. Molecular oxygen is present and
silver readily adsorbs it converting it to nascent oxygen which is available to
oxidize bacterial enzymes and other organics (Heinig, 1986).
Silver has been used for the treatment of medical ailments for over 100 years
due to its natural antibacterial and antifungal properties. Nanopac nanosilver
particles typically measures 5-50 nm. They have extremely large relative surface
area, increasing their contact with bacteria, virus or fungi, and vastly improving
its bactericidal, virucidal and fungicidal effects (McGrath, 2006).
The nanosilver when in contact with bacteria, virus and fungus will adversely
affect cellular metabolism and inhibit cell growth. The nanosilver inhibits
multiplication and growth of bacteria and fungi which cause infection, odour,
itchiness and sores (McGrath, 2006).
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5.1
Effectiveness
The consumer may be confronted with a variety of manufacturers’ claims about
the performance and “efficiency” of various units. A good performance on an
efficiency test that measures the capture of large particles does not mean that
small particles will be controlled. Some of this information may mislead the
consumer seeking the control of fine particulates.
The effectiveness of this air cleaner found to be effective in combating microbes
and viruses for air pollutants. Clean Air Delivery Rate (CADR) is the amount of
filtered air that is free from three major pollutants viz. dust, pollen and cigarette
smoke. Higher number indicates higher rate of filtration and thus an efficient
filter. Ideally, it is rational to install an air cleaner which have a rate of CADR
around two third of the area of the room whose air we want to filter.
Three mechanisms of silver sanitation are reported in the literature: catalytic
oxidation of cell surface radicals to inhibit transfer of oxygen, reaction with
surface radicals on the surface of bacteria and viruses to interfere with electron
transport, and binding with DNA in disease organisms to prevent unwinding
(McManus, 1995).
Catalytic Oxidation – Atomic (nascent) oxygen adsorbed onto a bed of silver
atom or ion in solution readily reacts with the sulfhydryl (H) groups surrounding
the surface of bacteria or viruses to remove the hydrogen atoms (remove as
water) causing the sulfur atoms to form an R-S-S-R bond; respiration is blocked
and the bacteria expire.
Albert T. McManus, MD, Chief of Microbiology, Institute of Surgical Research,
Fort Sam Houston Army Burn Center, Houston, Texas, observe, “Silver kills
bacteria by simple catalytic reduction/oxidation by reacting with any available
negative charge. There are all kinds of transport proteins and membrane protein
that have charge on them. For pure protein enzymology, silver is a very potent
inhibitor; the reaction it catalyses inactivate the protein. When it binds to nucleic
acid, it is simple oxidation at a phosphate radical. Silver will bond any organic
acid that ionized. Any organism that is available to powerful catalytic activity of
silver for oxidation is inactivated” (McManus, 1995).
Studies by Charles Heinig showed that lightly bound nascent oxygen on the
microcrystals of silver (about 40 kilocalories per mole) readily oxidizes bacteria or
viruses, resulting in complete disintegration. It also oxidizes other organic and
inorganic materials, forming relatively stable peroxides that continue to sanitize
the water downstream. His experiments with ozone gas additions showed that
bacteria and viruses were being tom apart, the silver acting purely as an
extremely efficient oxidative catalyst (Heinig, 1986).
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Reaction with Bacterial Cell Membrane- There is evidence that silver ions
may attach to surface radical of bacteria, impairing cell respiration by blocking its
energy transfer system. An unpublished study of bacteria treated with radiated
silver showed that silver was present on the surface, but did not penetrate the
cell. It should be noted that mammalian cells are not affected by silver because
the protective cell walls block entry of large ions such as silver
The research at Colombia University, Department of Microbiology, continuing
under Shanta Modak, is studying the development of a new family of quinolone
silver compounds. These, when mixed with silver sulfadiazine, are expected to
inhibit the generation of resistant bacteria (Modak, 1988).
Viruses – There is no comprehensive study of viruses inactivated by silver.
However, the Journal of Nanotechnology has published a study that found silver
nanoparticles kills HIV-1 and is likely to kill virtually any other virus. The study,
which was conducted by the University of Texas and Mexico University, is the
first medical study to ever explore the benefits of silver nanoparticles. Viruses are
basically pure DNA or RNA with a protein like coating and no cell membrane.
Because many have sulfhydryl terminuses, their reaction to silver would be
similar to that of bacteria. In one study, Fox showed that silver sulfadiazine
causes direct inactivation of herpes simplex and vesicular stomatitis, viruses that
affect the eyes (Tokumaru, 1984).
Silver sulfadiazine, unlike silver nitrate, is active against both gram positive and
gram negative organisms, fungi and protozoa, including mouse infected by
malaria. It also topically effective against viruses such as herpes and sexually
transmitted diseases such as genital herpes, gonorrhea, Trichomonas and
Treponema pallidia. It also inhibits the colony formation of Staphylococcus,
Streptococcus, Pseudomonas, etc.
Binding with DNA- Studies by Fox of Pseudomonas with sublethal concentrations
of silver sulfadiazine revealed that up to 12% of the silver was in the DNA
fraction, 3% of silver was in the RNA fraction, less than 0.5% in the lipid fraction
and the remainder in its protein and polysaccharides (Modak, 1973). F.A.Cotton
examined possible ways in which the large silver atom might fit into DNA, but
believed that a N-N bonding with a separation of ca. 3.8 A would increase the
nearby N-H…0 separations and abolish the hydrogen bonds on which the DNA
structure depends (Cotton, 1994). More research is
required. When silver does bond with DNA, the resulting complex is not unwound.
However, in treating the complex with chlorides, bromides, cyanides, etc, which
remove the silver, regeneration of the native DNA takes place and its function is
restored.
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Silver is capable of destroying singled-celled bacteria, viruses and fungus by
disrupting the cell’s breathing mechanism (it inhibits the metabolism of oxygen).
This action annihilates the organism’s cell membranes and halts DNA replication.
Killing pathogens is only one of silver’s remarkable qualities (McGrath, 2006).
5.2 Safety
The Korean made air sterilizer employs one of the most advanced sterilization
technologies in the Nano Biothys portable air sterilizer. The air sterilizer use prefilter which was applied with porous nanosilver and copper. The porous silver
and copper filter is said to be effective in killing the microbes from growing inside
the unit and prevents allergy-causing bacteria and virus from being blown in the
air. Nanosilver and copper porous filter reduce the presence of bacteria and virus
within 30 to 40 minutes of operation (Zalmandn, 2005).
The usage of the portable air sterilizer are environment friendly and non toxic.
The system are harmless to human body since there was no generation of ions
and ozone gases. It has many multi-functions such as anti-bacteria, anti-virus,
sterilization and deodorization. The portable air sterilizer can kills a broad range
of anti-bacterium and have an excellent cleaning capability by trapping large size
particles and dust (Zalmandn, 2005).
6. CONCLUSION
There is moderately sufficient evidence to support the efficacy of Nano Biothys
portable air sterilizer from independent research reports which clearly prove the
unit’s efficacy in eradication of organisms, delivering air circulation and to
provide total confidence in its ability to “Engineer Air Sterility” for medical
industry (Zhang 2004, Hahnas 2005 and Shannon 2006). Using porous silver air
filter are much superior than the copper filter since silver is known that to
adsorbed oxygen on the surface of its atomic state. It is also known that oxygen
diffuses more freely within silver than within any other metal. Although the
portable air cleaner has being distributed widely to the end user, no known
clinical trials has been carried out. Thus more clinical studies is warranted in the
near future.
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