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Though the photocatalytic properties of Titanium Dioxide has been known for many years, it wasn't until NASA helped develop it for use on the International Space Station as an air purification system that it became somewhat viable.  Pure-Light Technologies has taken the NASA technology and improved upon it in several ways to share its benefits with the world.  
 

THE SCIENCE 

What Makes Pure-Light So Unique?

The unique action of a PURE-LIGHT TECHNOLOGIES light bulb is that it uses light in a photocatalytic action to continuously create two special types of super oxygen molecules called Superoxide (0-2) and Hydroxyl ion radical (HO) that breakdown bacteria, viruses, mold, and also breakdown toxic VOC pollutants. The air that we breathe is full of these bacteria, viruses, mold, toxic pollutants (called VOC--Volatile Organic Compounds like Carbon Monoxide, Benzine, Formaldahyde...)  especially in enclosed areas like hospitals, schools, businesses, and homes looking for a place to land and grow.  As air comes near a light bulb coated in our Pure-Light formula, it gets cleansed of these bacteria, viruses, mold, and pollutants. The air also gets deoderized as well.  There is also a secondary PURE-LIGHT effect on the surfaces of items near the light bulb, such as kitchen/bathroom counters, dishes, stoves, cutting boards, door knobs, etc.

• The unique photocatalytic phenomenon or action was discovered in 1967.

• The well known PHOTOCATALYTIC ACTION of TiO2 is such that when light hits it, it produces a special type of excited electron. This excited electron, when it comes into contact with a water molecule, changes the water molecule (H20) into a couple of types of special super oxygen molecules called    SUPEROXIDE (O-2) and HYDROXYL ION (HO). These two super oxygen molecules provide a triple "action"... two actions against viruses and bacterias, and another "action" against VOCs.
SUPEROXIDE (O-2), or super oxygen (also called hyperoxide), is actually produced in the human body in large quantities by Phagocytes (White blood cells)  and is used by the immune system to kill invading microorganisms.

Superoxide (O-2) inside the body, or in the air, combines with a microorganism giving it essentially a boost of oxygen. Good cells thrive with the extra oxygen while viruses and bacteria are killed by the extra oxygen.

Superoxides are also used in firefighterers' oxygen tanks and divers rebreather systems in order to provide a readily available source of oxygen.

The HYDROXYL ION radical (HO) is often referred to as the "detergent" of the atmosphere because it reacts with many pollutants called VOCs (Volatile Organic Compounds), often acting as the first step to their removal.

Hydroxyl radicals also attack the porous cell walls of bacteria and viruses which destroys them through the process known as cell lysing. Human, animal and plant cells are “designed” to be in the sunlight and have cell walls that are less porous and are not harmed by atmospheric hydroxyl radicals.

WHAT MAKES PURE-LIGHT BULBS UNIQUE?

Though the properties of TiO2 are well documented, there have been problems in the past with applications:

* The first problem is that the photocatalytic process of TiO2 works well with sunlight or high power UV lights but not with ordinary light. PURE-LIGHT overcomes this by using a newly developed proprietary enhanced TiO2 formulation (Z-TiO2) that works extremely well with ordinary light. PURE-LIGHT TECHNOLOGIES has the exclusive rights to use this new formulation on light bulbs.

* The second problem is getting the TiO2 to "stick" to a surface longer than a few weeks or months. That is why other companies have tried to do it, but it has not worked very well for them. PURE-LIGHT has developed a new patent pending process that can "seal" the TiO2 to the surface of a light for up to 10 years. Since PURE-LIGHT developed it, no one else has it.


PURE-LIGHT TECHNOLOGIES LAB STUDIES

  
 1.  Pure-Light Study #1: Barley Sprouts and mold  November 2017

Conducted by: Sustainable Lighting Solutions Christopher Rakowitz & Ken Chio

The purpose of this experiment was to determine the effectiveness of the Pure Light coating using photocatalytic activation specifically to control mold and yeast on barley sprouts.

Conclusion:  Pure-Light not only dramatically reduced the heavily introduced mold, but doubled the growth of the Barley sprouts. 

"The photocatalytic technique appears to be a versatile and efficient disinfection process capable of inactivating a wide range of harmful microorganisms in various media. It is a safe, nontoxic, and relatively inexpensive disinfection method whose adaptability allows it to be used for many purposes. Mold levels are very significantly reduced under very difficult conditions not normally seen in horticulture. Typical conditions would not promote mold before and during a cultivation period and therefore would never reach levels of mold found in our testing. Under normal conditions, it would be expected from our test results that mold levels would very easily be controlled by use of the Pure-Light coating."


2. Pure Light Study #2: Pure-Light Bulbs (only) Effectiveness against E-Coli, Salmonella, and MRSA. February 2018. 

"Glass slide and laminated wood flooring coupons were inoculated in triplicate with a suspension of Escherichia coli, Salmonella enterica, and methicillin-resistant Staphylococcus aureus (MRSA). The slides and wood flooring samples were exposed to PURE-LIGHT coated LED light bulbs and tested at 24 and 72 hour intervals to determine organism survival/reduction. Control slides and coupons (not exposed to light bulbs) were also tested at 24 hour and 72 hour intervals for comparison purposes. The glass slide coupons were set on a counter approximately 5 feet from the surface of the lights. The wood flooring coupons were set on the floor of the room approximately 8 feet from the lights."

"CONCLUSIONS/OBSERVATIONS:
"The greatest bacterial reduction was seen after 72 hours of treatment compared to 24 hours. E. coli was reduced by 94.7% on glass and 93.3% on the wood surface after 72 hours of treatment. MRSA was reduced by 80.6% and 80.0% on glass and wood after 72 hours. S. enterica was also reduced but by a smaller degree; 47.3% on glass and 57.4% on wood after 72 hours of treatment."

....click here for full study in pdf format... ​

3.  Pure-Light Study #3: Pure-Light Bulbs + Pure-Light Sani-Light Coating against Salmonella, E-Coli, MRSA

EXPERIMENTAL SUMMARY
Glass slides coated with PURE-LIGHT SANI-LIGHT® solution were inoculated in triplicate with a suspension of Escherichia coli, Salmonella enterica, and Methicillin-resistant Staphylococcus Aureus. One group of slides was exposed to PURE-LIGHT coated LED light bulbs at counter and floor levels and another group was not exposed to the light also at counter and floor levels. All slides were tested after 24 hours to determine organism survival.

CONCLUSIONS/OBSERVATIONS 
Bacterial reduction of Salmonella and MRSA inoculated onto the surfaces of PURE-LIGHT SANI-LIGHT® coated slides ranged from 97 to 99.9% when compared to the same organisms inoculated at the same levels onto uncoated slides and exposed to the same conditions. The greatest reduction was observed in the organism average of the slide group exposed to the PURE-LIGHT LED light bulbs at counter height (about 5 feet below light bulbs) while the least reduction was observed in the organism average of the slide group not exposed to the PURE-LIGHT LED light bulbs at Floor level. Reduction of E. coli could not be accurately determined as the recovery of the uncoated control slides at 24 hours was below detection limits. It appears the survivability of E. coli  after 24 hours was very low regardless of the slide type the organism was inoculated on.


Click here for the full study

4. There are currently additional studies in the process of being conducted with the Pure-Light Coated Bulbs and the Pure-Light Sani-Light™ Counter Coating. 

​Hepatitis A

Influenza A (H5N1 Flu)

Plague

MRSA

Salmonella

E-Coli

Necrotizing Fasciitis (flesh eating disease)

Haemorrhagic Fever  (Ebola)

Tuberculosis   
  
Cholera    

Below are a number of studies that delve into the properties and uses of titanium dioxide nanoparticles.

Compared to Chlorine disinfection, Ozonation, irradiation using germicidal lamps which all have problems, the 
TiO2 photocatalytic process is Nontoxic, chemically stable, safe, nonhaxardous and ecofriendly.
Applications of Photocatalytic Disinfection - Hindawi

www.hindawi.com/journals/ijp/2010/764870

Applications of photocatalytic processes are widely recognized as viable solutions to environmental problems [13]. Disinfection of bacteria is of particular importance, because traditional methods such as chlorination are chemical intensive and have many associated disadvantages. For example, in water treatment applications, chlorine used for disinfection can react with organic material to generate chloro-organic compounds that are highly carcinogenic [45]. Furthermore, some pathogens such as viruses, certain bacteria such as Legionella, and protozoans such as Cryptosporidium and Giardia lamblia cysts have been known to be resistant to chlorine disinfection [67]. Other treatment alternatives such as ozonation and irradiation using germicidal lamps (254 nm) have their own problems and limitations, such as the lack of residual effect [8] and generation of small colony variants [9] for the latter and production of toxic disinfection byproducts for the former [10].

In comparison, the  semiconductor commonly used in photocatalytic processes is nontoxic, chemically stable, available at a reasonable cost, and capable of repeated use without substantial loss of catalytic ability [11]. Heterogeneous photocatalysis using titanium dioxide is a safe, nonhazardous, and ecofriendly process which does not produce any harmful byproducts. Extensive research in this field has been done in the area of photocatalytic removal of organic, inorganic, and microbial pollutants [1213].


International Journal of Photoenergy Volume 2010 (2010), Article ID 764870, 11 pages
Abstract:
Due to the superior ability of photocatalysis to inactivate a wide range of harmful microorganisms, it is being examined as a viable alternative to traditional disinfection methods such as chlorination, which can produce harmful byproducts. Photocatalysis is a versatile and effective process that can be adapted for use in many applications for disinfection in both air and water matrices. Additionally, photocatalytic surfaces are being developed and tested for use in the context of “self-disinfecting” materials. Studies on the photocatalytic technique for disinfection demonstrate this process to have potential for widespread applications in indoor air and environmental health, biological, and medical applications, laboratory and hospital applications, pharmaceutical and food industry, plant protection applications, wastewater and effluents treatment, and drinking water disinfection. Studies on photocatalytic disinfection using a variety of techniques and test organisms are reviewed, with an emphasis on the end-use application of developed technologies and methods.


Develop Methods To Assess And Improve Poultry And Egg Quality


Interpretive Summary: Salmonella and Listeria are commonly detected in both raw and ready-to-eat meat products, and are responsible for many outbreaks of foodborne diseases in the USA. Nano-TiO2 has been demonstrate to be very effective to inhibit microbial growth under UV light, and is considered as a novel material that can be used for eliminating microbial pathogens from food. The objective of this study was to investigate the antimicrobial effects of nano-TiO2 particles on bacterial pathogens, Salmonella typhimurium and Listeria Monocytogenes, which are commonly found on raw and/or cooked poultry meat products. Our results show that nano-TiO2 effectively reduced the populations of either of the pathogens under UV light. Its effectiveness could be affected by nano-TiO2 concentrations and the initial microbial populations. L. monocytogenes was more resistant to nano-TiO2 treatment than Salmonella. Electronic microscopic images showed that under UV light, nano-TiO2 resulted in damage of bacterial cell walls, release of cell components, and subsequently the cell death. These results demonstrate that we can use nano-TiO2 to treat food products and reduce the risk of foodborne diseases by reducing pathogen populations and/or inhibiting pathogen growth.


Studies of photokilling of bacteria using titanium dioxide nanoparticles

Abstract
Metal pins used to apply skeletal traction or external fixation devices protruding through skin are susceptible to the increased incidence of pin site infection. In this work, we tried to establish the photokilling effects of titanium dioxide (TiO2) nanoparticles on an orthopedic implant with an in vitro study. In these photocatalytic experiments, aqueous TiO2 was added to the tested microorganism. The time effect of TiO2 photoactivation was evaluated, and the loss of viability of five different bacteria suspensions (Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Enterococcus hirae, and Bacteroides fragilis) was examined by the viable count procedure. The bactericidal effect of TiO2 nanoparticle-coated metal plates was also tested. The ultraviolet (UV) dosage used in this experiment did not affect the viability of bacteria, and all bacteria survived well in the absence of TiO2 nanoparticles. The survival curve of microorganisms in the presence of TiO2 nanoparticles showed that nearly complete killing was achieved after 50 min of UV illumination. The formation of bacterial colonies above the TiO2 nanoparticle-coated metal plates also decreased significantly. In this study, we clearly demonstrated the bactericidal effects of titanium dioxide nanoparticles. In the presence of UV light, the titanium dioxide nanoparticles can be applicable to medical facilities where the potential for infection should be controlled.


Technology For Growing Plants In Space Leads To Device That Destroys Pathogens, Like Anthrax

Building miniature greenhouses for experiments on the International Space Station has led to the invention of a device that annihilates anthrax -- a bacteria that can be deadly when inhaled.
"Space-based greenhouses may seem to have little to do with the war against terrorism," said Mark Nall, director of the Space Product Development Program at NASA's Marshall Space Flight Center in Huntsville, Ala. "Yet this invention shows how commercial space research can benefit people on Earth in unexpected ways."
The anthrax-killing air scrubber, AiroCide Ti02, is a tabletop-size metal box that bolts to office ceilings or walls. Its fans draw in airborne spores and airflow forces them through a maze of tubes. Inside, hydroxyl radicals (OH-) attack and kill pathogens. Most remaining spores are destroyed by high-energy ultraviolet photons.
"Spores that pass through the box aren't filtered -- they're fried," said John Hayman, president of KES Science & Technology Inc., the Kennesaw, Ga.-company that manufactures AiroCide Ti02. "That's appealing because you don't have to change an anthrax-laden air filter."
The technology to build the anthrax killer emerged from another product, Bio-KES, which is used by grocers and florists to remove ethylene and thus extend the life of vegetables, fruits and flowers. Ethylene (C2H4) is a gas released by the leaves of growing plants -- but too much of it can build up in an enclosed plant growth chamber or produce storage facility.
Too much ethylene causes plants to mature too quickly, fruit to ripen prematurely, and it even accelerates decay. This hinders researchers' efforts to harvest healthy plants grown in space and would also be undesirable when space travelers build larger space-based greenhouses for growing fresh food.
The research that led to the invention of Bio-KES started with a crucial discovery made in the early 90's by scientists at the Wisconsin Center for Space Automation and Robotics - a NASA Commercial Space Center at the University of Wisconsin-Madison. These scientists collaborated on the discovery with Dr. Marc Anderson, a professor and chemist who also works at the university.
The research team found that ultra-thin layers of titanium dioxide (TiO2) exposed to ultraviolet light converted ethylene into carbon dioxide (CO2) and water (H2O) -- substances that are good for plants. Subsequently, they developed a coating technology that applies TiO2 layers to the surfaces of many materials.


UCL scientists develop novel approaches for killing MRSA and E.coli
Dr Sean Nair, Michael Wilson
New research from the UCL Eastman Dental Institute and UCL Chemistry, presented at the spring conference of the Society for General Microbiology (SGM), has provided a potential drug for MRSA treatment and a new antibacterial coating using Titanium Dioxide which will help fight hospital-acquired infections.
Research from the UCL Eastman Dental Institute has resulted in the development of a light-activated drug that could be used in the treatment of infections caused by the hospital bug MRSA.  Researchers attached an antimicrobial drug, which is activated by light, to a peptide (a protein fragment) that binds onto a molecule on the surface of the superbug bacteria. Such light-activated antimicrobial agents produce free radicals and an unstable form of oxygen when they are exposed to light at the right wavelength. The release of these free radicals damages and ultimately kills bacteria.   99.97% of 10 million MRSA cells were killed using this new combination, which was 1,000 times more effective at killing MRSA compared to the commercially available SnCe6 when the same quantity is used. 


UCL scientists develop Light-activated antibacterial coating against hospital-acquired infections

Ivan Parkin, Dr Charles Dunnill, Michael Wilson, Dr Jonathan Pratten, and Zoie  Aiken from the UCL Eastman Dental Institute have  developed a hard coating with antibacterial properties that has been shown to kill 99.9% of 10 million Escherichia coli (E.coli) bacteria when a white hospital light was shone on its surface.  The veneer-like surface is made of titanium dioxide with added nitrogen. When it is activated by white light, similar to those used in hospital wards and operating theatres, it produces a decrease in the number of bacteria surviving on the test surface.  The hospital environment acts as a reservoir for the microbes responsible for healthcare-associated infections (HCAI) and new ways of preventing the spread of these pathogens to patients are needed. Antibacterial coatings could be applied to frequently touched hospital surfaces to kill any bacteria present and help reduce the number of HCAI. Titanium dioxide based coatings are known to kill bacteria after activation with UV light. The addition of nitrogen to these coatings enables photons (the basic unit of light) available in visible light to be utilised to activate the surface and kill bacteria.
 


Bactericidal activity of photocatalytic TiO2 reaction: toward an understanding of its killing mechanism

PC Maness, S Smolinski, DM Blake… - Applied and …, 1999 - Am Soc Microbiol
When titanium dioxide (TiO2) is irradiated with near-UV light, this semiconductor exhibits strong bactericidal activity. In this paper, we present the first evidence that the lipid peroxidation reaction is the underlying mechanism of death of Escherichia coli K-12 cells that are irradiated in the presence of the TiO2 photocatalyst. Using production of malondialdehyde (MDA) as an index to assess cell membrane damage by lipid peroxidation, we observed that there was an exponential increase in the production of MDA, whose concentration reached 1.1 to 2.4 nmol z mg (dry weight) of cells21 after 30 min of illumination, and that the kinetics of this process paralleled cell death. Under these conditions, concomitant losses of 77 to 93% of the cell respiratory activity were also detected, as measured by both oxygen uptake and reduction of 2,3,5-triphenyltetrazolium chloride from succinate as the electron donor. The occurrence of lipid peroxidation and the simultaneous losses of both membrane-dependent respiratory activity and cell viability depended strictly on the presence of both light and TiO2. We concluded that TiO2 photocatalysis promoted peroxidation of the polyunsaturated phospholipid component of the lipid membrane initially and induced major disorder in the E. coli cell membrane. Subsequently, essential functions that rely on intact cell membrane architecture, such as respiratory activity, were lost, and cell death was inevitable.
 


Bactericidal mode of titanium dioxide photocatalysis

Z Huang, PC Maness, DM Blake, EJ Wolfrum… - … of Photochemistry and …, 2000 - Elsevier
When exposed to near-UV light, titanium dioxide (TiO2) exhibits a strong bactericidal activity. However, the killing mechanism(s) underlying the TiO2 photocatalytic reaction is not yet well understood. The aim of the present study is to investigate the cellular damage sites and their contribution to cell death. A sensitive approach using o-nitrophenol β-d–galactopyranosideside (ONPG) as the probe and Escherichia coli as model cells has been developed. This approach is used to illustrate damages to both the cell envelope and intracellular components caused by TiO2 photocatalytic reaction. Treatment of E. coli with TiO2 and near-UV light resulted in an immediate increase in permeability to small molecules such as ONPG, and the leakage of large molecules such as β-d–galactosidase after 20 min. Kinetic data showed that cell wall damage took place in less than 20 min, followed by a progressive damage of cytoplasmic membrane and intracellular components. The results from the ONPG assay correlated well with the loss of cell viability. Cell wall damage followed by cytoplasmic membrane damage leading to a direct intracellular attack has therefore been proposed as the sequence of events when microorganisms undergo TiO2photocatalytic attack. It has been found that smaller TiO2 particles cause quicker intracellular damage. Evidence has been obtained that indicated that the TiO2photocatalytic reaction results in continued bactericidal activity after the UV illumination terminates.


Titanium Dioxide: Toxic or Safe?

Titanium dioxide is the subject of new controversy, yet it is a substance as old as the earth itself. It is one of the top fifty chemicals produced worldwide. It is a white, opaque and naturally- occurring mineral found in two main forms: rutile and anatase. Both forms contain pure titanium dioxide that is bound to impurities. Titanium dioxide is chemically processed to remove these impurities, leaving the pure, white pigment available for use. Titanium dioxide has a variety of uses, as it is odorless and absorbent. This mineral can be found in many products, ranging from paint to food to cosmetics. In cosmetics, it serves several purposes. It is a white pigment, an opacifier and a sunscreen. Concern has arisen from studies that have pointed to titanium dioxide as a carcinogen and photocatalyst, thus creating fear in consumers. But are these claims true? What does the research on these allegations bear out? Would we as consumers benefit from avoiding this mineral to preserve our long-term health?

A carcinogen is a substance that causes a cellular malfunction, causing the cell to become cancerous and thus potentially lethal to the surrounding tissue and ultimately the body as these rapidly growing mutated cells take over. With the surge in cancer rates among all segments of the population, many people are attempting to reduce or eliminate their exposure to carcinogens. Titanium dioxide is regarded as an inert, non-toxic substance according to its Material Safety Data Sheet (MSDS).
 


Use of TiO2 photocatalytic process  for removal of airborne organic pollutants, VOCs appear to be superior to traditional technologies.
Applications of Photocatalytic Disinfection - HindawiJoanne Gamage and Zisheng Zhang

Department of Chemical and Biological Engineering, University of Ottawa, 161 Louis Pasteur, Ottawa, ON, K1N6N5, Canada

The photocatalytic process is well recognized for the removal of organic pollutants in the gaseous phase such as volatile organic compounds (VOCs), having great potential applications to contaminant control in indoor environments such as residences, office buildings, factories, aircrafts, and spacecrafts [4041].

To increase the scope of the photocatalytic process in application to indoor air, the disinfection capabilities of this technique are under investigation [39]. Disinfection is of importance in indoor air applications because of the risk of exposure to harmful airborne contaminants. Bioaerosols are a major contributor to indoor air pollution, and more than 60 bacteria, viruses, and fungi are documented as infectious airborne pathogens. Diseases transmitted via bioaerosols include tuberculosis, Legionaries, influenza, colds, mumps, measles, rubella, small pox, aspergillosis, pneumonia, meningitis, diphtheria, and scarlet fever [42]. Traditional technologies to clean indoor air include the use of activated charcoal filters, HEPA filters, ozonation, air ionization, and bioguard filters. None of these technologies is completely effective [20].

In the pioneering work by Goswami et al. [4344] investigating the disinfection of indoor air by photocatalysis, a recirculating duct facility was developed to inactivate biological contaminants in air with photocatalytic techniques. Experiments using Serratia Marcescens in air achieved a 100% destruction of microorganisms in a recirculating loop in 600 minutes [43]. This time was reduced to less than 3 minutes in later experiments [45].

Photocatalytic oxidation can also inactivate infectious microorganisms which can be airborne bioterrorism weapons, such as Bacillus anthracis (Anthrax) [4648]. A photocatalytic system was investigated by Knight in 2003 to reduce the spread of severe acute respiratory syndrome (SARS) on flights [49], following the outbreak of the disease. Similarly, in 2007 the avian influenza virus A/H5N2 was shown to be inactivated from the gaseous phase using a photocatalytic prototype system [39].


 Effective Photocatalytic Disinfection of E. coli K-12 Using AgBr−Ag−Bi2WO6Nanojunction System Irradiated by Visible Light: The Role of Diffusing Hydroxyl …
LS Zhang, KH Wong, HY Yip, C Hu, JC Yu… - … science & technology, 2010 - ACS Publications
Urgent development of effective and low-cost disinfecting technologies is needed to address the problems caused by an outbreak of harmful microorganisms. In this work, we report an effective photocatalytic disinfection of E. coli K-12 by using a AgBr−Ag−Bi2WO6 nanojunction system as a catalyst under visible light (λ ≥ 400 nm) irradiation. The visible-light-driven (VLD) AgBr−Ag−Bi2WO6 nanojunction could completely inactivate 5 × 107 cfu mL−1 E. coli K-12 within 15 min, which was superior to other VLD photocatalysts such as Bi2WO6 superstructure, Ag−Bi2WO6 and AgBr−Ag−TiO2 composite. Moreover, the photochemical mechanism of bactericidal action for the AgBr−Ag−Bi2WO6 nanojunction was investigated by using different scavengers. It was found that the diffusing hydroxyl radicals generated both by the oxidative pathway and the reductive pathway play an important role in the photocatalytic disinfection. Moreover, direct contact between the AgBr−Ag−Bi2WO6 nanojunction and bacterial cells was not necessary for the photocatalytic disinfection of E. coli K-12. Finally, the photocatalytic destruction of the bacterial cells was directly observed by TEM images and further confirmed by the determination of potassium ion (K+) leakage from the killed bacteria. This work provides a potential effective VLD photocatalyst to disinfect the bacterial cells, even to destruct the biofilm that can provide shelter and substratum for microorganisms and resist to disinfection.
 

Understanding the antimicrobial mechanism of TiO2-based nanocomposite films in a pathogenic bacterium

The incorporation of biocidal agents into engineered polymer-based nanocomposites has led to the development of versatile antimicrobial materials that are useful for a wide variety of packaging, biomedical and general use applications1,2,3,4,5. The development of such materials is difficult because thermodynamic and kinetic barriers inhibit the dispersal of inorganic, often hydrophilic, nanoparticles in hydrophobic polymer matrixes. Antimicrobial nanocomposites based on titania (TiO2) have been actively investigated in recent years. Upon photoactivation of the oxide component, the biocidal action is a result of the modulation of charge (electron-hole) carriers at the interface of the external surface of the material, yielding potent and long-lasting capabilities when the dispersion of the inorganic phase and organic-inorganic interfacial contact are optimally achieved6,7,8,9,10,11,12. Titania has substantial advantages over both chemical (NO, H2O2, small organic molecules) and metal (typically Ag)-based systems13,14. First, titania nanoparticles have a broad spectrum of activity against microorganisms, including Gram-negative and positive-bacteria and fungi, which is of particular importance for multiple drug resistant strains13,14. Second, and more importantly, titania-polymer nanocomposites are intrinsically environmentally friendly and exert a non-contact biocidal action. Therefore, no release of potentially toxic nanoparticles (with unpredictable effects on human health) to the media is required to achieve disinfection capabilities6,7,10,11,15,16.
 

Additional Peer Reviewed Studies Concerning the effect of TiO2 
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