by Mark Sisson — June 2015—It turns out that when you change the scale of certain materials, new and amazing properties emerge. Microfiber cloths, for example, have had a tremendous impact in our world of cleaning, and for good reason. When you change the scale of the threads in a cloth, making them super small, a new set of physical forces come in to play.
Van der Waals forces, the same forces that allow geckos to stick to glass with millions of microscopic hairs on their feet, create a very small attraction between the threads and various contaminant particles. While these individual forces of attraction are small, there are millions of threads, creating an almost vacuum like effect on particles.
Nanotechnology is even smaller, measured in nanometers or 1 billionth of a meter.
Microfiber & Other Nanos
What does microfiber have to do with nanotechnology, you might ask. Well, it’s all about how physical properties of materials change dramatically at extremely small scales. Take water, for instance. In our macro-world, water is simply wet. But zoom in to the molecular level, and water is electrically imbalanced, allowing the molecule to stick to all kinds of different particles and break them down. Combine this fact and the natural solvent action of water molecules with the attraction of microfiber, and you have an extremely versatile and environmentally-friendly cleaning system utilizing these special micro-properties.
The individual threads in a microfiber cloth are 1/100 the size of a human hair. But if we turned on our superman vision and could see them at a nanoscale, these fibers would be huge.
Many materials at the nano scale behave in surprising, and sometimes very beneficial ways. One such material is titanium dioxide. In its normal form, Ti02 is the most widely used white pigment in the world. It is added to everything from paints to milk and toothpaste. And it’s a valuable additive in sunscreen because of its ability to block UV rays. But just like the threads in a microfiber cloth, when Ti02 is manufactured as a nanoscale particle, some amazing reactions are created.
Self-Cleaning? You’ve Got It!
While the discovery that nanoscale Ti02 creates a photocatalytic oxidation effect under UV light was first documented in 1971, the science has come a long way in 40 years. Today, specific forms of nano Ti02 produce a powerful photocatalytic oxidation reaction using nothing but normal indoor light. The nano crystals that create this reaction are around 8 nanometers. To put it into perspective, DNA is around 2 nanometers, a typical bacteria 200 nanometers, and that microfiber cloth thread is a whopping 1,000 nanometers. If we put on our cleaning hats for a minute, it’s not too difficult to imagine how useful a substance could be that creates an oxidation reaction from light. Could this be the Holy Grail for cleaners? Could this create surfaces that oxidize contaminants and kill pathogens automatically… dare I say “self-cleaning” surfaces? It seems like science fiction, but that’s exactly how far this technology has come.
Because of the popularity of Ti02 and the advent of nanoscale particles, there has been some speculation about toxicity to humans. Most of the studies to date have been focused on the predominant risk, which is the inhalation of a large amount of nano-Ti02 dust in a manufacturing environment. With the correct application and material science, self-cleaning surfaces involve Ti02 that is molecularly bonded to the underlying material, preventing its release into the environment and creating a long lasting self-cleaning effect.
The self-cleaning process actually happens in multiple ways. First, the basic oxidation process happens directly with any organic material that comes in contact with the surface, breaking down the contaminant into base elements like water and carbon dioxide. The second process, which will be of special interest to infection-prevention professionals, involves the oxidation of water molecules, which produce hydroxyl radicals.
While hydroxyl radicals have extremely short lifespans, existing for less than 1 millionth of a second, they are extremely deadly to microorganisms like bacteria, viruses, and fungi. And because the process is oxidative rather than enzymatic or antibiotic, the surface doesn’t contribute to antimicrobial resistance or “super bugs.” As a side benefit, the oxidation process also continuously eliminates volatile organic compounds (VOCs) and has even been shown to eliminate greenhouse gases, such as methane and ozone.
What does this really mean to the cleaning industry and how can this help us clean for wellness rather than just appearance? First, by oxidizing organic material, like bacteria and viruses, we can create a surface that doesn’t just look clean…it’s truly clean at a microscopic scale. In too many cases, outbreaks from a specific pathogen happen in facilities that look perfectly clean. It’s human nature to think a surface is clean when we can’t see any dirt. But it’s all of those nasty bugs we can’t see that cause problems.
To put the issue into perspective, most hospitals look spotless, yet 100,000 people die each year from health care acquired infections (HAI). Think of nanotechnology as billions of solar powered nanobots, zapping those microscopic HAI-inducing monsters that are invisible to the naked eye. And because these nanobots are catalysts, nothing gets used up or gets released into the environment like some traditional antimicrobials based on toxins or heavy metals. Secondly, photocatalytic nanotechnology doesn’t rely on the diligence of people to be effective. Let’s face it, humans are often unreliable, or at least inconsistent, when given specific tasks. Are your cleaning personnel properly trained? Are they being monitored to determine whether their work is effective? Do they always following the dilution and application instructions for the various disinfectants and cleaners that are being used? Deploying technology as part of the cleaning process can help overcome some of these issues and create a more consistent and effective cleaning system.
Built to Clean
So how can businesses benefit from the latest advancements in self-cleaning nanotechnology? For the last decade or so, photocatalytic nanotechnology has been used as an external coating for buildings. What’s funny is that these coatings weren’t being used to kill germs or clean for wellness. They were used purely to keep the exterior of buildings looking cleaner, and they accomplished this through another unique property of this nanomaterial. Titanium dioxide happens to be super hydrophilic, meaning it’s an amazing wetting agent, encouraging water to create a thin film on the surface rather than beading up. Particles get picked up by this film of water, rinsing visible dirt away each time it rains.
In the last couple of years, a small number of companies have started applying this type of nanotechnology inside buildings. In health care, for instance, there are critical, semi-critical, and noncritical surfaces. For the most part, only critical surfaces have been the focus of this type of service because of the relatively high cost of application. However, nanotechnology-based products for high-traffic touch points are proving cost effective for noncritical surfaces in health care as well as education, hospitality, and food service.
In a recent study by Dr. Charles Gerba, microbiologist at the University of Arizona, a single touch point, such as a door handle, was inoculated with a harmless bacteria surrogate. Within two to four hours, between 40 percent and 60 percent of the contact surfaces in the entire office building were contaminated. The bottom line is that many common germs are spread by touching surfaces that have been contaminated from a previous touch. This is where nanotechnology-based self-cleaning surfaces really shine.
Traditional cleaning and disinfection is basically a one-time kill. Can you imagine your cleaning staff having to disinfect a door handle after each and every touch? Just like robots handle repetitive tasks in manufacturing with great efficiency and reliability, these “nanobots” can work to clean a surface after every touch…without mistakes, coffee breaks, or management.
We’re all business people here, right? So it’s not likely that we’re going to spend our budget on initiatives that are only good for people or the planet. We need return on investment, and that’s where cleaning for wellness adds value. Just pick an industry…any industry…and you’ll find businesses struggling to keep down costs associated with illness. The cost of absenteeism in schools averages US$500 per teacher and $110 per student. In businesses, that figure is $1,685 per employee. And in healthcare, we spend an estimated $30 billion annually to treat HAIs.
With only about 50 percent of people washing their hands after using the restroom (a sad but true fact), hand hygiene is a dominant issue in today’s discussion. But let’s look more closely at that in real-world terms.
Let’s say we improve hand washing compliance to 70 percent, 80 percent, or even 90 percent. That would be a tremendous achievement, right? But at a compliance rate of 90 percent, you still have one out of 10 people contaminating nearly every surface they touch, negating much of the effort the other nine people have made to keep their hands clean. This spreading of germs is exacerbated when you have sick employees come to work, or “presenteeism,” as described in ISSA’s Value of Clean (www.issa.com/value).
One hot area of research is in developing material science that accentuates the photocatalytic action. Surface textures and properties can help to attract and trap pathogens so that the nanotechnology can do the killing faster and more thoroughly. In our research over the last three years, this type of holistic approach, combining special substrates, primers, and Ti02, has resulted in reliable three log reductions for E. Coli and S. Aureus (each log equals a 90 percent reduction). And in one test using the human Coronavirus, which was done for Saudi Arabia during the MERS outbreak, all virus cells were killed somewhere under 30 minutes.
Not surprisingly, the efficacy of this technology is getting better at a rapid pace. New approaches using additives to Ti02 are producing impressive results. A recent independent lab test we conducted using new formula prototypes produced a 99.9998 percent reduction in Staph A…almost a six log reduction! None of us want a sterile environment, but nanotechnology provides a powerful approach to disinfection that has the potential to create cleaner, healthier surfaces exactly where and when they are needed around the clock. The next big thing in cleaning might just be something very small indeed.
Mark Sisson is co-founder of NanoTouch Materials, which manufactures a line of self-cleaning NanoSeptic surfaces for facility management, health care, education, and food service. He can be reached at firstname.lastname@example.org or visit www.nanoseptic.com.