A Tiny Approach to Green: New Nanotechnology Applications
While it doesn’t garner as many column inches as other industries – probably because it still seems like sci-fi to most people – the nanotechnology industry continues to expand out of the lab and into practical applications. Nanotechnology, the creation and use of devices that are between one and 100 nanometers wide (a nanometer is a billionth of a meter), is today worth an estimated $24 billion according to some research, and that figure is expected to rise steadily.
Industries that are beginning to make wide use of nanotechnology include biotechnology and pharmaceuticals, aerospace, chemical, electronics and information technology, space exploration, textiles and even cosmetics and skincare. (One of the most oft-cited examples of nanotech in consumer products is its use in high SPF sunscreens.)
The green tech industry is no exception, and as of late, it has begun to use nano-materials in areas like coatings, solar cells, insulation and clean alternative fuels. Many of these technologies – the most interesting are summarized below – are emerging from laboratories where they might have once languished for years or decades, and are immediately finding investment funds from a combination of government programs and private industry.
One of the most exciting applications for nanotechnology is printed electronics, a technology that enables tiny electronic devices to be literally printed, using more or less traditional printing process, onto materials such as paper, plastic and textiles, enabling electronics processes that just aren’t feasible with traditional silicon-based electronics.
The process, which uses special electrically functional inks, is expected to be a boon to product security, supply chain management and inventory systems, particularly when combined with radio frequency identification (RFID).
But the technology has a green application as well: nanoparticles used in the manufacture of solar calls have the potential to dramatically cut manufacturing costs. The lower-temperature process can replace the current high temperature vacuum deposition process that is used to manufacture more conventional solar cells made with crystalline semiconductor materials. Lower manufacturing costs for solar cells will bring costs down and enable a wider market penetration. In addition, newer processes will allow solar cells to be literally “printed” onto glass and other building materials, perhaps ultimately eliminating the need for separate, costly solar panels. The process will also allow solar cells to be applied to curved surfaces unsuitable for traditional solar panels, such as the roof of a car, truck or military utility vehicle.
Less Toxic Flame Retardants
Flame retardants, mandated by federal law on everything from building materials to computer casings to children’s pajamas, have a huge drawback: toxicity. Many of these halogenated chemicals have been linked to a host of health problems from cancer to thyroid disease to reproductive issues. Their presence in common household products such as carpeting, bedding and clothing is responsible for a lot of toxic indoor air pollution.
Scientists at the Agricultural Research Service (ARS) Southern Regional Research Center in New Orleans are using nanotechnology to treat cotton for fireproofing, with all of the benefits and none of the toxic side effects. The ARS, the chief intramural scientific research agency of the USDA, has been on a push to find alternatives to chemical flame retardants: materials that are both non-toxic and effective and that won’t stiffen cotton, as traditional chemicals do.
The ARS researchers recently teamed with Texas A&M University scientists to produce a new substance made of water-soluble polymers snf 50- to 100-nanometer clay particles. Applied to fabric, the flame-retardant properties work by a process called “intumescence”: when exposed to open flame, it quickly forms a swollen and charred outer layer that stops the flame from reaching underlying or nearby fibers. During testing, researchers found that as much as 95 percent of cotton fabric treated with the coating remained intact after exposure to flame.
Nanoparticles Help Target Chemotherapy Precisely
Chemotherapy is a “shock and awe” kind of treatment. Large amounts of cancer-destroying drugs are introduced into a patient’s body to shrink a tumor or inhibit cancer cells. Unfortunately, chemotherapy drugs are not particular about which tissues they attack, hence the unpleasant side-effects. It’s akin to flooding a 10-acre field in order to put out a tiny brush fire in the middle of the field.
Another team of researchers from the University of Central Florida has found a way to create nanoparticles that can precisely target only the cancer cells, sparing the other organs from the toxic effects of the drugs. UCF Assistant Professor J. Manuel Perez and his team used a common chemotherarpy drug called Taxol, known for its toxic side effects, in cell culture studies. They modified nanoparticles to carry Taxol directly to the cancer cells and only to the cancer cells, potentially allowing for precisely targeted cancer treatment that does not damage healthy cells. To achieve the precise targeting, researchers attached a folic acid derivative – a substance cancer cells are really keen on – to the drug-carrying nanoparticle, helping it find its way directly to the cancer. By treating the nanoparticles with a fluorescent dye and an iron oxide magnetic core, researchers are then able to use optical imaging and magnetic resonance imaging (MRI) to track the drug-carrying nanoparticles’ location and the progress of the treatment.
This is significant not only from a treatment perspective, but also from a cost standpoint. Many chemotherapy drugs have poor solubility in the body, with the result being that patients need to be loaded up with them to gain any benefit. Not only does this damage healthy tissue and make the patient sick, it means the drugs must contain high amounts of their active ingredients, which drives up the costs of these drugs. By directly targeting cancer cells with tiny amounts of medication, it could ultimately drive down costs. From a green standpoint, it would also reduce the amount of residual drug cancer patients are flushing into the world’s water supply.
Green Building Coatings
It’s no secret that the green building industry is soaring, and for good reason. According to the U.S. Department of Energy, commercial and residential buildings account for about 40 percent of all energy used in the U.S. As energy becomes scarce and more expensive, interest in green building broadens, as does demand for newer, cheaper green building technologies. By some estimates, the green building materials industry has grown to $156 billion a year industry and is expected to climb much higher.
While it’s not hard to find news about sexy new green buildings, what about the millions of existing buildings that need a bit of a green boost? A company called Industrial Nanotech, Inc. has developed a water-based nanotechnology coating product called Nansulate that can literally be painted onto existing building surfaces. The product comes in a bucket and can be applied with an airless sprayer to roofs, windows, interior and exterior walls and other places heat escapes.
Applied to windows, the nanotech coating lets light in, but reduces heat transfer through the glass. On walls, it acts as thermal insulation and can also prevent corrosion, offer flame resistance, cut down on mold growth and encapsulate lead and other harmful substances often found in buildings, preventing them from leaching into the ground.
Another up-and-coming application of nanotech, as reported in the journal Nature, was recently demonstrated by a team at Princeton University led by Michael McAlpine. The researchers took a piece of graphene – a one-atom thick sheet of carbon – and planted specially designed peptides, a sequence of amino acids, onto the graphene. They then “bio-transferred” the graphene onto tooth enamel. News reports branded it “tooth tattooing.”
Once on the tooth, the peptide/graphine device was able to detect bacteria in the mouth and wirelessly monitor the wearer’s oral health. Thanks to the antimicrobial peptides and a resonant coil, the device was able to pick up and detect individual bacteria cells and transmit the information to medical staff via RFID technology without need of a separate power source or a wired connections. In one test, a research student breathed onto one of the sensors that had been implanted on a cow’s tooth and the device detected molecules of bacteria on his breath.
The sensors may not be limited to teeth, however. The research team believes they could be used, for example, by military personnel in the field to determine whether a wound has become infected, or in hospitals where patients with weakened immune systems are extra vulnerable to nosocomial (hospital-acquired) infections.
Water desalination is a tricky business. Because it uses enormous amounts of energy, it only really makes sense on a very large scale. Sea water is salty because of ions, so the typical desalination process works by using very fine membranes to separate the water from the ions. While individuals can desalinate very small amounts of water by rather inefficient evaporation processes, the faster ionic separation is generally left for commercial plants. A team MIT researchers, however, has discovered a new way to separate the ions from the salt water using nanotechnology. Their research was published in Nature Naotechnology.
While traditional ionic separation is a physical process, the new method uses an electric barrier made of a very tiny nanoscale fluidic channel that, when negatively charged, repels the ions, letting the fresh water pass through. (The process doesn’t remove contaminants, however, so it must be used in conjunction with filtering.) The most attractive part of the new process is that the equipment is small and portable. A single unit can produce about 12 liters of water an hour, say researchers, and several units set up to work together can produce enough fresh water for a small community.
“It has a power efficiency that more or less matches that of current state-of-the-art reverse osmosis plants,” Jongyoon Han, associate professor of Biological Engineering at MIT, told Nanowerk. “In a single-step operation, 99 percent of the salt contained in the sea water is removed, with 50 percent of the incoming sea water being recouped as desalted water.”
Reducing the Eco Impact of Pressure-Treated Wood
Pressure-treated wood is great stuff – you’d never build your deck with anything else (unless you can afford teak) – but the chemicals used to preserve it from decay can leach out and contaminate soil. Researchers from Michigan Tech University, backed with funding from the U.S. Environmental Protection Agency (EPA), have found a way to use nanotechnology to seal pressure-treated wood and encapsulate the chemicals. The team used nanoparticles that are actually ultra-tiny spheres of gelatin or chitosan (which comes from the shells of crustaceans), and chemically modified the materials to surround the fungicide tebuconazole, which is added to pressure-treated wood to keep it from rotting.
The team’s tests, carried out in the warm, muggy weather of Hawaii, revealed that the wood treated with the nanoparticle coating was just as resistant to rot and bugs as conventionally treated lumber, but reduced the amount of unsavory chemicals leaching into the soil nearby by about 90 percent.
Portable, Mobile Air Testing
Imagine being able to whip out your cell phone and determine whether the air around you is safe to breathe. While that’s a bit of an exaggeration, a professor at the University of California’s Riverside Bourns College of Engineering has used nanotechnology to develop a process that could essentially create mobile apps to detect harmful airborne substances in real-time, according to Nanowerk.
The technology, which uses functionalized carbon nanotubes 100,000 times finer than a human hair, is under development by Nosang Myung, professor and chair of the Department of Chemical and Environmental Engineering, and Innovation Economy Corporation. The researchers agree the process would have numerous applications, such as in agriculture (detecting unsafe concentrations of pesticides), industrial processes, dangerous material storage (to monitor for evaporation and leaks) and homeland security and military installations (testing for weaponized biological or chemical substances).
Nano Engineering Applications, Inc., which was created and funded by Innovation Economy Corporation, plans to license Myung’s research and commercialize it. The goal is to translate the process into portable devices – small enough to fit onto phones or other handheld equipment – that can quickly detect dangerous airborne substances in miniscule amounts.
Investment Pace In Nano Is Picking Up
The good news is that investment in nanotech projects such as these is sharply up, and a number of organizations are working to put investment capital cash behind projects while they are still in the lab.
One such group, the NanoMaterials Commercialization Center in Pittsburgh, says it supports early-stage companies with promising ideas developed at the nanoscale. The center recently joined forces with The Nanotechnology Institute, a similar organization in Philadelphia.
“We’re not looking for small steps,” says Leoné Hermans-Blackburn, executive director of the NanoMaterials Center. “We’re looking for significant, impactful technologies.”
The federal government is in agreement. A number of federal agencies are increasing the funds available for nanoscale research and investments through dozens of programs, many of them coordinated by the National Nanotechnology Coordination Office, which says its role is to help the federal government transition from simply advancing the field to producing workable applications.
So, while many green advocates are fond of saying that alternative energy and green tech projects won’t serve their purpose until they are adopted on a large scale, some of the biggest advancements in green tech may start out very small…about a nanometer wide, in fact.