In the last few decades, scientists around the world have been experimenting with potentially revolutionary new materials. An impressive number of advanced materials have been uncovered, and many of them have exceptional properties. Smart materials, for instance, are a category of advanced materials with fascinating features. They include self-healing materials such as the self-healing concrete, memory metals that revert to their original forms when heated, and piezoelectric crystals and ceramics that can produce electricity from pressure. While these smart materials have considerable potential for future applications, their effects are anticipated to be overshadowed by the impact of nanomaterials.
Nanomaterials are substances that have least one structural dimension less than 100 nm. This is roughly equivalent to the molecular level, with one nanometer being equal to a billionth of a meter. The value of nanomaterials lies in the fact that at nanoscales, many ordinary materials develop spectacular new properties, such as superconductivity or magnetism. Furthermore, all nanoparticles are governed by the rules of quantum mechanics and have a significantly large surface area per unit of volume. This property makes nanoparticles highly reactive.
Simple nanoparticles are found in many products today. For example, the antimicrobial properties of nanosilver make it excellent for use in detergents and odor-resistant socks. Zinc oxide has unique wavelength-blocking characteristics and is an important constituent of many sunscreens. Clay nanoparticles are used to make composites that are stronger and more elastic, making them useful for car bumpers.
Advanced nanoparticles, being much more expensive, currently have a limited number of applications. However, health care is one area that could soon experience a strong impact from the use of advanced nanomaterials. The phenomenal reactivity of nanoparticles makes them excellent candidates for use in diagnostic tools as well as in targeted drug delivery. In cancer patients, the efficacy of chemotherapy could be greatly enhanced by using nanoparticles to concentrate drugs inside cancer cells. Not only would this improve the efficacy of the drug, but could also potentially reduce many of the side-effects, allowing higher doses to be administered without harming the patient. For example, tumor necrosis factor, or TNF, is a potent antitumor agent that is also highly toxic. AstraZeneca is developing a therapy that will use gold nanoparticles to deliver TNF directly into cancer beds. Another pharmaceutical company Celgene has already developed a nanoparticle-bound formulation of paclitaxel, making it the first chemotherapy drug of its kind. 1 With the potential for extending the lives of millions of people, nano-based anticancer drugs could create an economic impact of as much as $500 billion per year by 2025.2
Graphene and carbon nanotubes are two other advanced nanoparticles. These nanomaterials are essentially units of ultrathin single-atom layers of carbon. While both graphene and nanotubes are prohibitively expensive to manufacture, they possess an extraordinary combination of properties. For instance, not only is graphene ten times as conductive as copper, it also only a sixth the density of steel while being a hundred times as strong. Moreover, graphene is extremely elastic and can revert to its original shape even after being subjected to extremes of pressure. With these remarkable specifications, graphene could one day replace silicon in microchips to create processors that are a 1000 times faster than the best ones currently available.
Today, graphene is being used to develop supercapacitors that will potentially lead to batteries with extremely high performance. Such batteries would keep devices like smartphones powered for weeks on end, 3 and could be recharged with a few seconds. Furthermore, graphene-based lithium ion batteries would be more efficient, potentially accelerating the adoption of electric-powered vehicles. The scope of the potential applications of graphene is endless. In fact, with its absorptive properties, graphene may also prove to be an effective means of purifying water. Lockheed Martin is currently developing graphene-based water filters that could convert sea water into potable water at a fraction of the cost of existing methods.4
Carbon nanotubes also have great potential. With their large surface areas and high reactivity, they make for excellent sensors. In health care, nanotubes could be used to augment the sensitivity of existing techniques for detecting biomarkers, such as those for cancer. They could also be used to detect minute levels of noxious substances in the environment. Additionally, nanotubes could be integrated with graphene to create thin, flexible, and transparent display screens.
Quantum dots are another type of nanomaterial. They are semiconductors with unique optical properties, and can emit light in different colors. The potential applications include electronic displays, and medical diagnostic tools, whereby contrast dyes could be replaced by quantum dots that light up under imaging.
Nanomaterials are still in their infancy and most of their impact on the world is not likely to be significantly appreciable in the near-term. One of the greatest obstacles to achieving the full potential of advanced nanomaterials is in the cost of production. Graphene films can cost as much as $819 a unit, while nanotubes go for up to $700 per gram. Large scale production of applications using these materials is greatly constrained by the expense. In addition to the cost, there are also significant technological barriers preventing the production of high-quality nanomaterials. For example, it’s still quite difficult to create long nanotubes or larger graphene sheets of good quality.
Finally, there is significant concern that loose nanoparticles may damage the environment, or even prove hazardous to health. We already have evidence that inhaled nanotubes could be just as dangerous to the lungs as asbestos. 5 As nanomaterial applications become more widespread, governments will play a key role in regulating the technology to ensure the safety of its citizens.
Matthew Herper, Celgene’s Abraxane extends life by 1.8 months in advanced pancreatic cancer, Forbes, January 22, 2013.
McKinsey Global Institute, Disruptive technologies: Advances that will transform life, business, and the global economy, May 2013
Maher El-Kady and Richard Kaner, Scalable fabrication of high-power graphene microsupercapacitors for flexible and on-chip energy storage, Nature Communications, volume 4, February 2013.
Paul Borm and Wolfgang Kreyling, Toxicological hazards of inhaled nanoparticles—Potential implications for drug delivery, Journal of Nanoscience and Nanotechnology, volume 4, number 5, October 2004.