Size of the Nanoscale

Just how small is “nano?” In the International System of Units, the prefix "nano" means one-billionth, or 10^-9; therefore one nanometer is one-billionth of a meter. It’s difficult to imagine just how small that is, so here are some examples:

·         A sheet of paper is about 100,000 nanometers thick

·         A strand of human DNA  is 2.5 nanometers in diameter

·         There are 25,400,000 nanometers in one inch

·         A human hair is approximately 80,000- 100,000 nanometers wide

·         A single gold atom is about a third of a nanometer in diameter

·         On a comparative scale, if the diameter of a marble was one nanometer, then diameter of the Earth would be about one meter

·         One nanometer is about as long as your fingernail grows in one second

The illustration below has three visual examples of the size and the scale of nanotechnology, showing just how small things at the nanoscale actually are.

Standards for Nanotechnology

Nanotechnology relies on standards through at least three concepts:
1.       Documentary standards define agreed-upon terminology or standard language for a field of science, engineering, or technology; they are agreed-upon means for conducting measurements; agreed-upon performance characteristics of instruments or commercial products; and particularly, they are documented agreements on means to facilitate trade and commerce.
2.       Standards often refer to standard reference materials, materials that are certified by a national standards laboratory to have specified characteristics traceable to an international system of the fundamental system of physical units of measurement.
3.       Standards generally refer to the fundamental physical realization of the units of measurement defined in the International System of Units (SI).

The SI's base units of standards are widely accepted in science and technology and set measurement standards agreed to through the Convention of the Meter, a diplomatic treaty between fifty-four nations. The International Bureau of Weights and Measures (BIPM), located in Sèvres near Paris, France, has the task of ensuring world-wide uniformity of measurements and their traceability to the SI basic units.

There are seven base quantities: length, mass, time, electric current, thermodynamic temperature, amount of substance, and luminous intensity. Although these seven quantities are by convention regarded as independent, their respective base units—the meter, kilogram, second, ampere, kelvin, mole, and candela—are in a number of instances interdependent. In nanotechnology all the base units have relevance to the instruments used and the measurements performed by researchers in academia, government, and industry. These base units also form the foundation for commerce and business. In particular, the unit of length at the nanoscale, the nanometer, is derived from the base unit meter by subdividing the meter by a factor of one billion. Another unit derived from the base units that is of particular use in nanotechnology is the unit of force, the Newton. The force exerted by the cantilevers used in atomic force microscopes is typically specified in terms of nanoNewtons or one-billionth of a Newton.  (For reference, a Newton is force about equal to the weight of an apple.)

The SI globally accepted nanotechnology standards are vital to continued progress in the field’s research and development, and for safe, secure, and responsible commercialization of nanotechnology in the years ahead. Standards are important to businesses, consumers, and researchers.

Ethical,Legal, and Societal Issues

Responsible development of nanotechnology is one of the four goals of the NNI and central to advancing the other three (specifically, continuing a world-class R&D program; fostering the transfer of new nanotechnologies into products for commercial and public benefit; and educating the workforce, engaging the public, and sustaining an effective nanotechnology R&D infrastructure).  

An important component of responsible development is the consideration of the ethical, legal, and societal implications of nanotechnology. How nanotechnology research and applications are introduced into society; how transparent decisions are; how sensitive and responsive policies are to the needs and perceptions of the full range of stakeholders; and how ethical, legal, and social issues are addressed will determine public trust and the future of innovation driven by nanotechnology.

The NNI is committed to fostering the development of a community of experts on ethical, legal, and societal issues (ELSI) related to nanotechnology and to building collaborations among ELSI communities, such as consumers, engineers, ethicists, manufacturers, nongovernmental organizations, regulators, and scientists. These stakeholder groups will consider potential benefits and risks of research breakthroughs and provide their perspectives on new research directions. With its industry stakeholders, the NNI will also develop information resources for ethical and legal issues related to intellectual property and ethical implications of nanotechnology-based patents and trade secrets. To date, the cumulative NNI investments in education and societal dimensions totals $350 million.

To help explore the ELSI issues, NNI agencies are supporting the two centers for nanotechnology in society noted in the "Related Resources" box, and where possible, are incorporating ELSI components into their new nanotechnology R&D programs.

Future Transportation Applications

In addition to contributing to building and maintaining lighter, smarter, more efficient, and “greener” vehicles, aircraft, and ships, nanotechnology offers various means to improve the transportation infrastructure:

·         Nano-engineering of steel, concrete, asphalt, and other cementitious materials, and their recycled forms, offers great promise in terms of improving the performance, resiliency, and longevity of highway and transportation infrastructure components while reducing their cost. New systems may incorporate innovative capabilities into traditional infrastructure materials, such as the ability to generate or transmit energy.

·         Nanoscale sensors and devices may provide cost-effective continuous structural monitoring of the condition and performance of bridges, tunnels, rails, parking structures, and pavements over time. Nanoscale sensors and devices may also support an enhanced transportation infrastructure that can communicate with vehicle-based systems to help drivers maintain lane position, avoid collisions, adjust travel routes to circumnavigate congestion, and other such activities.

Nanobiosystems,Medical, and Health Applications

Nanotechnology has the real potential to revolutionize a wide array of medical and biotechnology tools and procedures so that they are more personalized, portable, cheaper, safer, and easier to administer. Below are some examples of important advances in these areas.

·         Quantum dots are semiconducting nanocrystals that can enhance biological imaging for medical diagnostics. When illuminated with ultraviolet light, they emit a wide spectrum of bright colors that can be used to locate and identify specific kinds of cells and biological activities. These crystals offer optical detection up to 1,000 times better than conventional dyes used in many biological tests, such as MRIs, and render significantly more information.

·         Nanotechnology has been used in the early diagnosis of atherosclerosis, or the buildup of plaque in arteries. Researchers have developed an imaging technology to measure the amount of an antibody-nanoparticle complex that accumulates specifically in plaque. Clinical scientists are able to monitor the development of plaque as well as its disappearance following treatment (see image).

·         Gold nanoparticles can be used to detect early-stage Alzheimer’s disease.

·         Molecular imaging for the early detection where sensitive biosensors constructed of nanoscale components (e.g., nanocantilevers, nanowires, and nanochannels) can recognize genetic and molecular events and have reporting capabilities, thereby offering the potential to detect rare molecular signals associated with malignancy

.·         Multifunctional therapeutics where a nanoparticle serves as a platform to facilitate its specific targeting to cancer cells and delivery of a potent treatment, minimizing the risk to normal tissues.

·         Research enablers such as microfluidic chip-based nanolabs capable of monitoring and manipulating individual cells and nanoscale probes to track the movements of cells and individual molecules as they move about in their environments.

·         Research is underway to use nanotechnology to spur the growth of nerve cells, e.g., in damaged spinal cord or brain cells. In one method, a nanostuctured gel fills the space between existing cells and encourages new cells to grow. There is early work on this in the optical nerves of hamsters. Another method is exploring use of nanofibers to regenerate damaged spinal nerves in mice.

Environmental Remediation Applications

Besides lighter cars and machinery that requires less fuel, and alternative fuel and energy sources, there are many eco-friendly applications for nanotechnology, such as materials that provide clean water from polluted water sources in both large-scale and portable applications, and ones that detect and clean up environmental contaminants.

·         Nanotechnology could help meet the need for affordable, clean drinking water through rapid, low-cost detection of impurities in and filtration and purification of water. For example, researchers have discovered unexpected magnetic interactions between ultrasmall specks of rust, which can help remove arsenic or carbon tetrachloride from water (see image); they are developing nanostructured filters that can remove virus cells from water; and they are investigating a deionization method using nano-sized fiber electrodes to reduce the cost and energy requirements of removing salts from water.

• Nanoparticles will someday be used to clean industrial water pollutants in ground water through chemical reactions that render them harmless, at much lower cost than methods that require pumping the water out of the ground for treatment.
• Researchers have developed a nanofabric "paper towel," woven from tiny wires of potassium manganese oxide, that can absorb 20 times its weight in oil for cleanup applications.
• Many airplane cabin and other types of air filters are nanotechnology-based filters that allow “mechanical filtration,” in which the fiber material creates nanoscale pores that trap particles larger than the size of the pores. They also may contain charcoal layers that remove odors. Almost 80% of the cars sold in the U.S. include built-in nanotechnology-based filters.
• New nanotechnology-enabled sensors and solutions may one day be able to detect, identify, and filter out, and/or neutralize harmful chemical or biological agents in the air and soil with much higher sensitivity than is possible today. Researchers around the world are investigating carbon nanotube “scrubbers,” and membranes to separate carbon dioxide from power plant exhaust. And researchers are investigating particles such as self-assembled monolayers on mesoporous supports (SAMMS™), dendrimers, carbon nanotubes, and metalloporphyrinogens to determine how to apply their unique chemical and physical properties for various kinds of toxic site remediation.

Sustainable Energy Applications

The difficulty of meeting the world’s energy demand is compounded by the growing need to protect our environment. Many scientists are looking into ways to develop clean, affordable, and renewable energy sources, along with means to reduce energy consumption and lessen toxicity burdens on the environment.

·         Prototype solar panels incorporating nanotechnology are more efficient than standard designs in converting sunlight to electricity, promising inexpensive solar power in the future. Nanostructured solar cells already are cheaper to manufacture and easier to install, since they can use print-like manufacturing processes and can be made in flexible rolls rather than discrete panels. Newer research suggests that future solar converters might even be “paintable.”

• Nanotechnology is improving the efficiency of fuel production from normal and low-grade raw petroleum materials through better catalysis, as well as fuel consumption efficiency in vehicles and power plants through higher-efficiency combustion and decreased friction.
• Nano-bioengineering of enzymes is aiming to enable conversion of cellulose into ethanol for fuel, from wood chips, corn stalks (not just the kernels, as today), unfertilized perennial grasses, etc.
• Nanotechnology is already being used in numerous new kinds of batteries that are less flammable, quicker-charging, more efficient, lighter weight, and that have a higher power density and hold electrical charge longer. One new lithium-ion battery type uses a common, nontoxic virus in an environmentally benign production process.
• Nanostructured materials are being pursued to greatly improve hydrogen membrane and storage materials and the catalysts needed to realize fuel cells for alternative transportation technologies at reduced cost. Researchers are also working to develop a safe, lightweight hydrogen fuel tank.
• Various nanoscience-based options are being pursued to convert waste heat in computers, automobiles, homes, power plants, etc., to usable electrical power.
• An epoxy containing carbon nanotubes is being used to make windmill blades that are longer, stronger, and lighter-weight than other blades to increase the amount of electricity that windmills can generate.
• Researchers are developing wires containing carbon nanotubes to have much lower resistance than the high-tension wires currently used in the electric grid and thus reduce transmission power loss.
• To power mobile electronic devices, researchers are developing thin-film solar electric panels that can be fitted onto computer cases and flexible piezoelectric nanowires woven into clothing to generate usable energy on-the-go from light, friction, and/or body heat.
• Energy efficiency products are increasing in number and kinds of application. In addition to those noted above, they include more efficient lighting systems for vastly reduced energy consumption for illumination; lighter and stronger vehicle chassis materials for the transportation sector; lower energy consumption in advanced electronics; low-friction nano-engineered lubricants for all kinds of higher-efficiency machine gears, pumps, and fans; light-responsive smart coatings for glass to complement alternative heating/cooling schemes; and high-light-intensity, fast-recharging lanterns for emergency crews.