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Guidance for Industry 1

June 2014

Contains Nonbinding Recommendations

I. Introduction and Scope II. Discussion A. Points to Consider B. Rationale for Elements within the Points to Consider III. Conclusion IV. References

Nanotechnology is an emerging technology that can be used in a broad array of FDA-regulated products, including medical products (e.g. to increase bioavailability of a drug), foods (e.g., to improve food packaging) and cosmetics (e.g. to affect the look and feel of cosmetics). Materials in the nanoscale range (i.e., with at least one dimension in the size range of approximately 1 nanometer (nm) to 100 nm) can exhibit different chemical or physical properties, or biological effects compared to larger-scale counterparts. For example, dimension-dependent properties or phenomena may be used for functional effects such as increased bioavailability, decreased dosage, or increased potency of a drug product, decreased toxicity of a drug product, better detection of pathogens, more protective food packaging materials, or improved delivery of a functional ingredient or a nutrient in food (Refs. 1-6). These effects may derive from altered chemical, biological, or magnetic properties, altered electrical or optical activity, increased structural integrity, or other unique characteristics of materials in the nanoscale range not normally observed or expected in larger-scale materials with the same chemical composition (Ref. 7). Materials or end products may also exhibit similar properties or phenomena attributable to a dimension(s) outside the nanoscale range of approximately 1 nm to 100 nm (Refs. 27-30; see also discussion in Section II.B.5).

For the purpose of this guidance only, references to products that involve the application of nanotechnology or nanotechnology products mean products that contain or are manufactured using materials in the nanoscale range, as well as products that contain or are manufactured using certain materials that otherwise exhibit related dimension-dependent properties or phenomena. Likewise, we use the term nanomaterial generally to refer to both materials in the nanoscale range and certain materials that otherwise exhibit related dimension-dependent properties or phenomena. Use of these terms is for the purpose of communicating FDAs current thinking elaborated in this document only.

As used in this guidance, the word products (or FDA-regulated products) is meant to include products, materials, ingredients, and other substances regulated by FDA, including drugs, biological products, medical devices, food substances (including food for animals), dietary supplements, cosmetic products, and tobacco products. 2

The guidance describes FDAs current thinking on determining whether FDA-regulated products involve the application of nanotechnology. This guidance is intended for manufacturers, suppliers, importers, and other stakeholders. (For convenience, the guidance will refer to these parties as industry.) FDAs guidance documents, including this guidance, do not establish legally enforceable responsibilities. Instead, guidance documents describe FDAs current thinking on a topic and should be viewed only as recommendations, unless specific regulatory or statutory requirements are cited. The use of the word should in Agency guidance documents means that something is suggested or recommended, but not required.

The application of nanotechnology may result in product attributes that differ from those of conventionally-manufactured products, and thus may merit particular examination. However, FDA (or we) does not categorically judge all products that involve the application of nanotechnology as intrinsically benign or harmful. FDA will regulate nanotechnology products under existing statutory authorities, in accordance with the specific legal standards applicable to each type of product under its jurisdiction. We consider the current framework for safety assessment sufficiently robust and flexible to be appropriate for a variety of materials, including nanomaterials. FDA maintains a product-focused, science-based regulatory policy. Technical assessments will be product-specific, taking into account the effects of nanomaterials in the particular biological and mechanical context of each product and its intended use. As such, the particular policies for each product area, both substantive and procedural, will vary according to the statutory authorities and relevant regulatory frameworks (Ref. 8). We believe that this regulatory policy allows for tailored approaches that adhere to applicable legal frameworks and reflect the characteristics of specific products or product classes and evolving technology and scientific understanding.

This guidance provides an overarching framework for FDAs approach to the regulation of nanotechnology products. It identifies two points to consider when determining whether the FDA-regulated product involves the application of nanotechnology. An affirmative finding to either of the Points to Consider, elaborated in section II below, might suggest the need for particular attention by the Agency and/or industry to the product to identify and address potential implications for safety, effectiveness, public health impact, or regulatory status of the product.

This guidance does not address, or presuppose, what ultimate regulatory outcome, if any, will result in a particular case where the use of these points may indicate that an FDA-regulated product involves the application of nanotechnology. Issues such as the safety, effectiveness, public health impact, or the regulatory status of nanotechnology products are currently addressed on a case-by-case basis using FDAs existing review processes. 3

This guidance also does not establish regulatory definitions. Rather, it is intended to help industry and others identify when they should consider potential implications for regulatory status, safety, effectiveness, or public health impact that may arise with the application of nanotechnology in FDA-regulated products. We advise industry to consult with FDA early in the development process to facilitate a mutual understanding of the specific scientific and regulatory issues for their nanotechnology products.

FDA will provide further guidance to industry, as needed, to address the application of nanotechnology as applicable to specific FDA-regulated products or classes of products (such as human foods, drugs, or cosmetics), consistent with existing federal policies (Refs. 9, 10). As appropriate, FDAs product-specific guidance documents will address issues such as the regulatory status, safety, effectiveness, performance, quality, or public health impact of nanotechnology products. 4

FDA has not established regulatory definitions of nanotechnology, nanomaterial, nanoscale, or other related terms. These terms are commonly used in relation to the engineering (i.e., deliberate manipulation, manufacture or selection) of materials that have at least one dimension in the size range of approximately 1 nanometers (nm) to 100 nm. For example, the National Nanotechnology Initiative Program defines nanotechnology as the understanding and control of matter at dimensions between approximately 1 and 100 nanometers, where unique phenomena enable novel applications (Ref. 11). Various published definitions mention other factors such as function, shape, charge, the ratio of surface area to volume, or other physical or chemical properties.

Based on our current scientific and technical understanding of nanomaterials and their characteristics, FDA believes that evaluations of safety, effectiveness, public health impact, or regulatory status of nanotechnology products should consider any unique properties and behaviors that the application of nanotechnology may impart. This guidance identifies two Points to Consider that should be used to evaluate whether FDA-regulated products involve the application of nanotechnology. These points address both particle dimensions and dimension-dependent properties or phenomena. Product-specific premarket review, when required, offers an opportunity for FDA to apply these points and, where products are not subject to premarket review, industry should consider these points. If either point applies to a given product, industry and FDA should consider whether the evaluations of safety, effectiveness, public health impact, or regulatory status of that product have identified and adequately addressed any unique properties or behaviors of the product.

These two Points to Consider are intended to provide an initial screening tool that can be broadly applied to all FDA-regulated products, with the understanding that these points are subject to change in the future as new information becomes available. In particular, FDA may further refine these points, either as applicable broadly to all FDA-regulated products or as applicable to particular products or classes of products, as justified by scientific information. This may include refining particle size parameters or introducing additional parameters such as those related to particle size distribution or specific properties. 5 We will consider future revisions to our approach, including developing regulatory definitions relevant to nanotechnology, as warranted and in keeping with evolving scientific understanding. As previously indicated, FDA also may provide additional guidance, including product-specific guidance documents, to address issues such as the regulatory status, safety, effectiveness, performance, quality, or public health impact of nanotechnology products.

At this time, when considering whether an FDA-regulated product involves the application of nanotechnology, FDA will ask:

1. Whether a material or end product is engineered to have at least one external dimension, or an internal or surface structure, in the nanoscale range (approximately 1 nm to 100 nm);

In addition, as we explain in more detail below, because materials or end products can also exhibit related properties or phenomena attributable to a dimension(s) outside the nanoscale range of approximately 1 nm to 100 nm that are relevant to evaluations of safety, effectiveness, performance, quality, public health impact, or regulatory status of products, we will also ask:

2. Whether a material or end product is engineered to exhibit properties or phenomena, including physical or chemical properties or biological effects, that are attributable to its dimension(s), even if these dimensions fall outside the nanoscale range, up to one micrometer (1,000 nm). 6

These considerations apply not only to new products, but also when changes to manufacturing processes alter the dimensions, properties, or effects of an FDA-regulated product or any of its constituent parts. 7

1. Material or end product that is engineered to have certain dimensions or exhibit certain properties (in Points 1 and 2)

The term engineered, used in both Points 1 and 2, is used to distinguish products that have been deliberately manipulated by the application of nanotechnology from those products that contain materials that naturally occur in the nanoscale range. FDA is particularly interested in the deliberate and purposeful manipulation and control of dimensions to produce specific properties, because the emergence of these new properties or phenomena may raise questions about the safety, effectiveness, performance, quality or public health impact that may warrant further evaluation. FDAs interest in materials or products engineered to have nanoscale dimensions or related dimension-dependent properties or phenomena is distinct from the more familiar use of biological or chemical substances that may naturally exist at small scales, including at the nanoscale, such as microorganisms or proteins.

The term engineered is also used to distinguish products that have been deliberately manipulated by the application of nanotechnology from products that may unintentionally include materials in the nanoscale range.

For example, the incidental presence of particles in the nanoscale range in conventionally-manufactured products 8 is not covered under the scope of this guidance. 9

2. Material or end product (in Points 1 and 2)

The phrase material or end product, referred to in both Points 1 and 2, is used to cover different types of articles that are regulated by FDA, such as products, materials, ingredients, and other substances regulated by FDA. This includes finished products (e.g., a drug tablet for administration to a patient) as well as materials that are intended for use in a finished product (e.g., a food additive added to a food during processing). In determining whether a material or end product satisfies either Point 1 or Point 2, FDA will examine the material or end product, and may also consider the constituent parts of the material or end product. Therefore, relevant considerations include whether a material or end product contains or involves in its manufacture the use of materials that meet either Point 1 or Point 2.

3. At least one external dimension, or an internal or surface structure, in the nanoscale range (approximately 1 nm to 100 nm) (in Point 1)

A size range of approximately 1 nm to 100 nm is commonly used in various working definitions or descriptions regarding nanotechnology proposed by the regulatory and scientific community. 10 In this size range, materials can exhibit new or altered physicochemical properties that can enable novel applications (Refs. 11, 13-15). Accordingly, per Point 1, if a material or end product is engineered to have at least one external dimension in the range of 1 nm to 100 nm, or is engineered to have an internal or surface structure in the range of 1 nm to 100 nm, industry and FDA should consider any unique characteristics or biological effects exhibited by the product that may influence its safety, effectiveness, public health impact, or regulatory status. Primary particles engineered with at least one external dimension within the nanoscale range are covered in Point 1. This Point also covers any aggregates or agglomerates formed by such nanoscale primary particles. In addition, coated, functionalized, or hierarchically-assembled engineered structures that include internal or surface discrete and functional nanoscale entities, such as where such entities are embedded or attached to the surface, are encompassed within Point 1. 11 Such engineered structures with discrete and functional nanoscale entities embedded or attached to the surface may have altered properties or phenomena that may affect product safety or effectiveness (Ref. 16). The inclusion of particles, objects, or structures with internal, surface, or external dimension(s) in the nanoscale range is consistent with approaches taken by other scientific and regulatory bodies (Refs. 17-23).

4. Properties or phenomena attributable to dimension(s) (in Point 2)

While size alone, for very small particles, is suggestive of the presence of properties meriting further examination, the identification and assessment of specific dimension-dependent properties and phenomena are ultimately more relevant for purposes of FDA regulatory review and oversight. Point 2, therefore, focuses on the properties of the material and its behavior in biological systems. 12 The phrase exhibits properties or phenomena that are attributable to its dimension(s), is used because properties and phenomena of materials in the nanoscale range enable applications that can affect the safety, effectiveness, performance, quality, public health impact, or regulatory status of FDA-regulated products. For example, as noted above, dimension-dependent properties or phenomena may be used for various functional effects such as increased bioavailability or decreased toxicity of drug products, better detection of pathogens, improved food packaging materials, or improved delivery of nutrients. These effects may derive from altered or unique characteristics of materials in the nanoscale range that are not normally observed or expected in larger-scale materials with the same chemical composition (Ref. 7). However, such changes may raise questions about the safety, effectiveness, performance, quality or public health impact of nanotechnology products. In addition, considerations such as routes of exposure, dosage, and behavior in various biological systems (including specific tissues and organs) (Refs. 13, 24) are critical for evaluating the safety, effectiveness, public health impact, or regulatory status of a wide array of products under FDAs jurisdiction. Such evaluations should include a consideration of the specific tests (whether traditional, modified, or new) that may be needed (Refs. 25, 26) to determine the physicochemical properties and biological effects of a product that involves the application of nanotechnology.

5. Dimension(s) of up to one micrometer (1,000 nm) (in Point 2)

Materials or end products can also exhibit properties or phenomena attributable to a dimension(s) outside the nanoscale range of approximately 1 nm to 100 nm. Physical and chemical properties and biological behavior that are relevant to evaluations of safety, effectiveness, performance, quality, public health impact, or regulatory status of products have been observed at dimensions outside the nanoscale range of approximately 1 nm to 100 nm (Refs. 27-30). Therefore, Point 2 focuses on the importance of considering properties or phenomena attributable to dimensions, even where such dimensions may be outside the nanoscale range of approximately 1 nm to 100 nm. FDAs consideration of materials with dimension(s) outside the nanoscale range of approximately 1 nm to 100 nm is consistent with approaches taken by other scientific and regulatory organizations. 13

At the present time, available scientific information does not establish a uniform upper boundary above 100 nm where novel properties and phenomena similar to those seen in materials with dimensions in the nanoscale range cease for all potential materials or end products. For this reason, at this time, FDA finds it reasonable to consider evaluation of materials or end products engineered to exhibit properties or phenomena attributable to dimensions up to 1,000 nm, as a means to screen materials for further examination and to determine whether these materials exhibit properties or phenomena attributable to their dimension(s) and associated with the application of nanotechnology. 14 An upper limit of one micrometer (1,000 nm) applied in the context of properties or phenomena attributable to dimensions serves both to: (1) include materials with dimension(s) outside the nanoscale range of approximately 1 nm to 100 nm that may exhibit dimension-dependent properties or phenomena associated with the application of nanotechnology and distinct from those of macro-scaled materials; and (2) exclude macro-scaled materials that may have properties attributable to their dimension(s) but are not likely associated with the application of nanotechnology.

An upper limit of 1,000 nm, combined with the presence of dimension-dependent properties or phenomena similar to those seen in materials with dimensions in the nanoscale range, provides an initial screening tool to help identify materials or products with properties or phenomena of particular relevance for regulatory review. The use of 1,000 nm as a reference point in this context should not be interpreted to mean that materials or products with dimensions above 1,000 nm cannot exhibit dimension-dependent properties or phenomena of importance to safety, effectiveness, public health impact, or regulatory status of the material or product. As noted above, we may further refine these Points to Consider, including this upper limit, either as applicable broadly to FDA-regulated products or as applicable to specific products or product categories.

The two Points to Consider elaborated in this guidance should be applied when considering whether an FDA-regulated product involves the application of nanotechnology. An affirmative finding to either of the Points to Consider, elaborated in this guidance, might suggest the need for particular attention to the product by FDA and/or industry for potential implications for safety, effectiveness, public health impact, or regulatory status of the product. We will consider future revisions to our approach, including developing regulatory definitions relevant to nanotechnology, as warranted and in keeping with evolving scientific understanding.

There remains a need to learn more about the potential role and importance of dimensions in the physical and chemical characteristics and biological effects exhibited by FDA-regulated products that involve the application of nanotechnology. 15 Product-specific premarket review, when required, offers an opportunity for FDA to better understand the properties and behavior of products that involve the application of nanotechnology. Where products that involve the application of nanotechnology are not subject to premarket review, we urge industry to consult with the Agency early in the product development process. In this way, any questions about the products regulatory status, safety, effectiveness, or public health impact can be appropriately and adequately addressed. FDA has and, as needed, will continue to provide additional guidance to industry in more targeted guidance documents to address these considerations.

We have placed these references on display in the Division of Dockets Management, Food and Drug Administration, 5630 Fishers Lane, rm. 1061, Rockville, MD 20852. You may see them at that location between 9 a.m. and 4 p.m., Monday through Friday. As of June 1, 2014, FDA had verified the Web site addresses for the references it makes available as hyperlinks from the Internet copy of this guidance, but FDA is not responsible for any subsequent changes to Non- FDA Web site references after June 1, 2014.

1. This guidance finalizes the draft guidance, entitled Draft Guidance for Industry: Considering Whether an FDA-Regulated Product Involves the Application of Nanotechnology, which was issued in June, 2011. This guidance was prepared by FDAs Office of Policy in the Office of the Commissioner, in consultation with FDAs Center for Biologics Evaluation and Research, Center for Drugs Evaluation and Research, Center for Devices and Radiological Health, Center for Food Safety and Applied Nutrition, Center for Tobacco Products, Center for Veterinary Medicine, National Center for Toxicological Research, Office of the Chief Scientist, Office of Foods and Veterinary Medicine, Office of Regulatory Affairs, Office of Special Medical Programs, and Nanotechnology Task Force.

2. Nanotechnology may also be applied to combination products (as defined at 21 CFR 3.2(e)).

3. It bears noting that the application of nanotechnology may also affect the classification of a product. For example, nanomaterials used in medical products may function through different modes of action than larger-scale materials with the same chemical composition, which may affect the classification of the product, for example as a drug or device.

4. FDAs guidance documents relevant to nanotechnology, including product-specific guidance documents that focus on nanotechnology applications in specific product sectors, can be found on the FDA's Nanotechnology webpage.

5. At this time, we do not have an adequate basis on which to determine a particle number threshold or a list of unique or novel properties that are applicable across the range of FDA-regulated products. In addition, challenges related to measurement methods and biological effects add further complexity to recommending use of particle number, weight, or surface area as the most appropriate units of measure. FDA intends to actively follow scientific developments on this issue and provide additional guidance, as appropriate.

6. As explained in section II.B.5. below, the use of 1,000 nm as a reference point should not be interpreted to mean that materials or products with dimensions above 1,000 nm cannot exhibit dimension-dependent properties or phenomena of importance to safety, effectiveness, public health impact, or regulatory status of the material or product. See further discussion on this issue in section II.B.5. below.

7. These Points to Consider are not intended to apply to products that have been previously reviewed or approved by FDA and where no changes are made to manufacturing processes that would alter the dimensions, properties or effects of the product or its constituent parts.

8. For example, small amounts of particles in the nanoscale range have been reported to be present in foods manufactured using conventional food manufacturing practices (Ref. 12).

9. However, evaluations of conventionally-manufactured products may include a consideration of the effects, if any, of such incidental presence of particles in the nanoscale range on the safety, effectiveness, or public health impact of a product.

10. For example, a size range of approximately 1 nm to 100 nm is used in definitions, working definitions, or descriptions published by the National Nanotechnology Initiative (Ref. 11); Environmental Protection Agency; European Commission (Ref. 17); Health Canada (Ref. 19); International Standards Organization (Ref. 20); Organization for Economic Cooperation and Developments Working Party on Nanotechnology and Working Party on Manufactured Nanomaterials ; National Cancer Institute; and American National Standards Institute (http://nanostandards.ansi.org/tiki-index.php).

11. This is not intended to include any incidental presence of internal or surface features with dimensions in the nanoscale range that may be present in conventionally-manufactured substances (for example, internal porosity, surface roughness or surface defects).

12. Consistent with Policy Principles for the U.S. Decision-Making Concerning Regulation and Oversight of Applications of Nanotechnology and Nanomaterials, Office of Science and Technology Policy, Office of Management and Budget, and Office of the United States Trade Representative, June 9, 2011 (Ref. 10).

13. For example, the Joint Research Centre and the Scientific Committee on Emerging and Newly Identified Health Risks of the European Commission concluded: In order to base a nanomaterials definition for regulatory purposes on size alone, the upper nanoscale limit should ideally be high enough to capture all types of materials that would need particular attention for regulation due to their nanoscale size. Upper limits which are often used in existing definitions, for example 100 nm, may require the introduction of one or more qualifiers based on structural features or properties other than size, in order to capture structures of concern (for example agglomerates or aggregates) with a size larger than 100 nm in the regulation (Ref. 22); The upper size limit for one or more external dimensions of 100 nm is complicated by the potential exclusion of aggregates, agglomerates and multicomponent assemblies that would have external sizes greater than this (Ref. 23); and An upper limit of 100 nm is commonly used by general consensus but there is no scientific evidence to support the appropriateness of this value (Stated as SCENIHR conclusions in the European Commission Recommendation on the definition of nanomaterial, Ref. 17). The European Commission further noted that it may be necessary to include additional materials, such as some materials with a size . . . greater than 100 nm in the scope of application of specific legislation or legislative provisions suited for a nanomaterial (Ref. 17). In addition, the International Organization for Standardization (ISO) acknowledged that health and safety considerations associated with intentionally produced and incidental nano-objects do not abruptly end at dimensions of 100 nm. As knowledge expands, it is abundantly clear that a robust terminology will need to capture and convey effectively the performance aspects of intentionally produced nano-objects and nanostructured materials in their definitions, apart from their fundamental size and shape (Ref. 20). More recently, Health Canada adopted a working definition of nanomaterial that, in part, reflects that it is possible for nanoscale properties/ phenomena to be exhibited outside the 1 nm to 100 nm size range, such as select quantum devices (Ref. 19). Finally, in its second regulatory review on nanomaterials, the European Commission noted that fullerenes, graphene flakes and single wall carbon nanotubes with one or more external dimensions below 1 nm should be considered as nanomaterials. Several types of nanomaterials were identified as not matching the EU definition, with an acknowledgment that there are an increasing number of particles which are engineered to have internal nanoscale features. Examples are core-shell particles and nano-encapsulates. These particles may be designed, for example for pharmaceutical applications, where the inner core particle is released in a certain environment. Some of these materials have an external diameter smaller than 100 nm, matching the EU nanomaterial definition, others have an external diameter larger than 100 nm, not matching the EU nanomaterial definition (Ref. 31).

14. However, as noted previously, FDA will consider further refinement of these Points to Consider for particular products or classes of products, as scientific information becomes available, including refining particle size parameters.

15. FDAs nanotechnology regulatory science program aims to further enhance FDAs scientific capabilities, including developing necessary data and tools to identify and measure dimension-dependent properties and assess their potential impact on safety or effectiveness. See 2013 Nanotechnology Regulatory Science Research Plan.

This guidance represents the Food and Drug Administrations (FDAs or the Agencys) current thinking on this topic. It does not create or confer any rights for or on any person and does not operate to bind FDA or the public. You can use an alternative approach if the approach satisfies the requirements of the applicable statutes and regulations. If you want to discuss an alternative approach, contact the FDA staff responsible for implementing this guidance. If you cannot identify the appropriate FDA staff, call the telephone number listed on the title page of this guidance.

You may submit electronic or written comments regarding this guidance at any time. Submit written comments on the guidance to the Division of Dockets Management (HFA-305), Food and Drug Administration, 5630 Fishers Lane, rm. 1061, Rockville, MD 20852. Submit electronic comments to http://www.regulations.gov. All comments should be identified with the docket number (FDA-2010-D-0530) listed in the notice of availability that publishes in the Federal Register.

Additional copies are available from: Office of Policy Office of the Commissioner Food and Drug Administration 10903 New Hampshire Avenue Silver Spring, MD 20993 Phone: 301-796-4830

For questions regarding this document contact: Office of the Commissioner Food and Drug Administration 10903 New Hampshire Avenue Silver Spring, MD 20993 301-796-4830.

U.S. Department of Health and Human Services Food and Drug Administration Office of the Commissioner

Continued here:
Considering Whether an FDA-Regulated Product Involves the ...

Nanotechnology, carbon nanotubeIllustration: Encyclopdia Britannica, Inc.; photographs:(microelectromechanical devices) Courtesy Sandia National Laboratories, SUMMiT Technologies; (quantum corral) courtesy IBM Research Center, unauthorized used not permitted; (red blood cells) Susumu Nishinaga/Science Source; (human hair) Manfred Kage/Peter Arnold, Inc.; (dust mite) Andrew Syred/Science Sourcethe manipulation and manufacture of materials and devices on the scale of atoms or small groups of atoms. The nanoscale is typically measured in nanometres, or billionths of a metre (nanos, the Greek word for dwarf, being the source of the prefix), and materials built at this scale often exhibit distinctive physical and chemical properties due to quantum mechanical effects. Although usable devices this small may be decades away (see microelectromechanical system), techniques for working at the nanoscale have become essential to electronic engineering, and nanoengineered materials have begun to appear in consumer products. For example, billions of microscopic nanowhiskers, each about 10 nanometres in length, have been molecularly hooked onto natural and synthetic fibres to impart stain resistance to clothing and other fabrics; zinc oxide nanocrystals have been used to create invisible sunscreens that block ultraviolet light; and silver nanocrystals have been embedded in bandages to kill bacteria and prevent infection.

Possibilities for the future are numerous. Nanotechnology may make it possible to manufacture lighter, stronger, and programmable materials that require less energy to produce than conventional materials, that produce less waste than with conventional manufacturing, and that promise greater fuel efficiency in land transportation, ships, aircraft, and space vehicles. Nanocoatings for both opaque and translucent surfaces may render them resistant to corrosion, scratches, and radiation. Nanoscale electronic, magnetic, and mechanical devices and systems with unprecedented levels of information processing may be fabricated, as may chemical, photochemical, and biological sensors for protection, health care, manufacturing, and the environment; new photoelectric materials that will enable the manufacture of cost-efficient solar-energy panels; and molecular-semiconductor hybrid devices that may become engines for the next revolution in the information age. The potential for improvements in health, safety, quality of life, and conservation of the environment are vast.

At the same time, significant challenges must be overcome for the benefits of nanotechnology to be realized. Scientists must learn how to manipulate and characterize individual atoms and small groups of atoms reliably. New and improved tools are needed to control the properties and structure of materials at the nanoscale; significant improvements in computer simulations of atomic and molecular structures are essential to the understanding of this realm. Next, new tools and approaches are needed for assembling atoms and molecules into nanoscale systems and for the further assembly of small systems into more-complex objects. Furthermore, nanotechnology products must provide not only improved performance but also lower cost. Finally, without integration of nanoscale objects with systems at the micro- and macroscale (that is, from millionths of a metre up to the millimetre scale), it will be very difficult to exploit many of the unique properties found at the nanoscale.

play_circle_outlinenanotechnology; pharmacology University of Melbourne, Victoria, Australia (A Britannica Publishing Partner)Nanotechnology is highly interdisciplinary, involving physics, chemistry, biology, materials science, and the full range of the engineering disciplines. The word nanotechnology is widely used as shorthand to refer to both the science and the technology of this emerging field. Narrowly defined, nanoscience concerns a basic understanding of physical, chemical, and biological properties on atomic and near-atomic scales. Nanotechnology, narrowly defined, employs controlled manipulation of these properties to create materials and functional systems with unique capabilities.

In contrast to recent engineering efforts, nature developed nanotechnologies over billions of years, employing enzymes and catalysts to organize with exquisite precision different kinds of atoms and molecules into complex microscopic structures that make life possible. These natural products are built with great efficiency and have impressive capabilities, such as the power to harvest solar energy, to convert minerals and water into living cells, to store and process massive amounts of data using large arrays of nerve cells, and to replicate perfectly billions of bits of information stored in molecules of deoxyribonucleic acid (DNA).

There are two principal reasons for qualitative differences in material behaviour at the nanoscale (traditionally defined as less than 100 nanometres). First, quantum mechanical effects come into play at very small dimensions and lead to new physics and chemistry. Second, a defining feature at the nanoscale is the very large surface-to-volume ratio of these structures. This means that no atom is very far from a surface or interface, and the behaviour of atoms at these higher-energy sites have a significant influence on the properties of the material. For example, the reactivity of a metal catalyst particle generally increases appreciably as its size is reducedmacroscopic gold is chemically inert, whereas at nanoscales gold becomes extremely reactive and catalytic and even melts at a lower temperature. Thus, at nanoscale dimensions material properties depend on and change with size, as well as composition and structure.

Using the processes of nanotechnology, basic industrial production may veer dramatically from the course followed by steel plants and chemical factories of the past. Raw materials will come from the atoms of abundant elementscarbon, hydrogen, and siliconand these will be manipulated into precise configurations to create nanostructured materials that exhibit exactly the right properties for each particular application. For example, carbon atoms can be bonded together in a number of different geometries to create variously a fibre, a tube, a molecular coating, or a wire, all with the superior strength-to-weight ratio of another carbon materialdiamond. Additionally, such material processing need not require smokestacks, power-hungry industrial machinery, or intensive human labour. Instead, it may be accomplished either by growing new structures through some combination of chemical catalysts and synthetic enzymes or by building them through new techniques based on patterning and self-assembly of nanoscale materials into useful predetermined designs. Nanotechnology ultimately may allow people to fabricate almost any type of material or product allowable under the laws of physics and chemistry. While such possibilities seem remote, even approaching natures virtuosity in energy-efficient fabrication would be revolutionary.

Even more revolutionary would be the fabrication of nanoscale machines and devices for incorporation into micro- and macroscale systems. Once again, nature has led the way with the fabrication of both linear and rotary molecular motors. These biological machines carry out such tasks as muscle contraction (in organisms ranging from clams to humans) and shuttling little packets of material around within cells while being powered by the recyclable, energy-efficient fuel adenosine triphosphate. Scientists are only beginning to develop the tools to fabricate functioning systems at such small scales, with most advances based on electronic or magnetic information processing and storage systems. The energy-efficient, reconfigurable, and self-repairing aspects of biological systems are just becoming understood.

The potential impact of nanotechnology processes, machines, and products is expected to be far-reaching, affecting nearly every conceivable information technology, energy source, agricultural product, medical device, pharmaceutical, and material used in manufacturing. Meanwhile, the dimensions of electronic circuits on semiconductors continue to shrink, with minimum feature sizes now reaching the nanorealm, under 100 nanometres. Likewise, magnetic memory materials, which form the basis of hard disk drives, have achieved dramatically greater memory density as a result of nanoscale structuring to exploit new magnetic effects at nanodimensions. These latter two areas represent another major trend, the evolution of critical elements of microtechnology into the realm of nanotechnology to enhance performance. They are immense markets driven by the rapid advance of information technology.

play_circle_outlineFeynman, Richard P.; quantum electrodynamics; nanotechnologyCourtesy of Northwestern University (A Britannica Publishing Partner)In a lecture in 1959 to the American Physical Society, Theres Plenty of Room at the Bottom, American Nobelist Richard P. Feynman presented his audience with a vision of what could be done with extreme miniaturization. He began his lecture by noting that the Lords Prayer had been written on the head of a pin and asked,

Why cannot we write the entire 24 volumes of the Encyclopdia Britannica on the head of a pin? Lets see what would be involved. The head of a pin is a sixteenth of an inch across. If you magnify it by 25,000 diameters, the area of the head of the pin is then equal to the area of all the pages of the Encyclopdia Britannica. Therefore, all it is necessary to do is to reduce in size all the writing in the Encyclopdia by 25,000 times. Is that possible? The resolving power of the eye is about 1/120 of an inchthat is roughly the diameter of one of the little dots on the fine half-tone reproductions in the Encyclopdia. This, when you demagnify it by 25,000 times, is still 80 angstroms in diameter32 atoms across, in an ordinary metal. In other words, one of those dots still would contain in its area 1,000 atoms. So, each dot can easily be adjusted in size as required by the photoengraving, and there is no question that there is enough room on the head of a pin to put all of the Encyclopdia Britannica.

Feynman was intrigued by biology and pointed out that

cells are very tiny, but they are very active; they manufacture various substances; they walk around; they wiggle; and they do all kinds of marvelous thingsall on a very small scale. Also, they store information. Consider the possibility that we too can make a thing very small which does what we wantthat we can manufacture an object that maneuvers at that level!

He also considered using big tools to make smaller tools that could make yet smaller tools, eventually obtaining nanoscale tools for directly manipulating atoms and molecules. In considering what all this might mean, Feynman declared,

I can hardly doubt that when we have some control of the arrangement of things on a small scale we will get an enormously greater range of possible properties that substances can have, and of different things that we can do.

Perhaps the biggest barrier to following these prophetic thoughts was simply the immediate lack of tools to manipulate and visualize matter at such a small scale. The availability of tools has always been an enabling aspect of the advance of all science and technology, and some of the key tools for nanotechnology are discussed in the next section, Pioneers.

Starting with a 1981 paper in the Proceedings of the National Academy of Sciences and following with two popular books, Engines of Creation (1986) and Nanosystems (1992), American scientist K. Eric Drexler became one of the foremost advocates of nanotechnology. In fact, Drexler was the first person anywhere to receive a Ph.D. in molecular nanotechnology (from the Massachusetts Institute of Technology). In his written works he takes a molecular view of the world and envisions molecular machines doing much of the work of the future. For example, he refers to assemblers, which will manipulate individual atoms to manufacture structures, and replicators, which will be able to make multiple copies of themselves in order to save time dealing with the billions of atoms needed to make objects of useful size. In an article for Encyclopdia Britannicas 1990 Yearbook of Science and the Future, Drexler wrote:

Cells and tissues in the human body are built and maintained by molecular machinery, but sometimes that machinery proves inadequate: viruses multiply, cancer cells spread, or systems age and deteriorate. As one might expect, new molecular machines and computers of subcellular size could support the bodys own mechanisms. Devices containing nanocomputers interfaced to molecular sensors and effectors could serve as an augmented immune system, searching out and destroying viruses and cancer cells. Similar devices programmed as repair machines could enter living cells to edit out viral DNA sequences and repair molecular damage. Such machines would bring surgical control to the molecular level, opening broad new horizons in medicine.

Drexlers futurist visions have stimulated much thought, but the assembler approach has failed to account for the strong influence of atomic and molecular forces (i.e., the chemistry) at such dimensions. The controversy surrounding these popularizations, and the potential dangers of entities such as intelligent replicators (however remote), have stimulated debate over the ethical and societal implications of nanotechnology.

A number of key technological milestones have been achieved by working pioneers. Molecular beam epitaxy, invented by Alfred Cho and John Arthur at Bell Labs in 1968 and developed in the 1970s, enabled the controlled deposition of single atomic layers. This tool provided for nanostructuring in one dimension as atomic layers were grown one upon the next. It subsequently became important in the area of compound semiconductor device fabrication. For example, sandwiching one-nanometre-thick layers of nonmagnetic-sensor materials between magnetic layers in computer disk drives resulted in large increases in storage capacity, and a similar use of nanostructuring resulted in more energy-efficient semiconductor lasers for use in compact disc players.

In 1981 Gerd Binnig and Heinrich Rohrer developed the scanning tunneling microscope at IBMs laboratories in Switzerland. This tool provided a revolutionary advance by enabling scientists to image the position of individual atoms on surfaces. It earned Binnig and Rohrer a Nobel Prize in 1986 and spawned a wide variety of scanning probe tools for nanoscale observations.

The observation of new carbon structures marked another important milestone in the advance of nanotechnology, with Nobel Prizes for the discoverers. In 1985 Robert F. Curl, Jr., Harold W. Kroto, and Richard E. Smalley discovered the first fullerene, the third known form of pure carbon (after diamond and graphite). They named their discovery buckminsterfullerene (buckyball) for its resemblance to the geodesic domes promoted by the American architect R. Buckminster Fuller. Technically called C60 for the 60 carbon atoms that form their hollow spherical structure, buckyballs resemble a football one nanometre in diameter (see figure). In 1991 Sumio Iijima of NEC Corporation in Japan discovered carbon nanotubes, in which the carbon ringlike structures are extended from spheres into long tubes of varying diameter. Taken together, these new structures surprised and excited the imaginations of scientists about the possibilities of forming well-defined nanostructures with unexpected new properties.

The scanning tunneling microscope not only allowed for the imaging of atoms by scanning a sharp probe tip over a surface, but it also allowed atoms to be pushed around on the surface. With a slight bias voltage applied to the probe tip, certain atoms could be made to adhere to the tip used for imaging and then to be released from it. Thus, in 1990 Donald Eigler spelled out the letters of his companys logo, IBM, by moving 35 xenon atoms into place on a nickel surface. This demonstration caught the publics attention because it showed the precision of the emerging nanoscale tools.

At nanoscale dimensions the properties of materials no longer depend solely on composition and structure in the usual sense. Nanomaterials display new phenomena associated with quantized effects and with the preponderance of surfaces and interfaces.

Quantized effects arise in the nanometre regime because the overall dimensions of objects are comparable to the characteristic wavelength for fundamental excitations in materials. For example, electron wave functions (see also de Broglie wave) in semiconductors are typically on the order of 10 to 100 nanometres. Such excitations include the wavelength of electrons, photons, phonons, and magnons, to name a few. These excitations carry the quanta of energy through materials and thus determine the dynamics of their propagation and transformation from one form to another. When the size of structures is comparable to the quanta themselves, it influences how these excitations move through and interact in the material. Small structures may limit flow, create wave interference effects, and otherwise bring into play quantum mechanical selection rules not apparent at larger dimensions.

Quantum mechanical properties for confinement of electrons in one dimension have long been exploited in solid-state electronics. Semiconductor devices are grown with thin layers of differing composition so that electrons (or holes in the case of missing electron charges) can be confined in specific regions of the structure (known as quantum wells). Thin layers with larger energy bandgaps can serve as barriers that restrict the flow of charges to certain conditions under which they can tunnel through these barriersthe basis of resonant tunneling diodes. Superlattices are periodic structures of repeating wells that set up a new set of selection rules which affect the conditions for charges to flow through the structure. Superlattices have been exploited in cascade lasers to achieve far infrared wavelengths. Modern telecommunications is based on semiconductor lasers that exploit the unique properties of quantum wells to achieve specific wavelengths and high efficiency.

The propagation of photons is altered dramatically when the size and periodicity of the transient structure approach the wavelength of visible light (400 to 800 nanometres). When photons propagate through a periodically varying dielectric constantfor example, semiconductor posts surrounded by airquantum mechanical rules define and limit the propagation of the photons depending on their energy (wavelength). This new behaviour is analogous to the quantum mechanical rules that define the motion of electrons through crystals, giving bandgaps for semiconductors. In one dimension, compound semiconductor superlattices can be grown epitaxially with the alternating layers having different dielectric constants, thus providing highly reflective mirrors for specific wavelengths as determined by the repeat distance of layers in the superlattice. These structures are used to provide built-in mirrors for vertical-cavity surface-emitting lasers, which are used in communications applications. In two and three dimensions, periodic structures known as photonic crystals offer additional control over photon propagation.

Photonic crystals are being explored in a variety of materials and periodicities, such as two-dimensional hexagonal arrays of posts fabricated in compound semiconductors or stacked loglike arrays of silicon bars in three dimensions. The dimensions of these structures depend on the wavelength of light being propagated and are typically in the range of a few hundred nanometres for wavelengths in the visible and near infrared. Photonic crystal properties based on nanostructured materials offer the possibility of confining, steering, and separating light by wavelength on unprecedented small scales and of creating new devices such as lasers that require very low currents to initiate lasing (called near-thresholdless lasers). These structures are being extensively investigated as the tools for nanostructuring materials are steadily advancing. Researchers are particularly interested in the infrared wavelengths, where dimensional control is not as stringent as at the shorter visible wavelengths and where optical communications and chemical sensing provide motivation for potential new applications.

Nanoscale materials also have size-dependent magnetic behaviour, mechanical properties, and chemical reactivity. At very small sizes (a few nanometres), magnetic nanoclusters have a single magnetic domain, and the strongly coupled magnetic spins on each atom combine to produce a particle with a single giant spin. For example, the giant spin of a ferromagnetic iron particle rotates freely at room temperature for diameters below about 16 nanometres, an effect termed superparamagnetism. Mechanical properties of nanostructured materials can reach exceptional strengths. As a specific example, the introduction of two-nanometre aluminum oxide precipitates into thin films of pure nickel results in yield strengths increasing from 0.15 to 5 gigapascals, which is more than twice that for a hard bearing steel. Another example of exceptional mechanical properties at the nanoscale is the carbon nanotube, which exhibits great strength and stiffness along its longitudinal axis.

The preponderance of surfaces is a major reason for the change in behaviour of materials at the nanoscale. Since up to half of all the atoms in nanoparticles are surface atoms, properties such as electrical transport are no longer determined by solid-state bulk phenomena. Likewise, the atoms in nanostructures have a higher average energy than atoms in larger structures, because of the large proportion of surface atoms. For example, catalytic materials have a greater chemical activity per atom of exposed surface as the catalyst is reduced in size at the nanoscale. Defects and impurities may be attracted to surfaces and interfaces, and interactions between particles at these small dimensions can depend on the structure and nature of chemical bonding at the surface. Molecular monolayers may be used to change or control surface properties and to mediate the interaction between nanoparticles.

Surfaces and their interactions with molecular structures are basic to all biology. The intersection of nanotechnology and biotechnology offers the possibility of achieving new functions and properties with nanostructured surfaces. In this surface- and interface-dominated regime, biology does an exquisite job of selectively controlling functions through a combination of structure and chemical forces. The transcription of information stored in genes and the selectivity of biochemical reactions based on chemical recognition of complex molecules are examples where interfaces play the key role in establishing nanoscale behaviour. Atomic forces and chemical bonds dominate at these dimensions, while macroscopic effectssuch as convection, turbulence, and momentum (inertial forces)are of little consequence.

As discussed in the section Properties at the nanoscale, material propertieselectrical, optical, magnetic, mechanical, and chemicaldepend on their exact dimensions. This opens the way for development of new and improved materials through manipulation of their nanostructure. Hierarchical assemblies of nanoscale-engineered materials into larger structures, or their incorporation into devices, provide the basis for tailoring radically new materials and machines.

Natures assemblies point the way to improving structural materials. The often-cited abalone seashell provides a beautiful example of how the combination of a hard, brittle inorganic material with nanoscale structuring and a soft, tough organic material can produce a strong, durable nanocompositebasically, these nanocomposites are made of calcium carbonate bricks held together by a glycoprotein glue. New engineered materials are emergingsuch as polymer-clay nanocompositesthat are not only strong and tough but also lightweight and easier to recycle than conventional reinforced plastics. Such improvements in structural materials are particularly important for the transportation industry, where reduced weight directly translates into improved fuel economy. Other improvements can increase safety or decrease the impact on the environment of fabrication and recycling. Further advances, such as truly smart materials that signal their impending failure or are even able to self-repair flaws, may be possible with composites of the future.

Sensors are central to almost all modern control systems. For example, multiple sensors are used in automobiles for such diverse tasks as engine management, emission control, security, safety, comfort, vehicle monitoring, and diagnostics. While such traditional applications for physical sensing generally rely on microscale sensing devices, the advent of nanoscale materials and structures has led to new electronic, photonic, and magnetic nanosensors, sometimes known as smart dust. Because of their small size, nanosensors exhibit unprecedented speed and sensitivity, extending in some cases down to the detection of single molecules. For example, nanowires made of carbon nanotubes, silicon, or other semiconductor materials exhibit exceptional sensitivity to chemical species or biological agents. Electrical current through nanowires can be altered by having molecules attached to their surface that locally perturb their electronic band structure. By means of nanowire surfaces coated with sensor molecules that selectively attach particular species, charge-induced changes in current can be used to detect the presence of those species. This same strategy is adopted for many classes of sensing systems. New types of sensors with ultrahigh sensitivity and specificity will have many applications; for example, sensors that can detect cancerous tumours when they consist of only a few cells would be a very significant advance.

Nanomaterials also make excellent filters for trapping heavy metals and other pollutants from industrial wastewater. One of the greatest potential impacts of nanotechnology on the lives of the majority of people on Earth will be in the area of economical water desalination and purification. Nanomaterials will very likely find important use in fuel cells, bioconversion for energy, bioprocessing of food products, waste remediation, and pollution-control systems.

A recent concern regarding nanoparticles is whether their small sizes and novel properties may pose significant health or environmental risks. In general, ultrafine particlessuch as the carbon in photocopier toners or in soot produced by combustion engines and factorieshave adverse respiratory and cardiovascular effects on people and animals. Studies are under way to determine if specific nanoscale particles pose higher risks that may require special regulatory restrictions. Of particular concern are potential carcinogenic risks from inhaled particles and the possibility for very small nanoparticles to cross the blood-brain barrier to unknown effect. Nanomaterials currently receiving attention from health officials include carbon nanotubes, buckyballs, and cadmium selenide quantum dots. Studies of the absorption through the skin of titanium oxide nanoparticles (used in sunscreens) are also planned. More far-ranging studies of the toxicity, transport, and overall fate of nanoparticles in ecosystems and the environment have not yet been undertaken. Some early animal studies, involving the introduction of very high levels of nanoparticles which resulted in the rapid death of many of the subjects, are quite controversial.

Nanotechnology promises to impact medical treatment in multiple ways. First, advances in nanoscale particle design and fabrication provide new options for drug delivery and drug therapies. More than half of the new drugs developed each year are not water-soluble, which makes their delivery difficult. In the form of nanosized particles, however, these drugs are more readily transported to their destination, and they can be delivered in the conventional form of pills.

More important, nanotechnology may enable drugs to be delivered to precisely the right location in the body and to release drug doses on a predetermined schedule for optimal treatment. The general approach is to attach the drug to a nanosized carrier that will release the medicine in the body over an extended period of time or when specifically triggered to do so. In addition, the surfaces of these nanoscale carriers may be treated to seek out and become localized at a disease sitefor example, attaching to cancerous tumours. One type of molecule of special interest for these applications is an organic dendrimer. A dendrimer is a special class of polymeric molecule that weaves in and out from a hollow central region. These spherical fuzz balls are about the size of a typical protein but cannot unfold like proteins. Interest in dendrimers derives from the ability to tailor their cavity sizes and chemical properties to hold different therapeutic agents. Researchers hope to design different dendrimers that can swell and release their drug on exposure to specifically recognized molecules that indicate a disease target. This same general approach to nanoparticle-directed drug delivery is being explored for other types of nanoparticles as well.

Another approach involves gold-coated nanoshells whose size can be adjusted to absorb light energy at different wavelengths. In particular, infrared light will pass through several centimetres of body tissue, allowing a delicate and precise heating of such capsules in order to release the therapeutic substance within. Furthermore, antibodies may be attached to the outer gold surface of the shells to cause them to bind specifically to certain tumour cells, thereby reducing the damage to surrounding healthy cells.

A second area of intense study in nanomedicine is that of developing new diagnostic tools. Motivation for this work ranges from fundamental biomedical research at the level of single genes or cells to point-of-care applications for health delivery services. With advances in molecular biology, much diagnostic work now focuses on detecting specific biological signatures. These analyses are referred to as bioassays. Examples include studies to determine which genes are active in response to a particular disease or drug therapy. A general approach involves attaching fluorescing dye molecules to the target biomolecules in order to reveal their concentration.

Another approach to bioassays uses semiconductor nanoparticles, such as cadmium selenide, which emit light of a specific wavelength depending on their size. Different-size particles can be tagged to different receptors so that a wider variety of distinct colour tags are available than can be distinguished for dye molecules. The degradation in fluorescence with repeated excitation for dyes is avoided. Furthermore, various-size particles can be encapsulated in latex beads and their resulting wavelengths read like a bar code. This approach, while still in the exploratory stage, would allow for an enormous number of distinct labels for bioassays.

Another nanotechnology variation on bioassays is to attach one half of the single-stranded complementary DNA segment for the genetic sequence to be detected to one set of gold particles and the other half to a second set of gold particles. When the material of interest is present in a solution, the two attachments cause the gold balls to agglomerate, providing a large change in optical properties that can be seen in the colour of the solution. If both halves of the sequence do not match, no agglomeration will occur and no change will be observed.

Approaches that do not involve optical detection techniques are also being explored with nanoparticles. For example, magnetic nanoparticles can be attached to antibodies that in turn recognize and attach to specific biomolecules. The magnetic particles then act as tags and handlebars through which magnetic fields can be used for mixing, extracting, or identifying the attached biomolecules within microlitre- or nanolitre-sized samples. For example, magnetic nanoparticles stay magnetized as a single domain for a significant period, which enables them to be aligned and detected in a magnetic field. In particular, attached antibodymagnetic-nanoparticle combinations rotate slowly and give a distinctive magnetic signal. In contrast, magnetically tagged antibodies that are not attached to the biological material being detected rotate more rapidly and so do not give the same distinctive signal.

play_circle_outlinematerials science; wrinkle formation Massachusetts Institute of Technology (A Britannica Publishing Partner)Microfluidic systems, or labs-on-chips, have been developed for biochemical assays of minuscule samples. Typically cramming numerous electronic and mechanical components into a portable unit no larger than a credit card, they are especially useful for conducting rapid analysis in the field. While these microfluidic systems primarily operate at the microscale (that is, millionths of a metre), nanotechnology has contributed new concepts and will likely play an increasing role in the future. For example, separation of DNA is sensitive to entropic effects, such as the entropy required to unfold DNA of a given length. A new approach to separating DNA could take advantage of its passage through a nanoscale array of posts or channels such that DNA molecules of different lengths would uncoil at different rates.

Other researchers have focused on detecting signal changes as nanometre-wide DNA strands are threaded through a nanoscale pore. Early studies used pores punched in membranes by viruses; artificially fabricated nanopores are also being tested. By applying an electric potential across the membrane in a liquid cell to pull the DNA through, changes in ion current can be measured as different repeating base units of the molecule pass through the pores. Nanotechnology-enabled advances in the entire area of bioassays will clearly impact health care in many ways, from early detection, rapid clinical analysis, and home monitoring to new understanding of molecular biology and genetic-based treatments for fighting disease.

Another biomedical application of nanotechnology involves assistive devices for people who have lost or lack certain natural capabilities. For example, researchers hope to design retinal implants for vision-impaired individuals. The concept is to implant chips with photodetector arrays to transmit signals from the retina to the brain via the optic nerve. Meaningful spatial information, even if only at a rudimentary level, would be of great assistance to the blind. Such research illustrates the tremendous challenge of designing hybrid systems that work at the interface between inorganic devices and biological systems.

Closely related research involves implanting nanoscale neural probes in brain tissue to activate and control motor functions. This requires effective and stable wiring of many electrodes to neurons. It is exciting because of the possibility of recovery of control for motor-impaired individuals. Studies employing neural stimulation of damaged spinal cords by electrical signals have demonstrated the return of some locomotion. Researchers are also seeking ways to assist in the regeneration and healing of bone, skin, and cartilagefor example, developing synthetic biocompatible or biodegradable structures with nanosized voids that would serve as templates for regenerating specific tissue while delivering chemicals to assist in the repair process. At a more sophisticated level, researchers hope to someday build nanoscale or microscale machines that can repair, assist, or replace more-complex organs.

Semiconductor experts agree that the ongoing shrinkage in conventional electronic devices will inevitably reach fundamental limits due to quantum effects such as tunneling, in which electrons jump out of their prescribed circuit path and create atomic-scale interference between devices. At that point, radical new approaches to data storage and information processing will be required for further advances. For example, radically new systems have been imagined that are based on quantum computing or biomolecular computing.

The use of molecules for electronic devices was suggested by Mark Ratner of Northwestern University and Avi Aviram of IBM as early as the 1970s, but proper nanotechnology tools did not become available until the turn of the 21st century. Wiring up molecules some half a nanometre wide and a few nanometres long remains a major challenge, and an understanding of electrical transport through single molecules is only beginning to emerge. A number of groups have been able to demonstrate molecular switches, for example, that could conceivably be used in computer memory or logic arrays. Current areas of research include mechanisms to guide the selection of molecules, architectures for assembling molecules into nanoscale gates, and three-terminal molecules for transistor-like behaviour. More-radical approaches include DNA computing, where single-stranded DNA on a silicon chip would encode all possible variable values and complementary strand interactions would be used for a parallel processing approach to finding solutions. An area related to molecular electronics is that of organic thin-film transistors and light emitters, which promise new applications such as video displays that can be rolled out like wallpaper and flexible electronic newspapers.

Carbon nanotubes have remarkable electronic, mechanical, and chemical properties. Depending on their specific diameter and the bonding arrangement of their carbon atoms, nanotubes exhibit either metallic or semiconducting behaviour. Electrical conduction within a perfect nanotube is ballistic (negligible scattering), with low thermal dissipation. As a result, a wire made from a nanotube, or a nanowire, can carry much more current than an ordinary metal wire of comparable size. At 1.4 nanometres in diameter, nanotubes are about a hundred times smaller than the gate width of silicon semiconductor devices. In addition to nanowires for conduction, transistors, diodes, and simple logic circuits have been demonstrated by combining metallic and semiconductor carbon nanotubes. Similarly, silicon nanowires have been used to build experimental devices, such as field-effect transistors, bipolar transistors, inverters, light-emitting diodes, sensors, and even simple memory. A major challenge for nanowire circuits, as for molecular electronics, is connecting and integrating these devices into a workable high-density architecture. Ideally, the structure would be grown and assembled in place. Crossbar architectures that combine the function of wires and devices are of particular interest.

At nanoscale dimensions the energy required to add one additional electron to a small island (isolated physical region)for example, through a tunneling barrierbecomes significant. This change in energy provides the basis for devising single-electron transistors. At low temperatures, where thermal fluctuations are small, various single-electron-device nanostructures are readily achievable, and extensive research has been carried out for structures with confined electron flow. However, room-temperature applications will require that sizes be reduced significantly, to the one-nanometre range, to achieve stable operation. For large-scale application with millions of devices, as found in current integrated circuits, the need for structures with very uniform size to maintain uniform device characteristics presents a significant challenge. Also, in this and many new nanodevices being explored, the lack of gain is a serious drawback limiting implementation in large-scale electronic circuits.

Spintronics refers to electronic devices that perform logic operations based on not just the electrical charge of carriers but also their spin. For example, information could be transported or stored through the spin-up or spin-down states of electrons. This is a new area of research, and issues include the injection of spin-polarized carriers, their transport, and their detection. The role of nanoscale structure and electronic properties of the ferromagnetic-semiconductor interface on the spin injection process, the growth of new ferromagnetic semiconductors with nanoscale control, and the possible use of nanostructured features to manipulate spin are all of interest.

Current approaches to information storage and retrieval include high-density, high-speed, solid-state electronic memories, as well as slower (but generally more spacious) magnetic and optical discs (see computer memory). As the minimum feature size for electronic processing approaches 100 nanometres, nanotechnology provides ways to decrease further the bit size of the stored information, thus increasing density and reducing interconnection distances for obtaining still-higher speeds. For example, the basis of the current generation of magnetic disks is the giant magnetoresistance effect. A magnetic read/write head stores bits of information by setting the direction of the magnetic field in nanometre-thick metallic layers that alternate between ferromagnetic and nonferromagnetic. Differences in spin-dependent scattering of electrons at the interface layers lead to resistance differences that can be read by the magnetic head. Mechanical properties, particularly tribology (friction and wear of moving surfaces), also play an important role in magnetic hard disk drives, since magnetic heads float only about 10 nanometres above spinning magnetic disks.

Another approach to information storage that is dependent on designing nanometre-thick magnetic layers is under commercial development. Known as magnetic random access memory (MRAM), a line of electrically switchable magnetic material is separated from a permanently magnetized layer by a nanoscale nonmagnetic interlayer. A resistance change that depends on the relative alignment of the fields is read electrically from a large array of wires through cross lines. MRAM will require a relatively small evolution from conventional semiconductor manufacturing, and it has the added benefit of producing nonvolatile memory (no power or batteries are needed to maintain stored memory states).

Still at an exploratory stage, studies of electrical conduction through molecules have generated interest in their possible use as memory. While still very speculative, molecular and nanowire approaches to memory are intriguing because of the small volume in which the bits of memory are stored and the effectiveness with which biological systems store large amounts of information.

Nanoscale structuring of optical devices, such as vertical-cavity surface-emitting lasers (VCSELs), quantum dot lasers, and photonic crystal materials, is leading to additional advances in communications technology.

VCSELs have nanoscale layers of compound semiconductors epitaxially grown into their structurealternating dielectric layers as mirrors and quantum wells. Quantum wells allow the charge carriers to be confined in well-defined regions and provide the energy conversion into light at desired wavelengths. They are placed in the lasers cavity to confine carriers at the nodes of a standing wave and to tailor the band structure for more efficient radiative recombination. One-dimensional nanotechnology techniques involving precise growth of very thin epitaxial semiconductor layers were developed during the 1990s. Such nanostructuring has enhanced the efficiency of VCSELs and reduced the current required for lasing to start (called the threshold current). Because of improving performance and their compatibility with planar manufacturing technology, VCSELs are fast becoming a preferred laser source in a variety of communications applications.

More recently, the introduction of quantum dots (regions so small that they can be given a single electric charge) into semiconductor lasers has been investigated and found to give additional benefitsboth further reductions in threshold current and narrower line widths. Quantum dots further confine the optical emission modes within a very narrow spectrum and give the lowest threshold current densities for lasing achieved to date in VCSELs. The quantum dots are introduced into the laser during the growth of strained layers, by a process called Stransky-Krastanov growth. They arise because of the lattice mismatch stress and surface tension of the growing film. Improvements in ways to control precisely the resulting quantum dots to a more uniform single size are still being sought.

Photonic crystals provide a new means to control the steering and manipulation of photons based on periodic dielectric lattices with repeat dimensions on the order of the wavelength of light. These materials can have very exotic properties, such as not allowing light within certain wavelengths to be propagated in a material based on the particular periodic structure. Photonic lattices can act as perfect wavelength-selective mirrors to reflect back incident light from all orientations. They provide the basis for optical switching, steering, and wavelength separation on unprecedented small scales. The periodic structures required for these artificial crystals can be configured as both two- and three-dimensional lattices. Optical sources, switches, and routers are being considered, with two-dimensional planar geometries receiving the most attention, because of their greater ease of fabrication.

Another potentially important communications application for nanotechnology is microelectromechanical systems (MEMS), devices sized at the micrometre level (millionths of a metre). MEMS are currently poised to have a major impact on communications via optical switching. In the future, electromechanical devices may shrink to nanodimensions to take advantage of the higher frequencies of mechanical vibration at smaller masses. The natural (resonant) frequency of vibration for small mechanical beams increases as their size decreases, so that little power is needed to drive them as oscillators. Their efficiency is rated by a quality factor, known as Q, which is a ratio of the energy stored per cycle versus the energy dissipated per cycle. The higher the Q, the more precise the absolute frequency of an oscillator. The Q is very high for micro- and nanoscale mechanical oscillators, and these devices can reach very high frequencies (up to microwave frequencies), making them potential low-power replacements for electronic-based oscillators and filters.

Mechanical oscillators have been made from silicon at dimensions of 10 100 nanometres, where more than 10 percent of the atoms are less than one atomic distance from the surface. While highly homogeneous materials can be made at these dimensionsfor example, single-crystal silicon barssurfaces play an increasing role at nanoscales, and energy losses increase, presumably because of surface defects and molecular species absorbed on surfaces.

It is possible to envision even higher frequencies, in what might be viewed as the ultimate in nanomechanical systems, by moving from nanomachined structures to molecular systems. As an example, multiwalled carbon nanotubes are being explored for their mechanical properties. When the ends of the outer nanotube are removed, the inner tube may be pulled partway out from the outer tube where van der Waals forces between the two tubes will supply a restoring force. The inner tube can thus oscillate, sliding back and forth inside the outer tube. The resonant frequency of oscillation for such structures is predicted to be above one gigahertz (one billion cycles per second). It is unknown whether connecting such systems to the macro world and protecting them from surface effects will ever be practical.

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Home > Nanotechnology Introduction

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Introduction - Descriptive introduction to nanotechnology.

Basics - Technical and measurement basics.

FAQ - Frequently Asked Questions.

Current Uses - A short list of areas where we see nanoscale science being applied today.

Possible Futures and Predictions.

Nano This and Nano That - A short list of "nano-named things."

Glossary - The most comprehensive glossary of nanotechnology terms.

Articles - Papers by some of today's leading minds.

Nanotubes & Buckyballs - Nanotubes and Buckyballs described, with images and links.

Ethics of Nanotechnology - Some of the ethics inherent in the changes nanotechnology will bring.

Who's Who in Nanotechnology - A short list of some of the early champions and discoverers.

Disruptive Technology - History is full of examples of disruptive technologies; nanotechnology is poised to be the next.

Metric Prefix Table.

All that men want from any new technology is the efficiency that they can rely on and Panasonic wet and dry shaver with nano technology is certainly a good example..

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Nanotechnology Introduction Pages

Nanotechnology Basics: For Students and Other Learners

What is nanotechnology all about?

Nanotechnology is the engineering of tiny machines the projected ability to build things from the bottom up inside personal nanofactories (PNs), using techniques and tools being developed today to make complete, highly advanced products. Ultimately, nanotechnology will enable control of matter at the nanometer scale, using mechanochemistry. Shortly after this envisioned molecular machinery is created, it will result in a manufacturing revolution, probably causing severe disruption. It also has serious economic, social, environmental, and military implications.

A nanometer is one billionth of a meter, roughly the width of three or four atoms. The average human hair is about 25,000 nanometers wide.

You can see a longer explanation here. And to check out more of those tiny machines, click here.

What's a personal nanofactory?

It's a proposed new appliance, something that might sit on a countertop in your home. To build a personal nanofactory (PN), you need to start with a working fabricator, a nanoscale device that can combine individual molecules into useful shapes. A fabricator could build a very small nanofactory, which then could build another one twice as big, and so on. Within a period of weeks, you have a tabletop model.

Click to enlarge Artwork by John Burch, Lizard Fire Studios (3D Animation, Game Development)

Products made by a PN will be assembled from nanoblocks, which will be fabricated within the nanofactory. Computer aided design (CAD) programs will make it possible to create state-of-the-art products simply by specifying a pattern of predesigned nanoblocks. The question of when we will see a flood of nano-built products boils down to the question of how quickly the first fabricator can be designed and built.

MOVIE TIME: A short film called Productive Nanosystems: from Molecules to Superproducts depicts an animated view of a nanofactory and demonstrates key steps in the sample process that converts basic molecules into a billion-CPU laptop computer. The 4-minute streaming video is online here.

What could nanofactories produce?

How does 'mechanochemistry' work?

It's a bit like enzymes (if you know your chemistry): you fix onto a molecule or two, then twist or pull or push in a precise way until a chemical reaction happens right where you want it. This happens in a vacuum, so you don't have water molecules bumping around. It's a lot more controllable that way.

So, if you want to add an atom to a surface, you start with that atom bound to a molecule called a "tool tip" at the end of a mechanical manipulator. You move the atom to the point where you want it to end up. You move the atom next to the surface, and make sure that it has a weaker bond to the tool tip than to the surface. When you bring them close enough, the bond will transfer. This is ordinary chemistry: an atom moving from one molecule to another when they come close enough to each other, and when the movement is energetically favorable. What's different about mechanochemistry is that the tool tip molecule can be positioned by direct computer control, so you can do this one reaction at a wide variety of sites on the surface. Just a few reactions give you a lot of flexibility in what you make.

MECHANOSYNTHETIC REACTIONS Based on quantum chemistry by Walch and Merkle [Nanotechnology, 9, 285 (1998)], to deposit carbon, a device moves a vinylidenecarbene along a barrier-free path to bond to a diamond (100) surface dimer, twists 90 to break a pi bond, and then pulls to cleave the remaining sigma bond.

Why do some scientists dismiss this stuff as science fiction?

The whole concept of advanced nanotechnology molecular manufacturing (MM) is so complex and unfamiliar, and so staggering in its implications, that a few scientists, engineers, and other pundits have flatly declared it to be impossible. The debate is further confused by science-fictional hype and media misconceptions.

It should be noted that none of those who dismiss MM are experts in the field. They may work in chemistry, biotechnology, or other nanoscale sciences or technologies, but are not sufficiently familiar with MM theory to critique it meaningfully.

Many of the objections, including those of the late Richard Smalley, do not address the actual published proposals for MM. The rest are unfounded and incorrect assertions, contradicted by detailed calculations based on the relevant physical laws.

Is nanotechnology bad or good?

Nanotechnology offers great potential for benefit to humankind, and also brings severe dangers. While it is appropriate to examine carefully the risks and possible toxicity of nanoparticles and other products of nanoscale technology, the greatest hazards are posed by malicious or unwise use of molecular manufacturing. CRN's focus is on designing and promoting mechanisms for safe development and effective administration of MM.

If MM is so dangerous, why not just completely ban all research and development?

Viewed with pessimism, molecular manufacturing could appear far too risky to be allowed to develop to anywhere near its full potential. However, a naive approach to limiting R&D, such as relinquishment, is flawed for at least two reasons. First, it will almost certainly be impossible to prevent the development of MM somewhere in the world. China, Japan, and other Asian nations have thriving nanotechnology programs, and the rapid advance of enabling technologies such as biotechnology, MEMS, and scanning-probe microscopy ensures that R&D efforts will be far easier in the near future than they are today. Second, MM will provide benefits that are simply too good to pass up, including environmental repair; clean, cheap, and efficient manufacturing; medical breakthroughs; immensely powerful computers; and easier access to space.

What about "grey goo"?

The dangers of self-replicating nanobots the so-called grey goo have been widely discussed, and it is generally perceived that molecular manufacturing is uncomfortably close to grey goo. However, the proposed production system that CRN supports does not involve free-floating assemblers or nanobots, but much larger factories with all the nanoscale machinery fastened down and inert without external control. As far as we know, a self-replicating mechanochemical nanobot is not excluded by the laws of physics, but such a thing would be extremely difficult to design and build even with a full molecular manufacturing capability. Fiction like Michael Crichton's Prey might be good entertainment, but it's not very good science.

How soon will molecular manufacturing be developed?

Based on our studies, CRN believes that molecular manufacturing could be successfully developed within the next ten years, and almost certainly will be developed within twenty years. For more, see our Timeline page.

Shouldn't we be working on current problems like poverty, pollution, and stopping terrorism, instead of putting money into these far future technologies?

We should do both! Development and application of molecular manufacturing clearly can have a positive impact on solving many of today's most urgent problems. But it's equally clear than MM can exacerbate many of society's ills. Knowing that it may be developed within the next decade or two (which is not "far future"), makes preparation for MM an urgent priority.

More! More! More!

Nanotechnology: Get REAL! - An online PowerPoint presentation

Nano Simulation - A way to visualize what is meant by molecular manufacturing

Nanotechnology on an Upward Slope - An online PowerPoint presentation

CRN's Responsible Nanotechnology Blog - Stay up to date every day

Must-See Nanofactory Movie - Four minutes of fantastic future tech

CRN-talk - Join the conversation!

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Nanotechnology Basics for Students

Nanobots working in artery, human bloodstream. Digital artistic rendition. Fredrik Skol/Getty Images

By Andrew Zimmerman Jones

Updated January 31, 2016.

Nanotechnology is the understanding and control of matter at the realm of 1 to 100 nanometers. (For reference, a piece of paper is about 100,000 nanometers thick.) At the nanoscale, matter functions differently from both the individual atomic and macroscopic scales, so some unique properties are available for use in the field.

Nanotechnology is a natural end-result of scientific development and our ability to understand and manipulate matter at smaller and smaller levels. Just as computers have gone from bulky, room-filling monstrosities to handheld computers, such reductions in size will continue until we reach fundamental physical limits.

On December 29, 1959, the influential American physicist Richard P. Feynman presented a talk to the American Physical Society entitled "There's Plenty of Room at the Bottom: An Invitation to Enter a New Field of Physics." Among physicists, this is respectfully called "the classic talk" (it's the first hit on a Google search of "classic talk").

He asked "Why cannot we write the entire 24 volumes of the Encyclopedia Brittanica on the head of a pin?" and introduced the concept of nanotechnology.

Though Feynman's speech inspired many researchers, it wasn't until the mid-1980s that nanotechnology began to seep into the cultural mainstream conversation. In 1986, the MIT researcher K. Eric Drexler wrote Engines of Creation which laid out extensive prospects of emerging nanotechnology research.

One major application of nanotechnology is in the field of medicine, and in fact the knowledge gained from research of natural nanomachines, such as bacteria, has proven essential to the field. In this respect, it has developed some close connections with biophysics. It is theorized that man-made nanomachines could repair damage to the human body that is currently untreatable.

One material which is frequently discussed in nanotechnological research is graphene, an atom-thick form of graphite which was discovered by a University of Manchester team in 2004. The discovery of graphene was recognized with the awarding of the 2010 Nobel Prize in Physics toAndre Geim and Konstantin Novoselov.

There are few degrees of study specifically in nanotechnology, so look for a good, well-rounded physics program. Nanotechnology works at tiny levels of matter, so knowledge of atomic, molecular, chemical and quantum physics is essential to this field of study. Working knowledge of biochemistry, chemistry, and biophysics, as well as a proficiency with complex mathematics, would also help qualify you for this field.

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Nanotechnology - About.com Education

A word of caution

Definition of nan'otechnol'ogy n

Human hair fragment and a network of single-walled carbon nanotubes (Image: Jirka Cech)

It seems that a size limitation of nanotechnology to the 1-100 nm range, the area where size-dependant quantum effects come to bear, would exclude numerous materials and devices, especially in the pharamaceutical area, and some experts caution against a rigid definition based on a sub-100 nm size.

Another important criteria for the definition is the requirement that the nano-structure is man-made. Otherwise you would have to include every naturally formed biomolecule and material particle, in effect redefining much of chemistry and molecular biology as 'nanotechnology.'

The most important requirement for the nanotechnology definition is that the nano-structure has special properties that are exclusively due to its nanoscale proportions.

The U.S. National Nantechnology Initiatve (NNI) provides the following definition:

Nanotechnology is the understanding and control of matter at dimensions between approximately 1 and 100 nanometers, where unique phenomena enable novel applications. Encompassing nanoscale science, engineering, and technology, nanotechnology involves imaging, measuring, modeling, and manipulating matter at this length scale.

A nanometer is one-billionth of a meter. A sheet of paper is about 100,000 nanometers thick; a single gold atom is about a third of a nanometer in diameter. Dimensions between approximately 1 and 100 nanometers are known as the nanoscale. Unusual physical, chemical, and biological properties can emerge in materials at the nanoscale. These properties may differ in important ways from the properties of bulk materials and single atoms or molecules.

The design, characterization, production, and application of structures, devices, and systems by controlled manipulation of size and shape at the nanometer scale (atomic, molecular, and macromolecular scale) that produces structures, devices, and systems with at least one novel/superior characteristic or property.

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Nanotechnology Introduction - What is nanotechnology?

Scientists demonstrate first color-tunable and first graphene-based LED

(Phys.org)Currently, all light-emitting diodes (LEDs) emit light of only one color, which is predefined during fabrication. So far, tuning the color of light produced by a single LED has never been realized, despite numerous ...

(Phys.org)A team of researchers with members from Stanford University and several institutions in China is claiming to have found a way to create a sample of stanenea one-atom thick mesh (buckled honeycomb) of tin that ...

Chemists have found a new, more efficient method to perform light-driven reactions, opening up another possible pathway to harness sunlight for energy. The journal Science is publishing the new method, which is based on plasmon ...

(Phys.org)Advancements in surface-enhanced Raman spectroscopy using a scanning tunneling microscope under ultrahigh vacuum and low temperature have allowed a group of researchers from The University of Science and Technology ...

(Phys.org)Scientists have proposed a new family of structures that are three-dimensional (3D) variations of graphene, the simplest example of which is called a "hyper-honeycomb." If the proposed structures can be experimentally ...

(Phys.org)Researchers have designed and implemented an algorithm that solves computing problems using a strategy inspired by the way that an amoeba branches out to obtain resources. The new algorithm, called AmoebaSAT, ...

(Phys.org)Nanoscale motors, like their macroscale counterparts, can be built to run on a variety of chemical fuels, such as hydrogen peroxide and others. But unlike macroscale motors, some nanomotors can also run without ...

(Phys.org)A new semiliquid battery developed by researchers at The University of Texas at Austin has exhibited encouraging early results, encompassing many of the features desired in a state-of-the-art energy-storage device. ...

The art of kirigami involves cutting paper into intricate designs, like snowflakes. Cornell physicists are kirigami artists, too, but their paper is only an atom thick, and could become some of the smallest machines the world ...

Researchers have developed an ultrafast light-emitting device that can flip on and off 90 billion times a second and could form the basis of optical computing.

(Phys.org)Researchers have proposed a new type of artificial neuron called a "straintronic spin neuron" that could serve as the basic unit of artificial neural networkssystems modeled on human brains that have the ability ...

A team of researchers from Berkeley Lab and Columbia University has passed a major milestone in molecular electronics with the creation of the world's highest-performance single-molecule diode. Working at Berkeley Lab's Molecular ...

Carbon nanomaterials display extraordinary physical properties, outstanding among any other substance available, and graphene has grown as the most promising material for brand-new electronic circuitry, sensors and optical ...

(Phys.org)Currently, up to 75% of the energy generated by a car's engine is lost as waste heat. In theory, some of this waste heat can be converted into electricity using thermoelectric devices, although so far the efficiency ...

If you want to form very flexible chains of nanoparticles in liquid in order to build tiny robots with flexible joints or make magnetically self-healing gels, you need to revert to childhood and think about sandcastles.

One big problem faced by electrodes in rechargeable batteries, as they go through repeated cycles of charging and discharging, is that they must expand and shrink during each cyclesometimes doubling in volume, and then ...

Serendipity has as much a place in science as in love. That's what Northeastern physicists Swastik Kar and Srinivas Sridhar found during their four-year project to modify graphene, a stronger-than-steel infinitesimally thin ...

Australian researchers funded by the National Heart Foundation are a step closer to a safer and more effective way to treat heart attack and stroke via nanotechnology.

(Phys.org)Despite the many great achievements of computers, no man-made computer can learn from its environment, adapt to its surroundings, spontaneously self-organize, and solve complex problems that require these abilities ...

Scientists have been making nanoparticles for more than two decades in two-dimensional sheets, three-dimensional crystals and random clusters. But they have never been able to get a sheet of nanoparticles to curve or fold ...

The ability to control the time-resolved optical responses of hybrid plasmonic nanostructures was demonstrated by a team led by scientists in the Nanophotonics Group at the Center for Nanoscale Materials including collaborators ...

Ferroelectric materials have applications in next-generation electronics devices from optoelectronic modulators and random access memory to piezoelectric transducers and tunnel junctions. Now researchers at Tokyo Institute ...

It's a notion that might be pulled from the pages of science-fiction novel - electronic devices that can be injected directly into the brain, or other body parts, and treat everything from neurodegenerative disorders to paralysis.

Graphene has been called a wonder material, capable of performing great and unusual material acrobatics. Boron nitride nanotubes are no slackers in the materials realm either, and can be engineered for physical and biological ...

The world's newest and brightest synchrotron light sourcethe National Synchrotron Light Source II (NSLS-II) at the U.S. Department of Energy's Brookhaven National Laboratoryhas produced one of the first publications ...

Led by Young Duck Kim, a postdoctoral research scientist in James Hone's group at Columbia Engineering, a team of scientists from Columbia, Seoul National University (SNU), and Korea Research Institute of Standards and Science ...

It's snack time: you have a plain oatmeal cookie, and a pile of chocolate chips. Both are delicious on their own, but if you can find a way to combine them smoothly, you get the best of both worlds.

When a duck paddles across a pond or a supersonic plane flies through the sky, it leaves a wake in its path. Wakes occur whenever something is traveling through a medium faster than the waves it createsin the duck's case ...

Today's computer chips pack billions of tiny transistors onto a plate of silicon within the width of a fingernail. Each transistor, just tens of nanometers wide, acts as a switch that, in concert with others, carries out ...

Three-dimensional structures of boron nitride might be the right stuff to keep small electronics cool, according to scientists at Rice University.

Swarms of microscopic, magnetic, robotic beads could be scrubbing in next to the world's top vascular surgeonsall taking aim at blocked arteries. These microrobots, which look and move like corkscrew-shaped bacteria, are ...

Nanofiberspolymer filaments only a couple of hundred nanometers in diameterhave a huge range of potential applications, from solar cells to water filtration to fuel cells. But so far, their high cost of manufacture ...

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As scientists continue to hunt for a material that will make it possible to pack more transistors on a chip, new research from McGill University and Universit de Montral adds to evidence that black phosphorus could emerge ...

Most of the world's electricity-producing power plantswhether powered by coal, natural gas, or nuclear fissionmake electricity by generating steam that turns a turbine. That steam then is condensed back to water, and ...

(Phys.org)Is it possible to engineer self-replicating nanomaterials? It could be if we borrow nature's building blocks. DNA is a self-replicating molecule where its component parts, nucleotides, have specific chemical ...

The electrodes for connections on the "sunny side" of a solar cell need to be not just electrically conductive, but transparent as well. As a result, electrodes are currently made either by using thin strips of silver in ...

Instruments that measure the properties of light, known as spectrometers, are widely used in physical, chemical, and biological research. These devices are usually too large to be portable, but MIT scientists have now shown ...

(Phys.org)When exposed to air, a luminescent 2D material called molybdenum telluride (MoTe2) appears to decompose within a couple days, losing its optical contrast and becoming virtually transparent. But when scientists ...

(Phys.org)There are many different ways to generate a hologram, each with its own advantages and disadvantages. Trying to maximize the advantages, researchers in a new study have designed a hologram made of a metamaterial ...

A group of University of Wisconsin-Madison engineers and a collaborator from China have developed a nanogenerator that harvests energy from a car's rolling tire friction.

Graphene has been called the miracle material but the single-atomic layer material is still seeking its place in the materials world. Now a method to make 'defective' graphene could provide the answer.

A team of IBM researchers in Zurich, Switzerland with support from colleagues in Yorktown Heights, New York has developed a relatively simple, robust and versatile process for growing crystals made from compound semiconductor ...

A growing interest in thermoelectric materialswhich convert waste heat to electricityand pressure to improve heat transfer from increasingly powerful microelectronic devices have led to improved theoretical and experimental ...

Millimetre-sized crystals of high-quality graphene can be made in minutes instead of hours using a new scalable technique, Oxford University researchers have demonstrated.

The global rise in antibiotic resistance is a growing threat to public health, damaging our ability to fight deadly infections such as tuberculosis.

Researchers have developed a new method for growing 'hybrid' crystals at the nanoscale, in which quantum dots essentially nanoscale semiconductors of different materials can be sequentially incorporated into a host ...

Under the direction of Latha Venkataraman, associate professor of applied physics at Columbia Engineering, researchers have designed a new technique to create a single-molecule diode, and, in doing so, they have developed ...

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Nanotechnology News - Phys.org

Aug. 14, 2015 Researchers used their Campanile nano-optical probe to make some surprising discoveries about molybdenum disulfide, a member of the transition metal dichalcogenides (TMDCs) semiconductor ... read more Aug. 14, 2015 Using a method they invented for joining disparate elemental layers into a stable material with uniform, predictable properties, researchers are testing an array of new combinations that may vastly ... read more Aug. 14, 2015 Researchers have developed a model system for so-called soft colloids. The model gives us a better understanding of correlations between the atomic structure of colloids and their perceptible ... read more Aug. 13, 2015 An unusual magnetic effect has been discovered in nanolayers of an oxide of lanthanum and manganese (LaMnO3). The research revealed an abrupt magnetic transition brought about by the slightest change ... read more Sediment Dwelling Creatures at Risk from Nanoparticles in Common Household Products Aug. 13, 2015 Biologists highlight the risks posed to aquatic organisms when nanoparticles 'transform' on contact with water and as they pass from water to sediment and then into sediment dwelling ... read more Attosecond Electron Catapult Aug. 12, 2015 A team of physicists and chemists has studied the interaction of light with tiny glass particles. The relationship between strong laser pulses and glass nanoparticles is a special one -- one that ... read more Aug. 11, 2015 Scientists devised a new way of assembling ordered crystals made of nanoparticles. In this process, nanoparticles in the shape of cubes, octahedrons, and spheres coordinate with each other to build ... read more Aug. 11, 2015 Scientists have developed a new technique for finding quantum dots. A quantum dot should produce one and only one photon -- the smallest constituent of light -- each time it is energized, and this ... read more Aug. 10, 2015 Scientists have created a solid-state memory technology that allows for high-density storage with a minimum of ... read more Aug. 10, 2015 A new microscope will allow scientists studying biological and synthetic materials to simultaneously observe chemical and physical properties on and beneath the ... read more Nanotech Wound Healing in Diabetes Aug. 10, 2015 People with diabetes mellitus often suffer from impaired wound healing. Now, scientists have developed antibacterial nanofibres of cellulose acetate loaded with silver that could be used in a new ... read more Aug. 10, 2015 An emerging technique called fluctuation X-ray scattering (FXS) could provide much more detail about a proteins molecular structure than traditional solution scattering. But a major limitation for ... read more Aug. 7, 2015 A new method to extract more efficient and polarized light from quantum dots (QDs) over a large-scale area has been developed by researchers. Their method, which combines QD and photonic crystal ... read more Aug. 7, 2015 The chemical reactions that make methanol from carbon dioxide rely on a catalyst to speed up the conversion, and scientists identified a new material that could fill this role. With its unique ... read more Aug. 7, 2015 Molybdenum ditelluride (MoTe2) is a crystalline compound that if pure enough can be used as a transistor. Its molecular structure is an atomic sandwich made up of one molybdenum atom for every ... read more Aug. 7, 2015 There are no magic bullets for global energy needs. But fuel cells in which electrical energy is harnessed directly from live, self-sustaining chemical reactions promise cheaper alternatives to ... read more Aug. 6, 2015 Chemists have discovered an unexpected way to use plasmonic metal, harvesting the high energy electrons excited by light in plasmon and then using this energy to do chemistry. Plasmon is a collective ... read more Aug. 6, 2015 Easily manufactured, low cost, lightweight, flexible dielectric polymers that can operate at high temperatures may be the solution to energy storage and power conversion in electric vehicles and ... read more Aug. 6, 2015 An international team of physicists has used carbon nanotubes to enhance the efficiency of laser-driven particle acceleration. This significant advance brings compact sources of ionizing radiation ... read more Aug. 5, 2015 Researchers show that magnetic nanoparticles encased in oily liquid shells can bind together in water, much like sand particles mixed with the right amount of water can form ... read more

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Nanotechnology News -- ScienceDaily

"Nanobots" redirects here. For the They Might Be Giants album, see Nanobots (album).

Nanorobotics is the emerging technology field creating machines or robots whose components are at or close to the scale of a nanometre (109 meters).[1][2][3] More specifically, nanorobotics refers to the nanotechnology engineering discipline of designing and building nanorobots, with devices ranging in size from 0.110 micrometers and constructed of nanoscale or molecular components.[4][5] The names nanobots, nanoids, nanites, nanomachines, or nanomites have also been used to describe these devices currently under research and development.[6][7]

Nanomachines are largely in the research and development phase,[8] but some primitive molecular machines and nanomotors have been tested. An example is a sensor having a switch approximately 1.5 nanometers across, capable of counting specific molecules in a chemical sample. The first useful applications of nanomachines might be in nanomedicine. For example,[9]biological machines could be used to identify and destroy cancer cells.[10][11] Another potential application is the detection of toxic chemicals, and the measurement of their concentrations, in the environment. Rice University has demonstrated a single-molecule car developed by a chemical process and including buckyballs for wheels. It is actuated by controlling the environmental temperature and by positioning a scanning tunneling microscope tip.

Another definition is a robot that allows precision interactions with nanoscale objects, or can manipulate with nanoscale resolution. Such devices are more related to microscopy or scanning probe microscopy, instead of the description of nanorobots as molecular machine. Following the microscopy definition even a large apparatus such as an atomic force microscope can be considered a nanorobotic instrument when configured to perform nanomanipulation. For this perspective, macroscale robots or microrobots that can move with nanoscale precision can also be considered nanorobots.

According to Richard Feynman, it was his former graduate student and collaborator Albert Hibbs who originally suggested to him (circa 1959) the idea of a medical use for Feynman's theoretical micromachines (see nanotechnology). Hibbs suggested that certain repair machines might one day be reduced in size to the point that it would, in theory, be possible to (as Feynman put it) "swallow the doctor". The idea was incorporated into Feynman's 1959 essay There's Plenty of Room at the Bottom.[12]

Since nanorobots would be microscopic in size, it would probably be necessary for very large numbers of them to work together to perform microscopic and macroscopic tasks. These nanorobot swarms, both those incapable of replication (as in utility fog) and those capable of unconstrained replication in the natural environment (as in grey goo and its less common variants[clarification needed]), are found in many science fiction stories, such as the Borg nanoprobes in Star Trek and The Outer Limits episode The New Breed.

Some proponents of nanorobotics, in reaction to the grey goo scenarios that they earlier helped to propagate, hold the view that nanorobots capable of replication outside of a restricted factory environment do not form a necessary part of a purported productive nanotechnology, and that the process of self-replication, if it were ever to be developed, could be made inherently safe. They further assert that their current plans for developing and using molecular manufacturing do not in fact include free-foraging replicators.[13][14]

The most detailed theoretical discussion of nanorobotics, including specific design issues such as sensing, power communication, navigation, manipulation, locomotion, and onboard computation, has been presented in the medical context of nanomedicine by Robert Freitas. Some of these discussions remain at the level of unbuildable generality and do not approach the level of detailed engineering.

The joint use of nanoelectronics, photolithography, and new biomaterials provides a possible approach to manufacturing nanorobots for common medical applications, such as for surgical instrumentation, diagnosis and drug delivery.[15][16][17] This method for manufacturing on nanotechnology scale is currently in use in the electronics industry.[18] So, practical nanorobots should be integrated as nanoelectronics devices, which will allow tele-operation and advanced capabilities for medical instrumentation.[19][20]

Nubot is an abbreviation for "nucleic acid robot." Nubots are organic molecular machines at the nanoscale.[21] DNA structure can provide means to assemble 2D and 3D nanomechanical devices. DNA based machines can be activated using small molecules, proteins and other molecules of DNA.[22][23][24] Biological circuit gates based on DNA materials have been engineered as molecular machines to allow in-vitro drug delivery for targeted health problems.[25] Such material based systems would work most closely to smart biomaterial drug system delivery,[26] while not allowing precise in vivo teleoperation of such engineered prototypes.

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Just give me the FAQ

Manufactured products are made from atoms. The properties of those products depend on how those atoms are arranged.

If we rearrange the atoms in coal we can make diamond.

If we rearrange the atoms in sand (and add a few other trace elements) we can make computer chips.

If we rearrange the atoms in dirt, water and air we can make potatoes.

Todays manufacturing methods are very crude at the molecular level. Casting, grinding, milling and even lithography move atoms in great thundering statistical herds. It's like trying to make things out of LEGO blocks with boxing gloves on your hands. Yes, you can push the LEGO blocks into great heaps and pile them up, but you can't really snap them together the way you'd like.

In the future, nanotechnology (more specifically, molecular nanotechnology or MNT) will let us take off the boxing gloves. We'll be able to snap together the fundamental building blocks of nature easily, inexpensively and in most of the ways permitted by the laws of nature. This will let us continue the revolution in computer hardware to its ultimate limits: molecular computers made from molecular logic gates connected by molecular wires. This new pollution free manufacturing technology will also let us inexpensively fabricate a cornucopia of new products that are remarkably light, strong, smart, and durable.

"Nanotechnology" has become something of a buzzword and is applied to many products and technologies that are often largely unrelated to molecular nanotechnology. While these broader usages encompass many valuable evolutionary improvements of existing technology, molecular nanotechnology will open up qualitatively new and exponentially expanding opportunities on a historically unprecedented scale. We will use the word "nanotechnology" to mean "molecular nanotechnology".

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Self-cleaning nano coating - nanotechnology in Canadian news
News spot done by The Canadian Press in 2009 about Nanotechnology. Green Earth Nano Science shows its Gens Nano SolarStucco self-cleaning coatings. Visit website for more: ...

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Korean govt to invest $165 million on nanotechnology sector this year
Korea is pushing to take the lead in the growing nanotechnology market. With a goal of taking up 20 percent of the global market share by the year 2020... the government says it will spend...

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DOWNLOAD PDF Introduction to Nanotechnology FREE
Introduction to Nanotechnology by Charles P. Poole Jr. Frank J. Owens DOWNLOAD LINK: http://bit.ly/1OeHLir This self-confessed introduction provides technical administrators and managers...

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[UNOFFICIAL] Presentation: Advanced Materials and Nanotechnology, Silpakorn University - version I
[UNOFFICIAL]VDO Presentation: Advanced Materials and Nanotechnology, Faculty of Engineering and Industrial Technology, Silpakorn University ...

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What is nanotechnology science experiments for kids Dr Michelle Dickinson radio interview
Radio interview for NewsTalkZB, Dr Michelle Dickinson introduces nanotechnology and her passion for sharing her excitement of science by building a lava lamp out of kitchen ingredients. Initially...

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What is nanotechnology & science experiments for kids Dr Michelle Dickinson radio interview - Video