Consumer goods

Nanotechnology is already impacting the field of consumer goods, providing products with novel functions ranging from easy-to-clean to scratch-resistant. Modern textiles are wrinkle-resistant and stain-repellent; in the mid-term clothes will become “smart”, through embedded “wearable electronics”. Already in use are different nanoparticle improved products. Especially in the field of cosmetics, such novel products have a promising potential.

Foods

Complex set of engineering and scientific challenges in the food and bioprocessing industry for manufacturing high quality and safe food through efficient and sustainable means can be solved through nanotechnology. Bacteria identification and food quality monitoring using biosensors; intelligent, active, and smart food packaging systems; nanoencapsulation of bioactive food compounds are few examples of emerging applications of nanotechnology for the food industry. Nanotechnology can be applied in the production, processing, safety and packaging of food. A nanocomposite coating process could improve food packaging by placing anti-microbial agents directly on the surface of the coated film. Nanocomposites could increase or decrease gas permeability of different fillers as is needed for different products. They can also improve the mechanical and heat-resistance properties and lower the oxygen transmission rate. Research is being performed to apply nanotechnology to the detection of chemical and biological substances for sensanges in foods.

Nano-foods

New consumer products Emerging Nanotechnologies (PEN), based on an inventory it has drawn up of 609 known or claimed nano-products.

On PEN's list are three foods -- a brand of canola cooking oil called Canola Active Oil, a tea called Nanotea and a chocolate diet shake called Nanoceuticals Slim Shake Chocolate.

According to company information posted on PEN's Web site, the canola oil, by Shemen Industries of Israel, contains an additive called "nanodrops" designed to carry vitamins, minerals and phytochemicals through the digestive system.and urea

The shake, according to U.S. manufacturer RBC Life Sciences Inc., uses cocoa infused "NanoClusters" to enhance the taste and health benefits of cocoa without the need for extra sugar.

Household

The most prominent application of nanotechnology in the household is self-cleaning or “easy-to-clean” surfaces on ceramics or glasses. Nanoceramic particles have improved the smoothness and heat resistance of common household equipment such as the flat iron.

Optics

The first sunglasses using protective and anti-reflective ultrathin polymer coatings are on the market. For optics, nanotechnology also offers scratch resistant surface coatings based on nanocomposites. Nano-optics could allow for an increase in precision of pupil repair and other types of laser eye surgery.

Textiles

The use of engineered nanofibers already makes clothes water- and stain-repellent or wrinkle-free. Textiles with a nanotechnological finish can be washed less frequently and at lower temperatures. Nanotechnology has been used to integrate tiny carbon particles membrane and guarantee full-surface protection from electrostatic charges for the wearer. Many other applications have been developed by research institutions such as the Textiles Nanotechnology Laboratory at Cornell University

Cosmetics

One field of application is in sunscreens. The traditional chemical UV protection approach suffers from its poor long-term stability. A sunscreen based on mineral nanoparticles such as titanium dioxide offer several advantages. Titanium oxide nanoparticles have a comparable UV protection property as the bulk material, but lose the cosmetically undesirable whitening as the particle size is decreased.

Agriculture

Applications of nanotechnology have the potential to change the entire agriculture sector and food industry chain from production to conservation, processing, packaging, transportation, and even waste treatment. NanoScience concepts and Nanotechnology applications have the potential to redesign the production cycle, restructure the processing and conservation processes and redefine the food habits of the people.

Heavy Industry use of nanotechnology

An inevitable use of nanotechnology will be in heavy industry.

Aerospace

Lighter and stronger materials will be of immense use to aircraft manufacturers, leading to increased performance. Spacecraft will also benefit, where weight is a major factor. Nanotechnology would help to reduce the size of equipment and thereby decrease fuel-consumption required to get it airborne.

Hang gliders may be able to halve their weight while increasing their strength and toughness through the use of nanotech materials. Nanotech is lowering the mass of supercapacitors that will increasingly be used to give power to assistive electrical motors for launching hang gliders off flatland to thermal-chasing altitudes.

Construction

Nanotechnology has the potential to make construction faster, cheaper, safer, and more varied. Automation of nanotechnology construction can allow for the creation of structures from advanced homes to massive skyscrapers much more quickly and at much lower cost.

Refineries

Using nanotech applications, refineries producing materials such as steel and aluminium will be able to remove any impurities in the materials they create.

Vehicle manufacturers

Much like aerospace, lighter and stronger materials will be useful for creating vehicles that are both faster and safer. Combustion engines will also benefit from parts that are more hard-wearing and more heat-resistant.

Antibody-Nanoparticle Computational Modeling

The conjugation of antibodies and nanoparticles with high affinity & specificity through receptor-ligand recognition modes is of paramount importance in the development of vehicles which can be used for diagnosis, treatment of cancer and various other diseases, application of immunodiagnostic nano-biosensors etc. The bio-nanocomplex formed by an artificial nanomaterial (nanoliposomes , nanoparticles ) and a biological entity such as an antibody is brought about by the formation of covalent bonds based on their specific chemical and structural properties such as water solubility, biocompatibility, and biodegradability. [5]. There is a requirement of a comprehensive understanding of the relationship of the thermodynamic & kinetic aspects of antibody-membrane association, translational , rotational mobilities of membrane bound antibodies, interactions with the diverse cell surface , circulating molecules and various artificial nanomolecules as well as the conformation. These details are of great importance in the development, application of various nanoscale immunodiagnostic devices. The association of antibodies with cell surfaces is a key molecular event in antibody-mediated immune mechanisms such as phagocytosis, antibody mediated immune dependent cell-mediated cytotoxicity.[6].
Recently it has been noted that there exists certain natural proteins, antibodies, that can recognize specific nanoparticles . For example, a specific antibody from the mouse immune system can specifically recognize derivatized C60 fullerenes with a binding affinity of about 25 nM [5]. From the studies carried out by Noon et al., it is hypothized that the fullerene-binding site is formed at the interface of the light and heavy chains lined with a cluster of shape-complementary hydrophobic amino acid residues. As the covalent modifications of the functionalized fullerenes, occupy only a small fraction of the particle surface area , the largely unoccupied surface would be free to interact with the antibody. Therefore, in order to gain in-depth understanding of the detailed interactions of the nps and the antibody, molecular dynamics simulation is carried out using molecular dynamics simulation; the purpose of our theoretical modeling studies is to be able to identify the energetically favorable binding modes. [4].
For the modeling study, the initial coordinates of the antibody can be made available from the Protein Data Bank (PDB). [5], [7].
The basic assumptions, as a first approximation, during the modeling study would be that the hydrophilic derivatizations do not play a critical role in the predominantly hydrophobic nanomaterial-antibody interactions and that the electronic structure remains undisturbed during the conjugation. The nanoparticle is docked into a suggested binding site from the previously done literature studies.[5]. Polar-hydrogen potential function (PARAM19) and a modified TIP3P water solvent model for the protein is used.[1].
The simulation involves approximately about 300 steps of minimization, using the Steepest Descent and the Newton Raphson method. To reduce the necessary simulation time, a highly efficient method for simulating the localized interactions in the active site of a protein, the stochastic boundary molecular dynamics (SBMD) is used. The reference point for partitioning the system in SBMD was chosen to be near the center of the nanomaterials, which is assumed to be a uniform sphere. The complex nano-bio system can be assumed to be separated into spherical reservoir and reaction zones; the latter is further sub-divided into a reaction region and a buffer region. The atoms in the reaction region are propagated by molecular dynamics, whereas those in the buffer region involve Langevin dynamics are retained using harmonic restoring forces.

Nanotechnology based stem cell therapies for damaged heart muscles

(Nanowerk Spotlight) Regenerative medicine is an area in which stem cells hold great promise for overcoming the challenge of limited cell sources for tissue repair. Stem cell research is being pursued vigorously in laboratories all over the world (except in the U.S., where federal funding for embryonic stem cell research has been severely restricted by the current administration) in the hope of achieving major medical breakthroughs. Scientists are striving to create therapies that rebuild or replace damaged cells with tissues grown from stem cells and offer hope to people suffering from cancer, diabetes, cardiovascular disease, spinal-cord injuries, and many other disorders.
Embryonic stem cells are pluripotent. That means that during normal embryogenesis – the process by which the embryo is formed and develops – human embryonic stem cells can differentiate into all derivatives of the three primary germ layers: ectoderm, endoderm, and mesoderm. Researchers have also found undifferentiated cells – adult stem cells – in children and adults. Unlike embryonic stem cells, the use of adult stem cells in research and therapy is not controversial because the production of adult stem cells does not require the creation or destruction of an embryo.
Often, adult stem cells are not pluripotent but multipotent. That means they can differentiate only into a limited variety of cell type. One such example are mesenchymal stem cells (MSC) – adult stems cells found in bone marrow which can be differentiated into bone, cartilage, fat, and connective tissues – which offer tremendous potential for the repair and or regeneration of damaged tissues and organs.
An area of particular interest is differentiation of MSC into cardiomyocytes (let's simply call them 'heart muscle cells') for damaged heart muscle tissue. In a heart attack, part of the heart muscle loses its blood supply and cells in that part of the heart die, thereby damaging the muscle. This reduces the ability of the heart to pump blood around the body. Considering that coronary heart disease is the leading cause of death in most Western countries (in America with almost half a million fatalities and well over 1 million new and recurrent coronary attacks), stem cell therapy – to repair heart muscle cells, and restore the viability and function of the area already damaged – could have a tremendous impact on modern medicine.
"Recently, carbon nanotubes (CNTs) have been generating great excitement in the fields of bioengineering and drug delivery research – however, very little is known about the affect of CNTs on MSC response" Dr. Valerie Barron tells Nanowerk. "Therefore, the main aim of one of our recent research studies was to investigate the effect of CNTs on human MSC (hMSC) biocompatibility, proliferation and multipotency."
In this study, Barron, a Senior Researcher at the National Centre for Biomedical Engineering Science at National University of Ireland (NUI), together with collaborators from NUI's Regenerative Medicine Institute and Department of Anatomy, investigated a range of different types of CNTs,including single-walled nanotubes (SWCNTs), multi-walled nanotubes (MWCNTs) and functionalized CNTs.
Reporting their findings in the July 12, 2008 online edition of Nano Letters, ("Carbon Nanotubes and Mesenchymal Stem Cells: Biocompatibility, Proliferation and Differentiation"), first-authored by Barron's colleague Emma Mooney, the NUI, Galway scientists revealed that at low concentrations of COOH-functionalized SWCNTs, the CNTs had no significant effect on cell viability or proliferation. In addition, by fluorescently labeling the COOH functionalized SWCNTs, the CNTs were seen to migrate to a nuclear location within the cell after 24h, without adversely affecting the cellular ultrastructure. Moreover, the CNT had no affect on adipogenesis, chondrogenesis or osteogenesis.
Uptake of COOH-functionalized SWCNT by the cell. Fluorescent images of biotinylated CNT within the cell after (a) 24 h, (b) 48 h, and (c) 6 days and (d) hMSC alone (scale bar 130 µm). (Reprinted with permission from American Chemical Society)
Previous research has shown that CNTs migrate into cancer cells and therefore can be used for biomolecule delivery directly into the cells. This is the first study to examine the effect of CNTs on hMSC and as such is important for new and emerging technologies in drug delivery, tissue engineering, and regenerative medicine. At low concentrations, CNTs have minimal affect on MSC viability and multipotency. Therefore, they have great potential to advance the field in a number of ways including
Manipulation of MSC differentiation pathways;
Development of nanovehicles for delivering biomolecule-based cargos to mesenchymal stem cells;
Creation of novel biomedical applications for electroactive carbon nanotubes in combination with mesenchymal stem cells."
In a previous position at Trinity College Dublin, Barron had worked in Werner Blau's Molecular Electronics and Nanotechnology group where she gained a tremendous appreciation for carbon nanotubes. "As a biomaterials scientist, I could see their potential in biomedical applications" she says. At NUI, Galway she therefore teamed up with Murphy to examine the effect of CNTs on MSC differentiation. Both researchers were aware of the fact that, since there is no clinical therapy available for the repair of damaged heart muscle, there exist tremendous opportunities for the creation of novel nanotechnology based therapies.
Since carbon nanotubes are electrically conductive, there is a huge potential for the manipulation of MSC differentiation pathways to create electroactive cells such as those found in the heart. In particular, specific applications could result in novel MSC based cell therapies for electroactive tissue repair; novel biomolecule delivery vehicle for manipulation of MSC differentiation pathways; and electroactive CNT scaffolds for damaged electroactive tissues.
"At present, we are developing a novel electrophysiological environment to promote MSC differentiation towards a cardiomyocyte lineage" says Barron. "In the short-term we plan to focus on optimizing this approach to develop nanotechnology based cell therapies. In the longer term we hope to use the nanotubes as delivery vehicles for a range of different biomolecules for the manipulation of MSC differentiation pathways towards a range of different cell types."

Nanotechnology and Stem Cell heart muscle

Applications that combine Nanoparticles with Stem Cells
Nanotechnology and biomedical treatments using stem cells (such as therapeutic cloning) are among the newest veins of biotechnological research. Even more recently, scientists have begun finding ways to marry the two. Since about 2003, examples of nanotechnology and stem cells combined have been accumulating in scientific journals. While the potential applications for nanotechnology in stem cell research are countless, three main categories can be assigned to their use:
tracking or labeling
delivery
scaffold/platforms
Certain nanoparticles have been in use since the 1990's, for applications such as cosmetic/skin care delivery, drug delivery and labeling. Experimentation with different types of nanoparticles such as quantum dots, carbon nanotubes and magnetic nanoparticles, on somatic cells or microorganisms, has provided the background from which stem cell research has been launched. As a little known fact, the first patent for the preparation of nanofibers was recorded in 1934. These fibers would eventually become the foundation of scaffolds for stem cell culture and transplantation – over 70 years later.
Visualizing Stem Cells Using MRI and SPIO particles
Research on the applications of nanoparticles for magnetic resonance imaging (MRI) has been pushed by the need to track stem cell therapeutics. A common choice for this application are superparamagnetic iron oxide (SPIO) nanoparticles, which enhance the contrast of MRI images. Some iron oxides have already been approved by the FDA. The different types of particles are coated with different polymers on the outside, usually a carbohydrate. MRI labeling can be done by attaching the nanoparticles to the stem cell surface or causing uptake of the particle by the stem cell through endocytosis or phagocytosis. Nanoparticles have helped add to our knowledge of how stem cells migrate in the nervous system.
Labeling using Quantum Dots
Quantum dots (Qdots) are nano-scale crystals that emit light, and are comprised of atoms from groups II-VI of the periodic table, often incorporating cadmium. They are better for visualizing cells than certain other techniques such as dyes, because of their photostability and longevity. This also allows their used for studying cellular dynamics while differentiation of stem cells is in progress.
Qdots have a shorter track record for use with stem cells than SPIO/MRI, and have only been used in vitro so far, because of the requirement for special equipment to track them in whole animals.

Nucleotide Delivery for Genetic Control,

Genetic controls, using DNA or siRNA, is emerging as a useful tool for controlling cellular functions in stem cells, particularly for directing their differentiation. Nanoparticles can be used to replace the traditionally used viral vectors, such as retroviruses, which have been implicated in causing complications in whole organisms such as inducing mutations leading to cancer. Nanoparticles offer a less expensive, more easily producible vector for transfection of stem cells, with lower risk of immunogenicity, mutagenicity or toxicity. A popular approach is to use cationic polymers that interact with DNA and RNA molecules. There is also room for development of smart polymers, with features such as targeted delivery or scheduled release. Carbon nanotubes with different functional groups have also been tested for drug and nucleic acid delivery into mammalian cells, but their use in stem cells has not been investigated to a large extent.
Optimizing the Stem Cell Environment
A significant area of study in stem cell research is that of the extracellular environment and how conditions outside the cell send signals for the control of differentiation, migration, adhesion and other activities. The extracellular matrix (ECM), consists of molecules secreted by cells such as collagen, elastin, and proteogylcan. The properties of these excretions and chemistry of the environment they create, provide direction for stem cell activities. Nanoparticles have been used to engineer different patterned topographies that mimic the ECM, for studying their effects on stem cells.
A major complication encountered with stem cell therapies has been the failure of injected cells to engraft to target tissues. Nanoscale scaffolds improve cell survival by aiding the engrafting process. Nanofibers spun from synthetic polymers such as poly(lactic acid) (PLA), or natural polymers of collagen, silk protein or chitosan, provide channels for alignment of stem and progenitor cells. The ultimate goal is to determine what scaffold composition best promotes proper adhesion and proliferation of the stem cells and use this technique for stem cell transplantations. However, it appears the morphology of cells grown on nanofibers may differ from cells grown on other media, and few in vivo studies have been reported.

Nanotechnology and Stem Cell Applications

Nanotechnology and Stem Cell Applications

Applications that combine Nanoparticles with Stem Cells:
Nanotechnology and biomedical treatments using stem cells (such as therapeutic cloning) are among the newest veins of biotechnological research. Even more recently, scientists have begun finding ways to marry the two. Since about 2003, examples of nanotechnology and stem cells combined have been accumulating in scientific journals. While the potential applications for nanotechnology in stem cell research are countless, three main categories can be assigned to their use:
tracking or labeling
delivery
scaffold/platforms
Certain nanoparticles have been in use since the 1990's, for applications such as cosmetic/skin care delivery, drug delivery and labeling. Experimentation with different types of nanoparticles such as quantum dots, carbon nanotubes and magnetic nanoparticles, on somatic cells or microorganisms, has provided the background from which stem cell research has been launched. As a little known fact, the first patent for the preparation of nanofibers was recorded in 1934. These fibers would eventually become the foundation of scaffolds for stem cell culture and transplantation – over 70 years later.
Visualizing Stem Cells Using MRI and SPIO particles
Research on the applications of nanoparticles for magnetic resonance imaging (MRI) has been pushed by the need to track stem cell therapeutics. A common choice for this application are superparamagnetic iron oxide (SPIO) nanoparticles, which enhance the contrast of MRI images. Some iron oxides have already been approved by the FDA. The different types of particles are coated with different polymers on the outside, usually a carbohydrate. MRI labeling can be done by attaching the nanoparticles to the stem cell surface or causing uptake of the particle by the stem cell through endocytosis or phagocytosis. Nanoparticles have helped add to our knowledge of how stem cells migrate in the nervous system.
Labeling using Quantum Dots
Quantum dots (Qdots) are nano-scale crystals that emit light, and are comprised of atoms from groups II-VI of the periodic table, often incorporating cadmium. They are better for visualizing cells than certain other techniques such as dyes, because of their photostability and longevity. This also allows their used for studying cellular dynamics while differentiation of stem cells is in progress.
Qdots have a shorter track record for use with stem cells than SPIO/MRI, and have only been used in vitro so far, because of the requirement for special equipment to track them in whole animals.

Biotechnology and programmable positional control

Schematic illustration of a Stewart platform. The lower (blue) triangle forms the base, while the upper (green) triangle froms the platform.
The position and orientation of the platform with respect to the base can be controlled in six degrees of freedom (X, Y, Z, rool, pitch, and yaw) by adjusting the lengths of the six gray struts.


Today's SPMs are large, relatively slow, and will never make mole quantities of product. If we really want positional assembly to make products in the volume that ribosomes make proteins, we must have small, fast positional devices7. Yet it seems unlikely that biotechnology will directly give us a molecular robotic arm.
Which brings us to the Stewart platform8,9,10. This device, basically an octahedron six of whose struts can be lengthened or shortened under programmatic control (see illustration), provides six degree of freedom positional control for the "platform," (the green triangle at the top of the octahedron) with respect to its base (the blue triangle at the bottom of the octahedron). The ability to make an octahedron does not seem beyond the capabilities of biotechnology (in the broad sense of the term), particularly when the ability to self assemble a truncated octahedron has already been demonstrated by Seeman2.
All we need are twelve stiff struts, some way to make their ends stick together, and some way to lengthen or shorten six of those struts. As the latter seems the harder problem, we discuss one possible approach to solving it.
Consider a single strut: how can we change its length? One way would be to use two struts that overlap, and then make them slide past each other in a controlled fashion. Suppose that the first strut is made of three repeat units, ABCABCABCABCABC...., while the second strut is also made of three repeat units, XYZXYZXYZXYZ.... If we want to combine these two struts into one long strut, then we have to join them together. Suppose we use "joiners" that have two ends: one end binds to the A units of the first strut, while the other end binds to the X units of the second strut. Then, as illustrated above, the two struts would be held together by this a-x joiner to form a single longer strut.
But how can we change the position of the ABC strut with respect to the XYZ strut? First, we add a c-y joiner. These new joiners will bridge between the C and Y units of the ABC and XYZ struts. They will at first be strained, but as we add more and more c-y joiners they will start to balance out the a-x joiners. If we now wash the a-x joiners out of solution (the simplest arrangement would be to anchor the octahedron in place by a tether, and flow a solution with an appropriate concentration of joiners past them), then the c-y joiners will dominate the linkage between the two struts leading to the results in the final illustration, below. At this point, the ABC and XYZ struts have moved past each other by one monomer.
If we repeat the whole process again, this time washing in a b-z joiner and washing out the c-y joiner, we can again move the two struts over by one monomer. Finally, if we wash in an a-x joiner and wash out the b-z joiner, we are back where we started. By repeating the whole cycle, we can move the ABC strut past the XYZ strut as much as we want. By running the cycle in reverse, we can reverse the motion. In essence, we have a three-phase linear motor. While this is slow (it's limited by the speed at which we can wash the joiners into and out of position) it does provide a flexible means of controlling the length of the strut, and does not seem hopelessly difficult.
The essential point here is not that this particular approach is the right one or even necessarily a good one, but that biotechnology and self assembly can be used to make positional devices. This is just one possible way: there are a great many more.

Positional assembly of Biotechnology as a route to nanotechnology

There are two main ways to assemble parts. In self assembly, the parts move randomly under the influence of thermal noise and explore the space of possible mutual orientations. If some particular arrangement is more stable, then it will be preferred. Given sufficient time, this preferred arrangement will be adopted. For example, two complementary strands of DNA in solution will eventually find each other and stick together in a double-helical configuration.
In positional assembly, some restoring force keeps the part positioned at or near a particular location, and two parts are assembled when they are deliberately moved into close proximity and linked together. While common at the scale of humans (we commonly hold, position and assemble parts with our hands) this ability is still quite novel at the molecular scale. Thermal noise still plays a significant role, as "holding" a molecular part does not provide absolute certainty about its position but instead imposes a bias on the range of positions it can adopt. Using a linear approximation, an object might be subjected to a restoring force F which is proportional to its distance from the desired location, i.e., F = ks x, where x is the distance between the part and its desired location, and ks is the restoring force.
Restoring forces on the order of 10 N/m (Newtons/meter) or better can be achieved with scanning probe microscopes, which can position an object quite accurately. The fundamental equation relating positional uncertainty, temperature and stiffness is4:
s2 = kbT/ks
Where s is the mean error in position, kb is Boltzmann's constant, T is the temperature in Kelvins, and ks is the "spring constant" of the restoring force. If ks is 10 N/m, the positional uncertainty s at room temperature is ~0.02 nm (nanometers). This is accurate enough to permit alignment of molecular parts to within a fraction of an atomic diameter. It is important to remember, however, that the actual error could be many times s. The probability that the actual error is xerr is exp[-ks xerr2/(2s2)] / (s sqrt(2p)). Errors of a few times s are common, but errors of 20 times s would be extremely unlikely.
The distinction between self assembly and positional assembly is not binary, but moves continuously along a scale depending on the positional uncertainty (which is a function of the restoring force and the temperature). When the positional uncertainty s is large, we are near the self assembly end of the spectrum. When s is small, we are at the positional assembly end of the spectrum. Intermediate points along this spectrum are occupied by, for example, a molecule "tethered" to an SPM tip by a polymer; or an object held by optical tweezers (a restoring force of 10-4 N/m implies a positional uncertainty s at room temperature of ~6 nm).
While the SPM provides programmable positional control (you can adjust x, y and z to essentially any values), a simple form of positional assembly can also be seen in enzymes which bind two substrate molecules. The two bound molecules are positioned with respect to each other, thus facilitating their assembly. A limited form of positional assembly is also used in the ribosome, which can position the end of a growing protein adjacent to the next amino acid to be incorporated into that protein5.
This combination of positional assembly and self assembly can also be seen at the macroscopic scale. The vibratory bowl feeder6 is commonly used in manufacturing to position parts with sizes on the order of a centimeter. The bowl is shaken by a motor, causing parts in the bowl to bounce onto and along a spiral track leading out of the bowl. By careful design of the track, parts in the right orientation continue to move along it, out of the bowl and into further assembly steps. Parts in the wrong orientation are bounced back into the bowl, where they can try again to move up the spiral path leading out of the bowl.
While the power of self assembly has been amply demonstrated by the wide range of complex molecular structures it has made (including a remarkable range of biological structures), we have barely begun to explore the power of positional assembly at the molecular scale. Despite this, it seems clear that this new capability will play a major role in our future ability to synthesize molecular structures. The power of positional assembly has been amply demonstrated at the macroscopic scale in today's factories and by our own ability to make things with our hands. While its application at the molecular scale will differ in many details, it will provide a new and remarkably powerful tool for extending the range of structures that we can make.

Biotechnology as a route to nanotechnology

Nanotechnology is creating a growing sense of excitement because we see an opportunity of unprecedented magnitude looming on the horizon: the ability to arrange and rearrange molecular structures in most of the ways consistent with physical law. This will have a pervasive impact on how we manufacture almost everything -- what is manufacturing but a way to arrange atoms? If we can arrange atoms with greater precision, at lower cost, and with greater flexibility then almost all the familiar products in our world will be revolutionized. To name just three: we'll pack more computational power into a sugar cube than exists in the world today, we'll make inexpensive structural materials that are as light and strong as diamond (which will have a major impact on the aerospace industry), and we'll make surgical tools and instruments that are molecular in their size and precision, able to intervene directly at the fundamental level where most sickness and disease are caused.
Underlying the excitement is a very simple fact: while atoms can be arranged in almost infinite permutations, today we can make only an infinitesimal fraction of what is possible. Very roughly, if we can pack 100 atoms into a cubic nanometer, and each atom can be any of the approximately 100 elements, then there are something like 100100 different ways we can arrange the atoms in just a single cubic nanometer. A cubic micron expands this to 100100000000000, while an object the size of you or me makes even this number seem vanishingly small. The goal that now seems possible: to take a healthy bite out of this enormous range of possibilities; to make most of the things that are possible, rather than an infinitesimally small fraction.
In 1959 Feynman said: "The principles of physics, as far as I can see, do not speak against the possibility of maneuvering things atom by atom. It is not an attempt to violate any laws; it is something, in principle, that can be done; but in practice, it has not been done because we are too big." More recently, Smalley said "Most interesting structures that are at least substantial local minima on a potential energy surface can probably be made one way or another."
The breathtaking magnitude of this opportunity is attracting interest. Neal Lane, the Director of NSF, said: "The possibilities of nanotechnology are endless. Entirely new classes of incredibly strong, extremely light and environmentally benign materials could be created" and went on to discuss inexpensive superconductors and medical applications. NSF is backing up this rhetoric with grants. NASA has a computational molecular nanotechnology research group examining the ways in which this technology can be used to advance the exploration and human habitation of space. IBM is doing pathbreaking research to revolutionize computing. Storing one bit in a few atoms no longer seems outlandish, and molecular switches will someday replace the bulky devices made today using optical lithography.
As we move beyond the vision and start asking how we are going to do this and how long it will take, opinions begin to diverge. Should we make ever better scanning probe microscopes (SPM's)? These remarkable instruments have already demonstrated an ability to move atoms and molecules on a surface in a controlled way (often spelling out names of interest to the researchers or their sponsors), but have so far been confined to two dimensions. Stacking molecules one on top of another is the next obvious goal, which will no doubt be accomplished in the next few years. Could these versatile instruments go on to make molecular machines?
Or perhaps the design and modification of proteins and their self assembly will provide the key to progress? Living systems already use many molecular machines, such as molecular motors. Could we adapt them to our own uses, perhaps using them to power tiny pumps or open and close tiny valves?1
A computer generated image of a truncated octahedron experimentally synthesized from DNA by Nadrian Seeman.
There are many novel uses of existing biopolymers that could provide us with new tools. DNA, for example, is known primarily for its ability to encode information. But it can also produce structures as complex as a truncated octahedron2 and even provide power when it's chemical conformation changes in response to changes in its environment3.
The great diversity of proposals, ideas, and experimental capabilities makes it very difficult to predict exactly how we will proceed towards the more general goals of nanotechnology. Yet there are a few principles that seem both powerful enough and clear enough that they can provide some sort of framework for orienting ourselves. The first principle we consider is that of positional assembly.

Nanotechnology Research Labs

Nanotechnology Research Labs
This page provides links to research labs, organized by topic, which have useful information about their activities on their Web sites. This isn't an complete list, but a good jumping off point for those interested in the world of nanotechnology research. Click a topic heading below to go to a discussion of that topic on this web site. Click a lab's name to go to its Web site.
The first set of labs are doing research but do not make their facilities available to outside researchers; the second set do allow users to either submit materials for study or rent their facilities for their own research.
Academic, Government, and Corporate Labs
These labs are doing research in the following categories.
Nanoelectronics
IBM Nanoscale science and technology group
Institute for Nanoelectronics and Computing
HP Labs Quantum Science Research Group
Center for Electron Transport in Molecular Nanostructures

Nanotechnology Companies and Products

The applications pages on this site list companies that are involved in working with nanotechnology who have useful information about their nanotechnology activities on their Web sites. We thought it would be useful to you to have a handy listing of those companies in one place. This isn't an complete list of companies in the field, but a good jumping off point for those interested in nanotechnology companies. Click a product category heading below to quickly go to the associated list of companies. Click a company's name to go to its Web site.

Company
Product
BioDelivery Sciences
Oral drug delivery of drugs encapuslated in a nanocrystalline structure called a cochleate
CytImmune
Gold nanoparticles for targeted delivery of drugs to tumors
Invitrogen
Qdots for medical imaging
Nucryst
Antimicrobial wound dressings using silver nanocrystals
Luna Inovations
Bucky balls to block inflammation by trapping free radicals
NanoBio
Nanoemulsions for nasal delivery to fight viruses (such as the flu and colds) or through the skin to fight bacteria
NanoBioMagnetics
Magnetically responsive nanoparticles for targeted drug delivery and other applications

Nanotube Applications

The properties of nanotubes have caused researchers and companies to consider using them in several fields. For example, because carbon nanotubes have the highest strength to weight ratio of any known material, researchers at NASA are combining carbon nanotubes with other materials into composites that can be used to build lightweight spacecraft.
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Another property of nanotubes is that they can easily penetrate membrances such as cell walls. In fact, nanotubes long, narrow shape make them look like miniature needles, so it makes sense that they can function like a needle at the cellular level. Medical researchers are using this property by attaching molecules that are attracted to cancer cells to nanotubes to deliver drugs directly to diseased cells.
Another interesting property of carbon nanotubes is that their electrical resistance changes significantly when other molecules attach themselves to the carbon atoms. Companies are using this property to develop sensors that can detect chemical vapors such as carbon monoxide or biological molecules.
These are just a few of the potential uses of carbon nanotubes The following survey of carbon nanotube applications introduces these and many other uses. Click on any of the links below to go to a more detailed explanation.

Nanotechnology in Electronics (Nanoelectronics)

How can nanotechnology improve the capabilities of electronic components?
Nanoelectronics holds some answers for how we might increase the capabilities of electronics devices while we reduce their weight and power consumption. Some of the nanoelectronics areas under development, which you can explore in more detail by following the links provided in the next section, include the following topics.
Improving display screens on electronics devices. This involves reducing power consumption while decreasing the weight and thickness of the screens.