Table of contents

Technological strength indicators (TSIs) based on patent statistics for 1975–2000 are used to analyse patenting of nanotechnology in the USA, and to compile international rankings for the top 12 foreign patenting countries (namely Australia, Canada, France, Germany, Great Britain, Italy, Japan, Korea, the Netherlands, Sweden, Switzerland and Taiwan). As the indicators are not directly observable, various proxy variables are used, namely the technological specialization index for national priorities, patent shares for international presence, citation rate for the contribution of patents to knowledge development and rate of assigned patents for potential commercial benefits. The best performing country is France, followed by Japan and Canada. It is shown that expertise and strength in nanotechnology are not evenly distributed among the technologically advanced countries, with the TSIs revealing different emphases in the development of nanotechnology.

The scientific community needs a rapid and reliable way of accurately determining the stiffness of atomic-force microscopy cantilevers. We have compared the experimentally determined values of stiffness for ten cantilever probes using four different methods. For rectangular silicon cantilever beams of well defined geometry, the approaches all yield values within 17% of the manufacturer's nominal stiffness. One of the methods is new, based on the acquisition and analysis of thermal distribution functions of the oscillator's amplitude fluctuations. We evaluate this method in comparison to the three others and recommend it for its ease of use and broad applicability.

We present a colorimetric detection method which is able to detect biotinylated oligonucleotides hybridized to thiolated complementary strands bound to a gold surface. Unlike previous colorimetric detection methods, this technique has the advantage of providing spatial information which is of higher resolution than that of an optical microscope, and can also be used on a gold surface. Bulk concentrations down to 10⁻⁹ M of biotinylated oligonucleotides were detectable representing fewer than 7000 molecules of hybridized DNA on a microarray-sized spot (≈ 35μm). This technique has potential for DNA detection in molecular electronics and molecular assembly applications, where a high-resolution detection on metal surfaces is required.

A new method for the growth of high-quality ZnO nanoparticles is presented here; it is a novel, low-cost, and easy operation. This approach, using solid-state heat decomposition at low temperature, allows one to produce ZnO nanoparticles with relatively high dispersivity. The optical properties of the ZnO nanoparticles have been investigated. It is demonstrated that ZnO nanoparticles show strong ultraviolet emission, while the low-energy visible emission is nearly fully quenched at room temperature. This is a result of the high quality of the ZnO. X-ray diffraction patterns reveal that the ZnO nanoparticles have polycrystalline hexagonal wurtzite structure. The Raman spectrum shows a typical resonant multi-phonon form for the ZnO nanoparticles. Similar synthesis routes for other metal oxide nanoparticles may be possible.

We use magnetotunnelling spectroscopy as a non-invasive probe to produce two-dimensional spatial images of the probability density of an electron confined in a self-assembled semiconductor quantum dot. The images reveal clearly the elliptical symmetry of the ground state and the characteristic lobes of the higher-energy states.

A silver nanowire array micropolarizer within an anodic alumina membrane (AAM) was fabricated by anodization of pure Al foil and electrodeposition of Ag, respectively. X-ray diffraction, scanning electron microscopy, and transmission electron microscopy investigations reveal that the nanowires are essentially single crystals, and have an average diameter of 90 nm. Spectrophotometer measurements show that the silver nanowire arrays embedded in the AAM can only transmit vertically polarized light to the wires. An extinction ratio of 25–26 dB and average insertion loss of 0.77 dB in the wavelength range 1–2.2 μm were obtained, respectively. Therefore the Ag nanowire/AAM can be used as a wire-grid type polarizer.

Si_1−xGe_x nanocrystals were obtained by means of laser-induced crystallization of a-SiGe films deposited by plasma-enhanced chemical vapour deposition. The crystallization was confirmed by x-ray diffraction spectroscopy, Fourier transmission infrared spectroscopy and atomic force microscopy; the average diameter of the nanocrystals was about 4.1 nm. The Ge fraction component was estimated to be 0.3 from the Raman spectra. In the near-infrared photoluminescence (PL) a peak located at 1.357 eV was observed. For Si_1−xGe_x nanocrystals about 4.1 nm in diameter, the PL is considered to originate from the recombination of electron–hole pairs confined in Si_1−xGe_x nanocrystals, and direct recombination and indirect recombination both occur in the recombination process. Another possible cause of near-infrared PL is the presence of defects at the interface between Si_1−xGe_x nanocrystals and the surrounding matrix and/or in the matrix region itself.

Aluminium nitride (AlN) nanocrystals were prepared by the benzene thermal method at low temperature (110^oC) and low pressure (0.12–0.14 MPa). Owing to the catalytic effect of AlN nanocrystals, 5–8% benzene was converted at 150^oC and 0.1–0.3 MPa into several polymers, mainly cyclohexylbenzene, 1, 1'-biphenyl and 1', 1-methylenebisbenzene. In contrast, when the pure benzene without AlN nanocrystals was heated to 200^oC, no new product could be detected. The mechanism of the polymerization of benzene in the presence of AlN nanocrystals is briefly discussed on basis of a model of the coordination chemistry.

We studied the pattern transfer fidelity of nanoimprint lithography (NIL) by patterning sub-micron MESFET gates on six-inch wafers. The critical dimensions (CD) of the gate patterns on the mould, imprinted in resist, as well as after oxygen reactive ion etching (RIE) and metal lift-off were measured, separately, using an ultrahigh-resolution scanning electron microscope. Comparison of the measurements reveals that the as-imprinted gates in resist are 5.2% (or 37 nm) on average larger than those on the mould with a standard deviation of 1.2% (or 8 nm), and the gates after oxygen RIE and metal lift-off are 42% (or 296 nm) on average larger than those on the mould with a standard deviation of 8% (or 30 nm). Compared with photolithography, NIL has better pattern transfer fidelity with CD controls about four times smaller.

It is essential to find a technique for assembling carbon nanotubes into a desired functional structure if we are to realize advanced functions. This paper describes large-area synthesis of wire-like building blocks consisting of carbon nanofibres by electric field-assisted growth on a substrate. The wire-like building blocks with diameters of a few micrometres are synthesized by using chemical vapour deposition (CVD) on a substrate on which interdigitated finger electrodes are formed by photolithography in order to enable electrical control of the growth. The metal electrodes are buried in silicon dioxide in order to electrically isolate each electrode, and then nickel thin film, a catalyst for the growth, is deposited on the top surface. It is found that the electric field enhances the growth of carbon nanofibres only on negatively biased electrodes. As carbon fibres grow, compressive stress is induced in the nanofibre film due to the congestion; this causes the film to lift from the substrate and leads to a rounded shape, and finally free-standing wire-shaped building blocks are formed along the narrow electrodes. In contrast, carbon nanofibres formed by CVD using an iron catalyst tend to align perpendicular to the finger electrodes due to the electrostatic force.

Electric-field induced surface modification of Au is used to create stable sub-nanometre-scale gaps between Au leads. Electron tunnelling current is measured as a function of the molecular environment. We explore the influence of water molecules on tunnelling conductance. At small voltage, water molecules do not influence the conductance. At large voltage, a strong static electric field between the leads induces trapping of H₂O molecules from the water vapour. At room temperature, trapped water molecules increase the tunnelling barrier height, in agreement with the workfunction of water. We estimate that the resistance of a single trapped water molecule at 5 V is of order 100 GΩ.

Various characteristics of the growth of carbon nanotubes (CNTs) were examined by in situ optical interference patterns. A dc plasma chemical vapour deposition technique was used to grow the CNTs. The optical interference curves provided considerable in situ information such as the length, the alignment and related growth properties of CNTs. Curled CNTs have relatively small numbers of oscillations compared to well-aligned nanotubes during the same growth time. Sparse and short CNTs have shown a high reflectance with no interference oscillations. The alignment of the CNTs was strongly dependent on variations in the NH₃ pre-treatment current. The electric field has a large effect on the direction of growth of well-aligned CNTs with high packing density. However, curled CNTs do not appear to be affected by the presence of the electric field. This optical interference method provides an in situ and effective method for monitoring the growth characteristics of CNTs.

GaN nanowires have been synthesized by ammoniating Ga₂O₃ oxide thin films. Ga₂O₃ films with a thickness of ∼500 nm were deposited on quartz substrates by radio frequency magnetron sputtering. X-ray diffraction, scanning electronic microscope, transmission electronic microscope and high-resolution TEM results show that the majority of the GaN nanowires have a single-crystal hexagonal wurtzite structure with major axis [110] alignment. A minority are polycrystalline, composed of overlapped parallelepiped GaN nanocrystals, which gives the wires a herringbone topography. The diameters of the wires range from 10 to 90 nm and the lengths are up to 50 μm. The achievement of GaN nanowires by ammoniating Ga₂O₃ presents a novel method for synthesizing one-dimensional nanometre materials without the assistance of a template or a catalyst.

Oscillatory behaviour was detected in the dependences of the transport properties (electrical conductivity, Hall coefficient, charge carrier mobility, Seebeck coefficient and thermoelectric power factor) on the PbTe layer thickness d (d = 2–200 nm) in (001) KCl/PbTe/EuS quantum well (QW) structures at room temperature. The non-monotonic character of these dependences is attributed to quantum size effects, which manifest themselves in PbTe QWs at sufficiently small values of d. The positions of the extrema in the thickness dependences of the transport properties shift with changing electron concentration in PbTe QWs.

Using picosecond millimetre-wave impulses we probe the electronic structure and dynamics of electrons in a single quantum dot—the artificial atom—which is essential for understanding their applications such as computational elements and detectors. Although dc transport shows strong elastic cotunnelling in the Coulomb blockade (CB) regime, this effect is suppressed under picosecond impulses whose energies are commensurate with those of the dot. Under non-zero bias we find excited-state resonances in the induced complex photoconductance as well as strong deviations of the dot capacitance compared to equilibrium values according to the 'orthodox model' of CB, a direct signature of the relaxation times of single-electron tunnelling.

Nanocrystalline silicon films, with an average nanocrystal size of about 10 nm, obtained by boron implantation of amorphous silicon layers, have been studied by remote-beam-induced current (REBIC) in a scanning tunnelling microscope (STM) and by current imaging tunnelling spectroscopy. STM images reveal a cell structure with cell sizes of about 200 nm. STM–REBIC images display space-charge regions associated with the cell boundaries. The STM–REBIC contrast has been found to depend on the implantation dose and the thermal treatment given to the sample. The results show the capability of STM–REBIC to image electrically active regions in nanocrystalline silicon films with a resolution of up to 10 nm.

We demonstrate an optical recording on a CdSe nanocrystal (NC) thin film by using near-field scanning optical microscopy. Both positive and negative luminescent images were recorded on the CdSe NC thin film by utilizing photoluminescence (PL) enhancement and photobleaching, respectively. Since the PL enhancement is reversible, CdSe NC thin films are exploitable as rewritable optical recording media. On the other hand, CdSe NC thin films can also be used as write-once media when one utilizes photobleaching. The possibility of high-density optical storage on CdSe NC thin film is shown.

Atomic force microscopy was used to map the surface topographies and the fine details of cells from the T98 human glioblastoma brain tumour cell line. The cells were plated on collagen substrate within growth media, and then exposed to air during the microscopy sessions. Over the course of these studies an example of a cytostructural invadopodia was observed extending in a straight line from one cell to another over a distance of approximately 80 µm, but with an estimated deviation from linearity over the length of its path of only ≈ 8 nm µm⁻¹, i.e., < 1%. The remarkable straightness of its path suggests that strong cell-to-cell signalling processes are at work during even this earliest stage of tumorigenesis. A better understanding of the nanoscale morphologies and mechanics of novel cytostructural elements like this particular form of invadopodia may provide insights on new modalities of brain tumour treatment.

We propose a device which implements a solid-state nanostructured electron entangler. It consists of a single-walled carbon nanotube connected at both ends to normal state electrodes and coupled in its middle part to a superconducting nanowire. Such a device acts as an electronic beam splitter for correlated electrons originating from the superconductor. We first show that it can be used to detect positive (bosonic-like) noise correlations in a fermionic system. Furthermore, it provides a source for entangled electrons in the two arms of the splitter. To generate entangled electron states, we propose two kinds of set-up based either on spin or energy filters. They respectively consist of ferromagnetic pads and of a system of electrostatic gates which define quantum dots. The fabrication of this device would require state-of-the-art nanofabrication techniques, carbon nanotube synthesis and integration, as well as atomic force microscopy imaging and manipulation.

We demonstrate continuous label-free detection of two cardiac biomarker proteins (creatin kinase and myoglobin) using an array of microfabricated cantilevers functionalized with covalently anchored anti-creatin kinase and anti-myoglobin antibodies. This method allows biomarker proteins to be detected via measurement of surface stress generated by antigen–antibody molecular recognition. Reference cantilevers are used to eliminate thermal drifts, undesired chemical reactions and turbulences from injections of liquids by calculating differential deflection signals with respect to sensor cantilevers. The sensitivity achieved for myoglobin detection is below 20 µg ml⁻¹. Both myoglobin and creatin kinase could be detected independently using cantilevers functionalized with the corresponding antibodies, in unspecific protein background. This approach permits the use of up to seven different antigen–antibody reactions simultaneously, including an additional thermomechanical and chemical in situ reference. Applications lie in the field of early and rapid diagnosis of acute myocardial infarction.

Optical lithography is the method of choice for mass production of electronic as well as acoustic devices. Cost issues, in particular, make it superior over slow but high-resolution methods, such as electron beam lithography. Also, its applicability for nonconductive substrates is an important feature for acoustic device fabrication on ceramics. In order to be able to continue the use of diffraction-limited optical lithography, new schemes have been developed that enhance the resolution. Rather complex phase-shifting masks, for instance, alter both the amplitude and the phase of the exposing light and lead to higher resolution. However, by using an elastomeric phase mask derived from a photoresist master (made by conventional photolithography), features as small as 90 nm have been demonstrated. We report on the application of the near-field phase shift technique for the fabrication of surface acoustic wave (SAW) devices. This technique is best suited for the fabrication of narrow electrode gap SAW devices that are designed for the efficient SAW excitation at higher harmonics. The combination of near-field phase shift lithography with narrow-gap SAW designs thus opens up a way for simple and low-cost SAW devices operating above 5 GHz.

Silver nanoparticles in the size range of 2–5 nm were synthesized extracellularly by a silver-tolerant yeast strain MKY3, when challenged with 1 mM soluble silver in the log phase of growth. The nanoparticles were separated from dilute suspension by devising a new method based on differential thawing of the sample. Optical absorption, transmission electron microscopy, x-ray diffraction and x-ray photoelectron spectroscopy investigations confirmed that metallic (elemental) silver nanoparticles were formed. Extracellular synthesis of nanoparticles could be highly advantageous from the point of view of synthesis in large quantities and easy downstream processing.

Layer-by-layer (LBL) films of a semiconducting polymer (POMA) alternated with a polyelectrolyte (PVS), adsorbed onto silicon oxide, mica, ITO/glass, Au/Cr/glass, hydrophilic and hydrophobic glass were studied by atomic force microscopy (AFM). The samples were characterized LBL with the AFM operating in the contact, friction and tapping modes, which allowed us to determine their morphological surface properties such as roughness, mean grain size, grain boundaries and power spectrum density. Their film thickness was measured by AFM using the tip as a scraping tool. Surface roughness increases with the number of bilayers until a constant value is reached. This is in agreement with the observed increase in the adsorbed amount (per layer) of POMA as the number of bilayers is increased, which also saturates after several bilayers. It is shown that the 3D growth behaviour indicates a similar microscopic mechanism for all systems under study, pointing to a stochastic growth process of the Eden model type, but strongly influenced by initial roughness and water affinity of the virgin substrates. The crystalline or amorphous nature of the substrates does not seem to influence the growth process.

1. Introduction

Despite unprecedented government funding and public interest in nanotechnology, few can accurately define the scope, range or potential applications of this technology. One of the most pressing issues facing nanoscientists and technologists today is that of communicating with the non-scientific community. As a result of decades of speculation, a number of myths have grown up around the field, making it difficult for the general public, or indeed the business and financial communities, to understand what is a fundamental shift in the way we look at our interactions with the natural world. This article attempts to address some of these misconceptions, and explain why scientists, businesses and governments are spending large amounts of time and money on nanoscale research and development.

2. What is nanotechnology?

Take a random selection of scientists, engineers, investors and the general public and ask them what nanotechnology is and you will receive a range of replies as broad as nanotechnology itself. For many scientists, it is nothing startlingly new; after all we have been working at the nanoscale for decades, through electron microscopy, scanning probe microscopies or simply growing and analysing thin films. For most other groups, however, nanotechnology means something far more ambitious, miniature submarines in the bloodstream, little cogs and gears made out of atoms, space elevators made of nanotubes, and the colonization of space. It is no wonder people often muddle up nanotechnology with science fiction.

3. What is the nanoscale?

Although a metre is defined by the International Standards Organization as `the length of the path travelled by light in vacuum during a time interval of 1/299 792 458 of a second' and a nanometre is by definition 10^{- 9} of a metre, this does not help scientists to communicate the nanoscale to non-scientists. It is in human nature to relate sizes by reference to everyday objects, and the commonest definition of nanotechnology is in relation to the width of a human hair.

Unfortunately, human hairs are highly variable, ranging from tens to hundreds of microns in diameter (10^-6 of a metre), depending on the colour, type and the part of the body from which they are taken, so what is needed is a standard to which we can relate the nanoscale. Rather than asking anyone to imagine a millionth or a billionth of something, which few sane people can accomplish with ease, relating nanotechnology to atoms often makes the nanometre easier to imagine. While few non-scientists have a clear idea of how large an atom is, defining a nanometre as the size of 10 hydrogen, or 5 silicon atoms in a line is within the power of the human mind to grasp. The exact size of the atoms is less important than communicating the fact that nanotechnology is dealing with the smallest parts of matter that we can manipulate.

4. Science fiction

While there is a commonly held belief that nanotechnology is a futuristic science with applications 25 years in the future and beyond, nanotechnology is anything but science fiction. In the last 15 years over a dozen Nobel prizes have been awarded in nanotechnology, from the development of the scanning probe microscope (SPM), to the discovery of fullerenes. According to CMP Científica, over 600 companies are currently active in nanotechnology, from small venture capital backed start-ups to some of the world's largest corporations such as IBM and Samsung. Governments and corporations worldwide have ploughed over $4 billion into nanotechnology in the last year alone. Almost every university in the world has a nanotechnology department, or will have at least applied for the funding for one.

Even more significantly, there are companies applying nanotechnology to a variety of products we can already buy, such as automobile parts, clothing and ski wax. Nanotechnology is already all around us if you know where to look.

The confusion arises in part because many people in the business world do not know where to look. Over the last decade, technology has become synonymous with computers, software and communications, whether the internet or mobile telephones. Many of the initial applications of nanotechnology are materials related, such as additives for plastics, nanocarbon particles for improved steels, coatings and improved catalysts for the petrochemical industry. All of these are technology based industries, maybe not new ones, but industries with multi-billion dollar markets.

5. The nanotechnology industry

It is increasingly common to hear people referring to `the nanotechnology industry', just like the software or mobile phone industries, but will such a thing ever exist? Many of the companies working with nanotechnology are simply applying our knowledge of the nanoscale to existing industries, whether it is improved drug delivery mechanisms for the pharmaceutical industry, or producing nanoclay particles for the plastics industry. In fact nanotechnology is an enabling technology rather than an industry in its own right. No one would ever describe Microsoft or Oracle as being part of the electricity industry, even though without electricity the software industry could not exist. Rather, nanotechnology is a fundamental understanding of how nature works at the atomic scale. New industries will be generated as a result of this understanding, just as the understanding of how electrons can be moved in a conductor by applying a potential difference led to electric lighting, the telephone, computing, the internet and many other industries, all of which would not have been possible without it.

While it is possible to buy a packet of nanotechnology, a gram of nanotubes for example, it would have zero intrinsic value. The real value of the nanotubes would be in their application, whether within existing industry, or to enable the creation of a whole new one.

6. Fantastic voyage

Shrinking machines down to the size where they can be inserted into the human body in order to detect and repair diseased cells is a popular idea of the benefits of nanotechnology, and one that even comes close to reality. Many companies are already in clinical trials for drug delivery mechanisms based on nanotechnology, but unfortunately none of them involve miniature submarines. It turns out that there are a whole range of more efficient ways that nanotechnology can enable better drug delivery without resorting to the use of nanomachines.

Just the concept of navigating ones way around the body at will does not bear serious scrutiny. Imagine attempting to go against the flow in an artery—it would be like swimming upstream in a fast flowing river, while boulders the size of houses, red and white blood cells, rained down on you. Current medical applications of nanotechnology are far more likely to involve improved delivery methods, such as pulmonary or epidermal methods to avoid having to pass through the stomach, encapsulation for both delivery and delayed release, and eventually the integration of detection with delivery, in order for drugs to be delivered exactly where they are needed, thus minimizing side effects on healthy tissue and cells. As far as navigation goes, delivery will be by exactly the same method that the human body uses, going with the flow and `dropping anchor' when the drug encounters its target.

7. Shrinking stuff

Another common misconception is that nanotechnology is primarily concerned with making things smaller. This has been exacerbated by images of tiny bulls, and miniature guitars that can be strummed with the tip of an AFM, that while newsworthy, merely demonstrate our new found control of matter at the sub-micron scale. While almost the whole focus of micro-technologies has been on taking macro-scale devices such as transistors and mechanical systems and making them smaller, nanotechnology is more concerned with our ability to create from the bottom up. In electronics, there is a growing realization that with the end of the CMOS roadmap in sight at around 10 nm, combined with the uncertainly principal's limit of Von Neuman electronics at 2 nm, that merely making things smaller will not help us. Replacing CMOS transistors on a one for one basis with some type of nano device would have the effect of drastically increasing fabrication costs, while offering only a marginal improvement over current technologies.

However, nanotechnology offers us a way out of this technological and financial cul-de-sac by building devices from the bottom up. Techniques such as self assembly, perhaps assisted by templates created by nano imprint lithography, a notable European success, combined with our understanding of the workings of polymers and molecules such as Rotoxane at the nanoscale open up a whole new host of possibilities. Whether it is avoiding Moore's second law by switching to plastic electronics, or using molecular electronics, our understanding of the behaviour of materials on the scale of small molecules allows a variety of alternative approaches, to produce smarter, cheaper devices. The new understandings will also allow us to design new architectures, with the end result that functionality will become a more valid measure of performance than transistor density or operations per second.

8. Nanotechnology is new

It often comes as a surprise to learn that the Romans and Chinese were using nanoparticles thousands of years ago. Similarly, every time you light a match, fullerenes are produced. Degusssa have been producing carbon black, the substance that makes car tyres black and improves the wear resistance of the rubber, since the 1920s. Of course they were not aware that they were using nanotechnology, and as they had no control over particle size, or even any knowledge of the nanoscale they were not using nanotechnology as currently defined.

What is new about nanotechnology is our ability to not only see, and manipulate matter on the nanoscale, but our understanding of atomic scale interactions.

9. Building atom by atom

One of the defining moments in nanotechnology came in 1989 when Don Eigler used a SPM to spell out the letters IBM in xenon atoms. For the first time we could put atoms exactly where we wanted them, even if keeping them there at much above absolute zero proved to be a problem. While useful in aiding our understanding of the nanoworld, arranging atoms together one by one is unlikely to be of much use in industrial processes. Given that a Pentium 4 processor contains 42 million transistors, even simplifying the transistors to a cube of 100 atoms on each side would require 42 x 10² operations, and that is before we start to consider the other material and devices needed in a functioning processor.

Of course we already have the ability to build things atom by atom, and on a very large scale; it is called physical chemistry, and has been in industrial use for over a century producing everything from nitrates to salt. To do this, we do not need any kind of tabletop assembler as in Star Trek, usually a few barrels of readily available precursor chemicals and maybe a catalyst are all that is required.

Compare this with the difficulty of producing anything organic atom by atom, a sausage for example. Everyone is familiar with the macroscale ingredients of a sausage, some meat, maybe some fat, cartilage or other kinds of tissue, even some bone, all encased in animal gut. Never mind, argue the proponents of assemblers, things are simpler at smaller scales.

Zooming down to the microscale we still have far more complexity than we would like to attempt to replicate, with cells, cytoplasm, mitochondria, chromosomes, ribosomes and many other highly complex items of natural engineering. Moving closer to the nanoscale, we still have to deal with nucleic acids, nucleotides, peptides and proteins, none of which we fully understand, or expect to even have the computing power to understand in the near future.

In terms of return on our investment, a farmyard containing a few pigs is a far more effective sausage machine than we could ever design, and has several other by-products such as hams and a highly effective waste disposal system. This serves to illustrate just how far we are away from being able to replicate nature.

10. Attack of the killer nanobots

In terms of capturing the public imagination, unleashing hordes of self-replicating devices that escape from the lab and attack anything in their path is always going to be popular. Unfortunately nature has already beaten us to it, by several hundred million years. Naturally occurring nanomachines, that can not only replicate and mutate as they do so in order to avoid our best attempts at eradication, but can also escape their hosts and travel with alarming ease through the atmosphere. No wonder that viruses are the most successful living organisms on the planet, with most of their `machinery' being well into the nano realm. However, there are finite limits to the spread of such `nanobots', usually determined by their ability, or lack thereof, of converting a sufficiently wide range of material needed for future expansion. Indeed, the immune systems of many species, while unable to completely neutralize viruses without side effects such as runny noses, are so effective in dealing with this type of threat as a result of the wide range of different technologies available to a large complex organism when confronted with a single purpose nano-sized one. For any threat from the nano world to become a danger, it would have to include far more intelligence and flexibility than we could possibly design into it.

Our understanding of genomics and proteomics is primitive compared with that of nature, and is likely to remain that way for the foreseeable future. For anyone determined to worry about nanoscale threats to humanity should consider mutations in viruses such as HIV that would allow transmission via mosquitoes, or deadlier versions of the influenza virus, which deserve far more concern than anything nanotechnology may produce.

11. Conclusions

Nanotechnology, like any other branch of science, is primarily concerned with understanding how nature works. We have discussed how our efforts to produce devices and manipulate matter are still at a very primitive stage compared to nature. Nature has the ability to design highly energy efficient systems that operate precisely and without waste, fix only that which needs fixing, do only that which needs doing, and no more. We do not, although one day our understanding of nanoscale phenomena may allow us to replicate at least part of what nature accomplishes with ease.

While many branches of what now falls under the umbrella term nanotechnology are not new, it is the combination of existing technologies with our new found ability to observe and manipulate at the atomic scale that makes nanotechnology so compelling from scientific, business and political viewpoints.

For the scientist, advancing the sum total of human knowledge has long been the driving force behind discovery, from the gentleman scientists of the 17th and 18th centuries to our current academic infrastructure. Nanotechnology is at a very early stage in our attempts to understand the world around us, and will provide inspiration and drive for many generations of scientists.

For business, nanotechnology is no different from any other technology: it will be judged on its ability to make money. This may be in the lowering of production costs by, for example, the use of more efficient or more selective catalysts in the chemicals industry, by developing new products such as novel drug delivery mechanisms or stain resistant clothing, or the creation of entirely new markets, as the understanding of polymers did for the multi-billion euro plastics industry.

Politically, it can be argued that fear is the primary motivation. The US has opened up a commanding lead in terms of economic growth, despite recent setbacks, as a result if the growth and adoption of information technology. Of equal significance is the lead in military technology as demonstrated by the use of unmanned drones for both surveillance and assault in recent conflicts. Nanotechnology promises far more significant economic, military and cultural changes than those created by the internet, and with technology advancing so fast, and development and adoption cycles becoming shorter, playing catch-up will not be an option for governments who are not already taking action.

Maybe the greatest short term benefit of nanotechnology is in bringing together the disparate sciences, physical and biological, who due to the nature of education often have had no contact since high school. Rather than nanosubmarines or killer nanobots, the greatest legacy of nanotechnology may well prove to be the unification of scientific disciplines and the resultant ability of scientists, when faced with a problem, to call on the resources of the whole of science, not just of one discipline.

Tim Harper

About the author

Tim Harper is the Founder and President of CMP Cientifica, and the co-author of the Nanotechnology Opportunity Report^TM, described by NASA as `the defining report in the field of nanotechnology'. Tim is also the Founder and Executive Director of European NanoBusiness Association and an advisor to the US NanoBusiness Alliance. He contributes a weekly column to the Institute of Physics Nanotechweb site and writes a regular column for Tornado Insider magazine. Tim also publishes, and occasionally edits, the weekly nanotechnology newsletter TNT Weekly which has been running since 2000 and is widely read across the entire nanotechnology community, from academics to investors.

In October 2002 Time magazine described Tim as `the face of European nanotechnology' and profiled him in their Digital Europe Top 25, as one of Europe's top 25 entrepreneurs. This was followed in November by recognition in Small Times magazine who described Tim as `Europe's pre-eminent nanotech spokesman outside of government'.

Tim founded CMP Cientifica in 1997, which organizes Europe's largest scientific nanotechnology conference, TNT 200x. The company also manages both the Phantoms network, which coordinates European nanoelectronics research, and the NanoSpain network which links the Spanish scientific nanotechnology community.

Before founding CMP Cientifica, Tim was an engineer at the European Space Agency's research and development centre in Noordwijk, the Netherlands. He managed the micro- and nano-scale characterization facility, and has published extensively on analytical techniques and characterization of advanced materials.

Originally from the UK, Tim currently lives in Madrid, Spain, with his family. He has previously worked in the UK, the US, Germany, and the Netherlands.