Applied Sciences

Micro/Nanotechnology


NANOTECHNOLOGY: DEFINED AND DESCRIBED

Nanotechnology (sometimes shortened to "nanotech") is the study of manipulating matter on an atomic and molecular scale. Generally, nanotechnology deals with developing materials, devices, or other structures possessing at least one dimension sized from 1 to 100 nanometres. Quantum mechanical effects are important at this quantum-realm scale. It is considered a key technology for the future and various governments have invested billions of dollars in its future. The USA has invested 3.7 billion dollars through its National Nanotechnology Initiative followed by Japan with 750 million and the European Union 1.2 billion.

Nanotechnology is very diverse, ranging from extensions of conventional device physics to completely new approaches based upon molecular self-assembly, from developing new materials with dimensions on the nanoscale to direct control of matter on the atomic scale. Nanotechnology entails the application of fields of science as diverse as surface science, organic chemistry, molecular biology, semiconductor physics, microfabrication, etc.

There is much debate on the future implications of nanotechnology. Nanotechnology may be able to create many new materials and devices with a vast range of applications, such as in: medicine, electronics, biomaterials and energy production. On the other hand, nanotechnology raises many of the same issues as any new technology, including concerns about the toxicity and environmental impact of nanomaterials, and their potential effects on global economics, as well as speculation about various doomsday scenarios. These concerns have led to a debate among advocacy groups and governments on whether special regulation of nanotechnology is warranted.


HISTORY OF NANOTECHNOLOGY

Part 1:

Although nanotechnology is a relatively recent development in scientific research, the development of its central concepts happened over a longer period of time. The emergence of nanotechnology in the 1980s was caused by the convergence of experimental advances such as the invention of the scanning tunneling microscope in 1981 and the discovery of fullerenes in 1985, with the elucidation & popularization of a conceptual framework for the goals of nanotechnology beginning with the 1986 publication of the book Engines of Creation. The scanning tunneling microscope, an instrument for imaging surfaces at the atomic level, was developed in 1981 by Gerd Binnig and Heinrich Rohrer at IBM Zurich Research Laboratory, for which they received the Nobel Prize in Physics in 1986. Fullerenes were discovered in 1985 by Harry Kroto, Richard Smalley, and Robert Curl, who together won the 1996 Nobel Prize in Chemistry.

Around the same time, K. Eric Drexler developed and popularized the concept of nanotechnology & founded the field of molecular nanotechnology. In 1979, Drexler encountered Richard Feynman's 1959 talk "There's Plenty of Room at the Bottom". The term "nanotechnology", originally coined by Norio Taniguchi in 1974, was unknowingly appropriated by Drexler in his 1986 book Engines of Creation: The Coming Era of Nanotechnology. In this book Drexler proposed the idea of a nanoscale "assembler" which would be able to build a copy of itself, and of other items of arbitrary complexity. He also first published the term "grey goo" to describe what might happen if a hypothetical self-replicating molecular nanotechnology went out of control. Drexler's vision of nanotechnology is often called "Molecular Nanotechnology" (MNT) or "molecular manufacturing."  Drexler at one point proposed the term "zettatech" which never became popular.

Part 2:

In the early 2000s, the field was subject to growing public awareness and controversy with prominent debates about both its potential implications, exemplified by the Royal Society's report on nanotechnology, as well as the feasibility of the applications envisioned by advocates of molecular nanotechnology. This culminated in the public debate between Eric Drexler and Richard Smalley in 2001 and 2003. Governments moved to promote and fund research into nanotechnology with programs such as the National Nanotechnology Initiative. The early 2000s also saw the beginnings of commercial applications of nanotechnology, although these were limited to bulk applications of nanomaterials. The following are examples of such bulk applications: the Silver Nano platform for using silver nanoparticles as an antibacterial agent, nanoparticle-based transparent sunscreens, and carbon nanotubes for stain-resistant textiles.

Drexler's book Engines of Creation: The Coming Era of Nanotechnology was published nearly 30 years ago far back in 1986. For a detailed outline of his book go to: http://e-drexler.com/d/06/00/EOC/EOC_Table_of_Contents.html


FUNDAMENTAL CONCEPTS OF NANOTECHNOLOGY

Nanotechnology is the engineering of functional systems at the molecular scale. This covers both current work and concepts that are more advanced. In its original sense, nanotechnology refers to the projected ability to construct items from the bottom up, using techniques and tools being developed today to make complete, high performance products.

One nanometer (nm) is one billionth, or 10−9, of a meter. By comparison, typical carbon-carbon bond lengths, or the spacing between these atoms in a molecule, are in the range 0.12–0.15 nm, and a DNA double-helix has a diameter around 2 nm. On the other hand, the smallest cellular life-forms, the bacteria of the genus Mycoplasma, are around 200 nm in length. By convention, nanotechnology is taken as the scale range 1 to 100 nm following the definition used by the National Nanotechnology Initiative in the US. The lower limit is set by the size of atoms (hydrogen has the smallest atoms, which are approximately a quarter of a nm diameter) since nanotechnology must build its devices from atoms and molecules. The upper limit is more or less arbitrary but is around the size that phenomena not observed in larger structures start to become apparent and can be made use of in the nano device. These new phenomena make nanotechnology distinct from devices which are merely miniaturised versions of an equivalent macroscopic device; such devices are on a larger scale and come under the description of microtechnology.

To put that scale in another context, the comparative size of a nanometer to a meter is the same as that of a marble to the size of the earth. Or another way of putting it: a nanometer is the amount an average man's beard grows in the time it takes him to raise the razor to his face. Two main approaches are used in nanotechnology. In the "bottom-up" approach, materials and devices are built from molecular components which assemble themselves chemically by principles of molecular recognition. In the "top-down" approach, nano-objects are constructed from larger entities without atomic-level control. Areas of physics such as nanoelectronics, nanomechanics, nanophotonics and nanoionics have evolved during the last few decades to provide a basic scientific foundation of nanotechnology.


THE REVOLUTION DUE TO NANOTECHNOLOGY

Nanotechnology is revolutionising modern science, yet the public has little understanding of its ethical implications. Nanoethics: Big Ethical Issues with Small Technology, by Donal P. O’Mathuna was reviewed recently in the London Review of Books. The book explores the philosophy behind this hugely topical contemporary debate. Nanotechnology manipulates matter at the atomic level. It leads to innovative processes and products that are revolutionizing many areas of modern life. Huge amounts of public funds are being invested in the science, yet the public has little understanding of the technology or its ethical implications. Indeed, the ethical, social and political dimensions of nanotechnology are only beginning to receive the attention they require – outside of science fiction contexts.

Surveillance devices may become so small that they are practically invisible to the naked eye, raising concerns about privacy. Nanomedicine may lead to the development of new diagnostic and therapeutic devices, yet anxieties have been raised about the impact of ‘nanobots’ circulating in our bodies. Military applications, or misuses, of nanotechnology raise other concerns. This book explores in an accessible and informative way how nanotechnology is likely to impact the lives of ordinary people in the coming years and why ethical reflection on nanotechnology is needed now. Articulate, provocative and stimulating, this timely book will make a significant contribution to one of the most important debates of our time. “Think Now” is a new series of books which examines central contemporary social and political issues from a philosophical perspective. These books aim to be accessible, rather than overly technical, bringing philosophical rigour to modern questions which matter the most to us. Provocative yet engaging, the authors take a stand on political and cultural themes of interest to any intelligent reader.

NANOCHEMISTRY

Nanochemistry or Nanotechnology related with the production and the reactions of nanoparticles and their compounds. It is concerned with the unique properties associated with assemblies of atoms or molecules on a scale between that of the individual building blocks and the bulk material (from 1 to 1000 nm), At this level, quantum effects can be significant, and also new ways of carrying out chemical reactions become possible. Go to these two links for more: http://www.chemicalforums.com/index.php?board=63.0 and http://en.wikipedia.org/wiki/Nanochemistry

NANOIMPRINT

Part 1:

The two main categories of nanoimprint thermal nanoimprint, also called hot-embossing, and UV-nanoimprint. While there are many different flavours of nanoimprint processes, these are the two main ones. Thermal nanoimprint has been the first kind of nanoimprint process ever used and the original one adopted by Prof. Chuo back in 1996. The thermal nanoimprint process is very easy to understand and straightforward. It is as follows: a layer of thermoplastic polymer is deposited on the surface of the substrate by spin coating or alternative method; then the substrate is placed inside the imprint machine along with the mold and the mold is pressed against the substrate at a set pressure. The substrate received a precise amount of heat from the machine and the temperature of the polymer rises over the glass-transition temperature and becoming soft.

Part 2:

The mold is kept pressed against the substrate for an amount of time, after that the substrate is cooled down and the mold is released
After the pattern is transferred to the mold polymer layer, it is then transferred to the beneath silicon substrate surface by etching process
UV-nanoimprint process is different from thermal nanoimprint in two aspects: it does not use heat to soften the polymer layer but UV light and requires a UV-transparent mold. For more details go to:http://www.martini-tech.com/the-two-main-categories-of-nanoimprint/#comment-3

LARGER TO SMALLER: A MATERIALS PERSPECTIVE

A number of physical phenomena become pronounced as the size of the system decreases. These include statistical mechanical effects, as well as quantum mechanical effects, for example the “quantum size effect” where the electronic properties of solids are altered with great reductions in particle size. This effect does not come into play by going from macro to micro dimensions. However, quantum effects become dominant when the nanometer size range is reached, typically at distances of 100 nanometers or less, the so called quantum realm. Additionally, a number of physical (mechanical, electrical, optical, etc.) properties change when compared to macroscopic systems. One example is the increase in surface area to volume ratio altering mechanical, thermal and catalytic properties of materials. Diffusion and reactions at nanoscale, nanostructures materials and nanodevices with fast ion transport are generally referred to nanoionics. Mechanical properties of nanosystems are of interest in the nanomechanics research. The catalytic activity of nanomaterials also opens potential risks in their interaction with biomaterials.

Materials reduced to the nanoscale can show different properties compared to what they exhibit on a macroscale, enabling unique applications. For instance, opaque substances become transparent (copper); stable materials turn combustible (aluminum); insoluble materials become soluble (gold). A material such as gold, which is chemically inert at normal scales, can serve as a potent chemical catalyst at nanoscales. Much of the fascination with nanotechnology stems from these quantum and surface phenomena that matter exhibits at the nanoscale.


SIMPLE TO COMPLEX: A MOLECULAR PERSPECTIVE

Modern synthetic chemistry has reached the point where it is possible to prepare small molecules to almost any structure. These methods are used today to manufacture a wide variety of useful chemicals such as pharmaceuticals or commercial polymers. This ability raises the question of extending this kind of control to the next-larger level, seeking methods to assemble these single molecules into supramolecular assemblies consisting of many molecules arranged in a well defined manner.

These approaches utilize the concepts of molecular self-assembly and/or supramolecular chemistry to automatically arrange themselves into some useful conformation through a bottom-up approach. The concept of molecular recognition is especially important: molecules can be designed so that a specific configuration or arrangement is favored due to non-covalent intermolecular forces. The Watson–Crick basepairing rules are a direct result of this, as is the specificity of an enzyme being targeted to a single substrate, or the specific folding of the protein itself. Thus, two or more components can be designed to be complementary and mutually attractive so that they make a more complex and useful whole.

Such bottom-up approaches should be capable of producing devices in parallel and be much cheaper than top-down methods, but could potentially be overwhelmed as the size and complexity of the desired assembly increases. Most useful structures require complex and thermodynamically unlikely arrangements of atoms. Nevertheless, there are many examples of self-assembly based on molecular recognition in biology, most notably Watson–Crick basepairing and enzyme-substrate interactions. The challenge for nanotechnology is whether these principles can be used to engineer new constructs in addition to natural ones.

MOLECULAR GASTRONOMY

Molecular gastronomy is a subdiscipline of food science that seeks to investigate the physical and chemical transformations of ingredients that occur in cooking. Its program includes three axes, as cooking was recognized to have three components, which are social, artistic and technical. Molecular cuisine is a modern style of cooking, and takes advantage of many technical innovations from the scientific disciplines. The term "molecular gastronomy" was coined in 1988 by late Oxford physicist Nicholas Kurti & the French INRAchemist Hervé This. Some chefs associated with the term choose to reject its use, preferring other terms such as multi sensory cooking, modernist cuisine, culinary physics, and experimental cuisine. For more information go to: http://en.wikipedia.org/wiki/Molecular_gastronomy

MOLECULAR NANOTECHNOLOGY: A LONG TERM VIEW

Part 1:

Molecular nanotechnology, sometimes called molecular manufacturing, describes engineered nanosystems (nanoscale machines) operating on the molecular scale. Molecular nanotechnology is especially associated with the molecular assembler, a machine that can produce a desired structure or device atom-by-atom using the principles of mechanosynthesis. Manufacturing in the context of productive nanosystems is not related to, and should be clearly distinguished from, the conventional technologies used to manufacture nanomaterials such as carbon nanotubes and nanoparticles.

When the term "nanotechnology" was independently coined and popularized by Eric Drexler (who at the time was unaware of an earlier usage by Norio Taniguchi) it referred to a future manufacturing technology based on molecular machine systems. The premise was that molecular scale biological analogies of traditional machine components demonstrated molecular machines were possible: by the countless examples found in biology, it is known that sophisticated, stochastically optimised biological machines can be produced.

It is hoped that developments in nanotechnology will make possible their construction by some other means, perhaps using biomimetic principles. However, Drexler and other researchers have proposed that advanced nanotechnology, although perhaps initially implemented by biomimetic means, ultimately could be based on mechanical engineering principles, namely, a manufacturing technology based on the mechanical functionality of these components (such as gears, bearings, motors, and structural members) that would enable programmable, positional assembly to atomic specification. The physics and engineering performance of exemplar designs were analyzed in Drexler's book Nanosystems.

Part 2:

In general it is very difficult to assemble devices on the atomic scale, as all one has to position atoms on other atoms of comparable size and stickiness. Another view, put forth by Carlo Montemagno, is that future nanosystems will be hybrids of silicon technology and biological molecular machines. Yet another view, put forward by the late Richard Smalley, is that mechanosynthesis is impossible due to the difficulties in mechanically manipulating individual molecules.

This led to an exchange of letters in the ACS publication Chemical & Engineering News in 2003. Though biology clearly demonstrates that molecular machine systems are possible, non-biological molecular machines are today only in their infancy. Leaders in research on non-biological molecular machines are Dr. Alex Zettl and his colleagues at Lawrence Berkeley Laboratories and UC Berkeley. They have constructed at least three distinct molecular devices whose motion is controlled from the desktop with changing voltage: a nanotube nanomotor, a molecular actuator, and a nanoelectromechanical relaxation oscillator. See nanotube nanomotor for more examples.

An experiment indicating that positional molecular assembly is possible was performed by Ho and Lee at Cornell University in 1999. They used a scanning tunneling microscope to move an individual carbon monoxide molecule (CO) to an individual iron atom (Fe) sitting on a flat silver crystal, and chemically bound the CO to the Fe by applying a voltage.

NANOTECHNOLOGY AND MEDICINE

Part 1:

The following article "Nanotechnology In Medicine: Huge Potential, But What Are The Risks?"  appeared on 4 May 2012, in the online journal-newsletter Medical News Today. This electronic medical news source was launched in 2003 to help medical health professionals and members of the public stay up-to-date with the latest medical and health news.  The article began as follows: "the manipulation of matter at the atomic and molecular scale to create materials with remarkably varied and new properties, is a rapidly expanding area of research with huge potential in many sectors, ranging from healthcare to construction and electronics. In medicine, it promises to revolutionize drug delivery, gene therapy, diagnostics, and many areas of research, development and clinical application. This article does not attempt to cover the whole field, but offers, by means of some examples, a few insights into how nanotechnology has the potential to change medicine, both in the research lab and clinically, while touching on some of the challenges and concerns that it raises."

"What is Nanotechnology?The prefix "nano" stems from the ancient Greek for "dwarf". In science it means one billionth (10 to the minus 9) of something, thus a nanometer (nm) is is one billionth of a meter, or 0.000000001 meters. A nanometer is about three to five atoms wide, or some 40,000 times smaller than the thickness of human hair. A virus is typically 100 nm in size.  The ability to manipulate structures and properties at the nanoscale in medicine is like having a sub-microscopic lab bench on which you can handle cell components, viruses or pieces of DNA, using a range of tiny tools, robots and tubes."

Part 2:

Manipulating DNATherapies that involve the manipulation of individual genes, or the molecular pathways that influence their expression, are increasingly being investigated as an option for treating diseases. One highly sought goal in this field is the ability to tailor treatments according to the genetic make-up of individual patients. This creates a need for tools that help scientists experiment and develop such treatments.  Imagine, for example, being able to stretch out a section of DNA like a strand of spaghetti, so you can examine or operate on it, or building nanorobots that can "walk" and carry out repairs inside cell components. Nanotechnology is bringing that scientific dream closer to reality.  For instance, scientists at the Australian National University have managed to attach coated latex beads to the ends of modified DNA, and then using an "optical trap" comprising a focused beam of light to hold the beads in place, they have stretched out the DNA strand in order to study the interactions of specific binding proteins. Meanwhile chemists at New York University (NYU) have created a nanoscale robot from DNA fragments that walks on two legs just 10 nm long. In a 2004 paper published in the journal Nano Letters, they describe how their "nanowalker", with the help of psoralen molecules attached to the ends of its feet, takes its first baby steps: two forward and two back.

One of the researchers, Ned Seeman, said he envisages it will be possible to create a molecule-scale production line, where you move a molecule along till the right location is reached, and a nanobot does a bit chemisty on it, rather like "spot-welding" on a car assembly line. Seeman's lab at NYU is also looking to use DNA nanotechnology to make a biochip computer, and to find out how biological molecules crystallize, an area that is currently fraught with challenges. The work that Seeman and colleagues are doing is a good example of "biomimetics", where with nanotechnology they can imitate some of the biological processes in nature, such as the behavior of DNA, to engineer new methods and perhaps even improve them.

DNA-based nanobots are also being created to target cancer cells. For instance, researchers at Harvard Medical School in the US reported recently in Science how they made an "origami nanorobot" out of DNA to transport a molecular payload. The barrel-shaped nanobot can carry molecules containing instructions that make cells behave in a particular way. In their study, the team successfully demonstrates how it delivered molecules that trigger cell suicide in leukemia and lymphoma cells. For more on this topic go to: http://www.medicalnewstoday.com/articles/244972.php

Nanobots made from other materials are also in development. For instance, gold is the material scientists at Northwestern University use to make "nanostars", simple, specialized, star-shaped nanoparticles that can deliver drugs directly to the nuclei of cancer cells. In a recent paper in the journal ACS Nano, they describe how drug-loaded nanostars behave like tiny hitchhikers, that after being attracted to an over-expressed protein on the surface of human cervical and ovarian cancer cells, deposit their payload right into the nuclei of those cells. The researchers found giving their nanobot the shape of a star helped to overcome one of the challenges of using nanoparticles to deliver drugs: how to release the drugs precisely. They say the shape helps to concentrate the light pulses used to release the drugs precisely at the points of the star. 

 NATIONAL ENABLING TECHNOLOGIES STRATEGY

On 13 May 2009 the Australian Government announced the four year National Enabling Technologies Strategy (NETS) to provide a framework for the responsible development of enabling technologies such as nanotechnology and other new technologies as they emerge in Australia. Responsibility for implementing the Strategy rests with three areas of the Department: the National Measurement Institute (NMI); the Enabling Technologies Public Awareness and Community Engagement (PACE) Section and the Enabling Technologies Policy (ETP) Section.

The ETP Section provides policy coordination, facilitates uptake of enabling technologies, and provides secretariat services to several committees linked to NETS. The PACE Section seeks to increase the public's awareness, knowledge and understanding of  enabling technologies, including the risks and the benefits, to enable a more informed public debate. Go to this link for more info:  http://www.innovation.gov.au/INDUSTRY/NANOTECHNOLOGY/Pages/default.aspx

NANOTECHNOLOGY

There is a special issue to celebrate the 25th volume of Nanotechnology which was the world's first academic journal in nanoscale science and technology. The collection of articles in this special issue presents a slice of the field as it is now, including research at the forefront of the different disciplines comprising the journal's scope. The journal Nanotechnology speaks to Professor Christoph Gerber, Professor Franz Gießibl, and Professor James K Gimzewski about the field of nanotechnology as the journal is about to embark on its 25th volume. Go to this link for nano-discussion podcasts: http://iopscience.iop.org/0957-4484  Nanotechnology is an electronic journal which encompasses the understanding of the fundamental physics, chemistry, biology and the technology of nanometre-scale objects. The latest issue is January 2014 and it is found at this link: http://iopscience.iop.org/0957-4484/25/2

CTHEORY.NET

C.Theory.net
is an international journal of theory, technology and culture. It publishes articles, interviews, event-scenes and reviews of key books. The following review "Fractured Flesh" is a discussion of the book: Terminal Identity: The Virtual Subject in Post-Modern Science Fiction, (Durham: Duke University Press, 1993).  The book is by Scott Bukatman. The content of Bukatman's piece of sci-fi has a tangential connection with nanotechnology, and so I include it here.  The review opens: "the entire planet is being developed into terminal identity and complete surrender." Terminal identity - the birth of a new subjectivity at the interface of the body and computer/TV screen. Within technology's increasing pervasion of conceptions of the self comes a belief that individualism can merge with technology, and current notions of humanity can be retained."

Scott Bukatman is a cultural theorist and Professor of Film and Media Studies at Stanford University. Bukatman's research examines how popular media like film and comics, as well as genres like: science fiction, musicals, superhero narratives "mediate between new technologies and human perceptual and bodily experience."  Bukatman argues that the line between pomo academics and Science Fiction(SF) has become exceedingly blurred. He interweaves the "science fictions" of French sociologist Jean Baudrillard, feminist Donny Haraway, and Guy Debord, with those of Gibson, Ballard and Dick. He asserts that narrative form gives way to spatialized concerns that engage our fixation with the distances, spaces and proximities between embodied humanity and the electronic machines. These machines were invented to facilitate an individuated subjectivity and global capital flows. SF addresses how technology infects our being in the world, constructing "a space of accommodation to an intensely technological existence."  SF is the prescient mind that has first imagined the virtual world now under contract to be built. For more go to:http://www.ctheory.net/articles.aspx?id=269

JOURNAL FOR NANOTECHNOLOGY

Go to this link:https://sites.google.com/site/photonfoundationorganization/home/the-journal-for-nanotechnology