Nanotechnology is manufacturing at the molecular level-building things from nano-scale components. Nanotechnology proposes the construction of novel nano-scale devices possessing extraordinary properties. Through the development such instruments and techniques it is becoming possible to study and manipulate individual atoms.

Nanomaterials are typically between 0.1 and 100 nanometres (nm) in size - with 1 nm being equivalent to one billionth of a metre (10^-9 m).Nanomaterials can be metals, ceramics, polymeric materials, or composite materials.Nanomaterials are midway between the scale of atomic and quantum phenomena. At the nanomaterial level, some material properties are affected by the laws of atomic physics, rather than behaving as traditional bulk materials do. Fundamental electronic, magnetic, optical, chemical, and biological processes are also different at this level.

Surface properties of material such as energy levels, electronic structure, and reactivity can be quite different from interior states, and give rise to quite different material properties. For instance, opaque substances can become transparent (copper); stable materials can turn combustible (aluminum); insoluble materials may become soluble (gold).

Using nanotechnology, materials can effectively be made to be stronger, lighter, more durable, more reactive, or better electrical conductors, among many other traits leading to reducing energy consumption, pollution, and greenhouse gas emissions; cleaner, more efficient industrial processes; remediating environmental damage; curing, managing, or preventing deadly diseases; andoffering new materials that protect against impacts, self-repair to prevent catastrophic failure, or change in ways that protect or aid soldiers on the battlefield.

Birth of Nano-technology

• The idea of nanotechnology was born in 1959 when physicist Richard Feynman gave a lecture in his talk “There's Plenty of Room at the Bottom” exploring the idea of building things at the atomic and molecular scale.
• Experimental nanotechnology came into its own in 1981, when IBM scientists in Switzerland, built the first scanning tunnelling microscope (STM).
• Now techniques have been developed to capture images at the atomic scale, these include the atomic force microscope (AFM), magnetic resonance imaging (MRI) and  modified light microscope.
• Other significant advances were made in 1985, when chemists discovered how to create a molecule of 60 carbon atoms, shaped like a soccer ball, which they called buckminsterfullerene (C60 or buckyballs). In 1991, tiny, super-strong rolls of carbon atoms known as carbon nanotubes were created. These are six times lighter, yet 100 times stronger than steel.

Both materials have important applications as nanoscale building blocks. Nanotubes have been made into fibres, long threads and fabrics, and used to create tough plastics, computer chips, toxic gas detectors, and numerous other novel materials. The far future might even see the unique properties of nanotubes harnessed to build a space elevator.

Stages in Nano Technology

• First Generation (2000-05):  Passive nano structures; materials designed to perform one task; Dispersed and contact nanostructures e.g. aerosols, colloids, Products incorporating nanostructures e.g. surface coatings, nano particles reinforced composites, nano structured metals, polymers and ceramics
• Second Generation (2005-10): introduces active nanostructures for multitasking. Bio-active, health effects e.g. targeted drugs, biodevices, Physico-chemical active; e.g. 3D transistors, amplifiers, actuators, adaptive structures
• Third Generation (2010-15): Guided assembling, 3D networking and new hierarchical architectures, robotics
• Fourth Generation (2015-20) : Molecular Nanosystmes; molecular devices ‘by design, atomic design, emerging functions.

What is nano-engineering?

• NanoEngineering is one field of nanotechnology. NanoEngineering is an interdisciplinary science that builds biochemical structures smaller than bacterium, which function like microscopic factories. This is possible by utilizing basic biochemical processes at the atomic or molecular level. In simple terms, molecules interact through natural processes, and NanoEngineering takes advantage of those processes by direct manipulation.

How are Nano materials fabricated?

• Two main approaches are used in nanotechnology.

In the "bottom-up" approach, These seek to arrange smaller components into more complex assemblies. materials and devices are built from molecular components which assemble themselves chemically by principles of molecular recognition to cause single-molecule components to automatically arrange themselves into some useful conformation. Gas phase and liquid phase methodology is also used in this process.  E.g. Aerogels, Silica Gels, DNA nanotechnology

In the "top-down" approach, (Lithographic process) nano-objects are constructed from larger entities without atomic-level control. Atomic force microscope tips can be used as a nanoscale "write head" to deposit a resist, which is then followed by an etching process to remove material in a top-down method. E.g. In semi-conductor component manufacturing.

Biomimetic approaches: Bionics or biomimicry seeks to apply biological methods and systems found in nature, to the study and design of engineering systems and modern technology. Biomineralization is one example of the systems studied.

Major Applications of nano-products

• Nanotechnology is helping to improve and revolutionize many technology and industry sectors: information technology, energy, environmental science, medicine, food safety, and transportation, among many others.
• There already exist over 1000 everyday commercial products that rely on nanoscale materials and processes:
• Nanomedicine, where functionalized polymers, hydrogels and biologics are developed as therapeutics and carriers for the controlled release and targeted delivery of therapeutics to diseased cells and organs.
• Cell and Tissue Engineering, where biomimicking materials, stem cell technology, microfluidic systems and bioimaging tools are combined to develop novel approaches to regenerative medicine and artificial organs.
• Biodevices and Diagnostics, which involve nanotechnology and microfabricated platforms for high-throughput biomarker and drug screening, automated biologics synthesis, and rapid disease diagnosis.
• Green Chemistry and Energy, which encompass the green synthesis of chemicals and pharmaceuticals, catalytic conversion of biomass, utilization of carbon dioxide, and new nanocomposite materials for energy applications.

Nano-technology in everyday use:

• Nanoscale additives in polymer composite materials can make them simultaneously lightweight, stiff, durable, and resilient. Nanoscale thin films on eyeglasses, computer and other surfaces can make them water-repellent, antireflective, self-cleaning. Nanostructured ceramic coatings exhibit much greater toughness than conventional wear-resistant coatings for machine parts
• Nanosensors built into plastic packaging can warn against spoiled food. Nanosensors are being developed to detect salmonella, pesticides, and other contaminates on food before packaging and distribution.
• Nano-engineered materials make superior household products such as environmental sensors, alert systems, air purifiers and filters; antibacterial cleansers; and specialized paints and sealing products.
• Nanoparticles are used increasingly in catalysis to boost chemical reactions. Two big applications are in petroleum refining and in automotive catalytic converters.
• Nano-engineered materials in automotive products include high-power rechargeable battery systems; thin-film smart solar panels; and fuel additives and improved catalytic converters for cleaner exhaust and extended range.

Electronics and Information Technology

• Nanoscale transistors that are smaller, faster, more powerful, and increasingly energy-efficient; soon your computer’s entire memory may be stored on a single tiny chip. Magnetic random access memory (MRAM) enabled by magnetic tunnel junctions that can save even encrypted data during a system shutdown
• Displays for many new TVs, laptop, cell phones, incorporate nano-structured polymer films OLEDs which offer brighter images, lower power consumption
• Flash memory chips for iPod nanos; conductive inks for printed electronics for RFID/smart cards; and flexible displays for e-book readers.

Carbon Nanotubes

• A Carbon Nanotube is a tube-shaped material, made of carbon, having a diameter measuring on the nanometer scale. A nanometer is one-billionth of a meter, or about one ten-thousandth of the thickness of a human hair. The graphite layer appears somewhat like a rolled-up chicken wire with a continuous unbroken hexagonal mesh and carbon molecules at the apexes of the hexagons.
• Carbon Nanotubes have many structures, differing in length, thickness, and in the type of helicity and number of layers. Although they are formed from essentially the same graphite sheet, their electrical characteristics differ depending on these variations, acting either as metals or as semiconductors.
• As a group, Carbon Nanotubes typically have diameters ranging from <1 nm up to 50 nm. Their lengths are typically several microns, but recent advancements have made the nanotubes much longer, and measured in centimeters.
• Carbon Nanotubes can be categorized by their structures:
• Single-wall Nanotubes (SWNT)
• Multi-wall Nanotubes (MWNT)
• Double-wall Nanotubes (DWNT)

Properties of a Carbon Nanotube

• The intrinsic mechanical and transport properties of Carbon Nanotubes make them the ultimate carbon fibers. The following tables (Table 1 and Table 2) compare these properties to other engineering materials.
• Overall, Carbon Nanotubes show a unique combination of stiffness, strength, and tenacity compared to other fiber materials which usually lack one or more of these properties. Thermal and electrical conductivity are also very high, and comparable to other conductive materials.

Applications for Carbon Nanotubes

• Carbon Nanotube Technology can be used for a wide range of new and existing applications: Conductive plastics, Structural composite materials , Flat-panel displays , Gas storage , Antifouling paint , Micro- and nano-electronics , Radar-absorbing coating , Technical textiles, Ultra-capacitors , Atomic Force Microscope (AFM) tips , Batteries with improved lifetime, Biosensors for harmful gases , Extra strong fibers.

Nano-biosystems, Medical, and Health Applications

• nanotechnology has the potential for improving disease diagnostics, sensing, monitoring, assessment, and treatment.
• Quantum dots are semiconducting nanocrystals offer optical detection up to 1,000 times better than conventional dyes used in many biological tests, such as MRIs. When illuminated with ultraviolet light, they emit a wide spectrum of bright colors that can be used to locate and identify specific kinds of cells and biological activitiesand render significantly more information.
• Nanoparticle serves as a platform to facilitate specific targeting of cancer cells and delivery of a potent treatment, minimizing the risk to normal tissues.
• Research enablers such as microfluidic chip-based nanolabs capable of monitoring and manipulating individual cells and nanoscale probes to track the movements of cells and individual molecules as they move about in their environments.
• Nanotechnology may prevent cancer from spreading by using sticky nanoparticles. Researchers of Cornell University (US) have designed sticky nanoparticles by attaching Trail protein and other proteins to the nanoparticles. Trail protein has the ability to kill cancer cells. These sticky nanoparticles are injected into blood stream which attaches themselves with the white blood cells. Tests revealed that as soon as sticky nanoparticles came in contact of cancel tumor cells which had broken off the main tumour and were trying to spread, it kills them. It thus prevent tumour from spreading into other regions. Sticky nanoparticles would be used before surgery or radiotherapy. This move would help in removing tumour cells from the main tumour.

Sustainable Energy Applications

• Solar panels incorporating nano technology are cheaper, more efficient and can be made in flexible rolls rather than discrete panels.
• Nanotechnology is improving the efficiency of fuel consumption efficiency in vehicles and power plants through higher-efficiency combustion and decreased friction.
• Nano-bioengineering of enzymes is aiming to enable conversion of cellulose into ethanol for fuel
• One new lithium-ion battery type uses a common, nontoxic virus in an environmentally benign production process.
• Nanostructured materials are being pursued to greatly improve hydrogen membrane and storage materials and the catalysts needed to realize fuel cells
• Researchers are developing wires containing carbon nanotubes to have much lower resistance than the high-tension wires currently used in the electric grid and thus reduce transmission power loss.
• Energy efficiency products are increasing in number and kinds of application, more efficient lighting systems

Environmental Remediation Applications

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

Nanotechnology in space

• Some of the latest avenues being explored are smart materials for the hulls composed of nanotube fibers with nano sized computers integrated into them which can flex the hull and control temperature
• Another avenue being investigated is a concept of nano robotics called "Swarms" composed of Bucky tubes in shape of cloth for astronauts which will control their involuntary movements, act as a computer and even repair itself

Another application of nano robots would be in carrying out construction projects in hostile environments with less investment of resources and a lot less danger to human explorers.

Molecular machines

The Nobel Prize in Chemistry 2016 is awarded to Jean-Pierre Sauvage, Sir J. Fraser Stoddart and Bernard L. Feringa for their development of molecular machines that are a thousand times thinner than a hair strand.

A molecular machine, or nanomachine, is any discrete number of molecular components that produce quasi-mechanical movements (output) in response to specific stimuli (input).

How molecules became machines

The journey begins with the question: How small can you make machinery? This is the question that Nobel Laureate Richard Feynman (famed for his 1950s’ predictions of developments in nanotechnology) posed at the start of a visionary lecture in 1984.

One possible way would be to build a pair of mechanical hands that are smaller than your own, which in turn build a pair of smaller hands, which build even smaller hands, and so on, until a pair of miniscule hands can build equally miniscule machinery. This has been tried, said Feynman, but without great success.

Another strategy, in which Richard Feynman had more faith, would be to build the machinery from the bottom up. Nanotechnology - the creation of structures on the scale of a nanometer, or a billionth of a meter - has been a field of fruitful research for a couple of decades. In this next wave of research, scientists are learning how to construct tiny moving machines, about one-thousandth the width of a strand of human hair.

Taking this research forward, a breakthrough was achieved in 1983 by Sauvage.Hesucceeded in producing two ring-shaped molecules linked by an easily manipulated mechanical bond. This was the first time chemists had manufactured a molecule that could be manipulated in this way.

In 1991, Stoddart reinvented the wheel on a microscopic scale.The machine was eventually used to build a “molecular abacus” that could store information.

Feringa built on both of these breakthroughs to create the world's first molecular motor, a tiny spinning blade that rotates continually on an axis, in 1999. That molecule was developed into a “nanocar,” whose four wheels rotate to move the microscopic structure forward along a plane, like a minuscule car with four-wheel drive. Feringa also showed that the molecule could be used to rotate a glass rod thousands of times larger than the motor itself.

Classification of Molecular machines:

Molecular machines can be divided into two broad categories: synthetic and biological.

Synthetic machines: Operating on a scale a thousand times as small as the width of a human hair, these “machines” are specially designed molecules with movable parts that produce controlled movements when energy is added.

Examples of synthetic molecular machines

i) Molecular motors are molecules that are capable of unidirectional rotation motion powered by external energy input. A number of molecular machines have been synthesized powered by light or reaction with other molecules.

ii) A molecular switch is a molecule that can be reversibly shifted between two or more stable states. The molecules may be shifted between the states in response to changes in e.g. pH, light, temperature, an electric current.

iii) Molecular tweezers are host molecules capable of holding items between its two arms. The open cavity of the molecular tweezers binds items using non-covalent bonding including hydrogen bonding, metal coordination, hydrophobic forces, van der Waals forces, π-π interactions, and/or electrostatic effects. Examples of molecular tweezers have been reported that are constructed from DNA and are considered DNA machines.

The construction of more complex molecular machines is an active area of theoretical research. Whereas biology has perfected its machines over billions of years of evolution, chemists keen to imitate these structures are just getting started.

Biological molecular machines: Biology uses molecules for absolutely everything – from harvesting energy from the sun to the way that we see. The proteins are the most complicated biological molecules. Scientists have taken to calling them machines because, just like those designed by humans, they produce mechanical motion in response to an input, allowing them to perform a task.

Example of biological molecular machines

The most complex molecular machines are proteins found within cells.

These include motor proteins, such as: 

i)Myosin, which is responsible for muscle contraction.

ii)Kinesin moves cargo inside the cell away from the nucleus along microtubes,

iii)Dynein produces the axonemal beating of motile cilia and flagella.

These proteins and their nanoscale dynamics are far more complex than any molecular machines that have yet been artificially constructed.

Potential:

Compared with the machines that changed our world following the industrial revolution of the nineteenth century, molecular machinery is still in a phase of growth. However, just as the world stood perplexed before the early machines, such as the first electric motors and steam engines, there is the potential for a similar explosive development of molecular machines. In a sense, we are at the dawn of a new industrial revolution of the twenty-first century, and the future will show how molecular machinery can become an integral part of our lives.

 They could one day go to work in the human body:Chemists hope that one day these mini machines could be developed so they can deliver drugs within the human body directly to cancerous cells or target a specific area of tissue to medicate. When it’s perfected, this method should greatly reduce the damage treatment such as chemotherapy does to a patient’s healthy cells.

They could even detect disease before it show any symptoms:
Recent research into molecular machines has suggested that as well as killing cancer cells or transporting molecules for medical reasons, they could one day lead to the design of a molecular computer which could be placed inside the body to detect disease before any symptoms are exhibited.

They may one day be used to build new materials, operate microscopic sensors and create energy-storage mechanisms too tiny to be seen with the naked eye. Some labs have already succeeded in using molecular machines to produce tiny peptide assembly lines and more-resilient plastics (including a film that can endure being beaten by a hammer).

Nanotechnology in India

"Understanding the immense potential of nanotechnology and its wide ranging applications to benefit common people, DIT  initiated the Nanotechnology Development Programme in 2004, through which it plans to create R & D capacity and infrastructure in nanoelectronics at national level. The emphasis is on small and medium level research projects in specific areas of nanoelectronics such as nanomaterials, nanodevices, carbon nanotubes (CNT), nanosystems, nanometrology, et al.”

• Nanoscience & Technology Initiative 2002-2006-Rs 350 Crores
• 2007-Launch of Nanotechnology Mission- $200 million under Department of Science & Technology
• R&D is being done in autonomous Institutions, CSIR labs, Universities
• DBT major funder in health related nanotechnology, energy, water, agriculture and studies on toxicity have been funded First phase basic science funded
• Private sector R&D minimal- mostly in pharmaceuticals, consumer goods (water filters)
• Right now there is no regulatory framework – so existing laws like EPA, Factories Act, Drugs &Cosmetics Act are applicable.
• The Kochi-based Amrita Centre for Nanosciences and Molecular Medicine on 22 September 2013 announced it’s newly developed a nano-medicine for drug-resistant blood cancer. This invention expected to dramatically improve the treatment of drug-resistant Chronic Myelogenous Leukemia (CML), when used in combination with Imatinib, the standard drug for the disease.
• In another significant invention, the institute has devised a mechanism that can effectively prevent recurrence of glioma or brain tumour. This deadly disease affects about four out of every 100000 people in India. The life expectancy of high-grade glioma patients is about one to two years.
• Chronic Myelogenous Leukemia (a form of blood cancer) annually affects approximately two out of every 100000 Indians. Almost 40 per cent of these cases are resistant to Imatinib. For such patients, treatment options are extremely limited.

Concerns about Nanotechnology

• Properties of nanoscale materials (e.g., small size, high surface area-to-volume ratio) have given rise to have also given rise to concerns about their potential adverse implications for the environment, and human health and safety. The areas of concerns are in protecting the health and safety of workers, consumers & general public who may be exposed to nanoparticles, as well as in understanding the environmental impact of manufacturing processes and the use and disposal of nanotechnology products.
• Stakeholders have identified areas: toxicity of nanoscale materials; developing methods for assessing and managing the risks of these materials; and understanding how these materials move in, and interact with, the environment.
• The weapons of the nano generation will not only be much smaller than today’s but much deadlier.
• Then there are other concerns too: the possibility of deliberate abuse. While the development of nanotechnology is, likely to take a few decades, and the early developers are likely to be large organizations with major resources that can afford substantial development efforts, in the long run nanotechnology is going to be available to a wider range of groups – including terrorist organizations and others of malign intent.

Nano grapheme

• An international team of researchers has developed a novel way to produce graphene nanoribbons that enables electrons to travel though it without resistance at room temperature, a property known as ballistic transport. The ballistic transport properties measured by the researchers exceeds previous theoretical limits for graphene by a factor of ten, opening up the potential in the opinion of the researchers for graphene to usher in a new era in electronics despite the material's lack of a band gap. When they measured their results, they discovered that the graphene nanoribbons behaves more like an optical waveguide and allows electrons to flow smoothly along the edges of the material. The result is that in 40 nm-wide graphene nanoribbons ballistic transport exceeded the theoretical conductance levels of graphene by a factor of 10.

The scope and application – in brief

• Improving the ability to control matter has long been a major aim of technology.
• The equivalent of a modern main frame computer could fit into a cubic micron, a volume for smaller than that of a single human cell. A laptop computer could then have more power than all the computers in the world today put together.
• The demand for environmentally sustainable industrial, agricultural, aquacultural and silvicultural technologies is bringing about a shift from chemical based solutions to biological based ones.
• Nanotechnology holds the answer to the water shortage in the world. The recent discovery of Nano-Graphene Sieve can make sea waterdrinkable.
• Nanotechnology will let us build fleets of computer controlled molecular tools (called nanobots or cell machines) much smaller than a human cell and built with the accuracy and precision of drug molecules.
• Nanotechnology has the potential of making our environment cleaner. For instance, if you make a plastic with nanotechnology, you can feed stocks of pure elements like carbon, hydrogen and oxygen and force individual atoms deliberately into chemical bonds without intermediate steps that produce all those environmentally unfriendly waste products.
• Higher crop yields could be achieved by intensive green house agriculture. Plants growing in controlled environments (with optimal temperature, CO₂, water, nutrients etc) can grow year round and produce an order of magnitude more food per acre than existing methods.
• Rather than felling forests to make paper, we’d have assemblers synthesizing paper. Rather than using oil for energy, we’d have molecule-sized solar cells mixed into road pavement. With such solar nanocells, a sunny patch of pavement a few hundred square miles could generate enough energy for a country the size of India.
• Space transportation costs could be reduced considerably with nano-technology. Comparing structural components made from titanium versus a diamonded composite material, it is estimated that single stage to orbit transportation costs would drop in one scenario) from $ 16, 000/ kg to $3.54/kg.