Concepts of Nanotechnology


Concepts of Nanotechnology at on April 01, 2014

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Professor Dr. Md. Sultan Mahmud

Nanotechnology is the manipulation of matter on an atomic, molecular, and supramolecular scale. The nanotechnology has its roots date back to a 1959 talk given by Richard Feynman (http:/ in which he said, “The principles of Physics, as far as I can see, do not speak against the possibility of maneuvering things atom by atom. It is not an attempt to violate any laws; it is something in principle, that can be done; but in practice it has not been done because we are too big”. 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. Nanotechnology today is growing very rapidly and has infinite applications in almost everything we do. The medicine we take, food we eat, chemicals we use, car we drive and much much more. For example, the invention of the scanning tunneling microscope in 1981 provided unprecedented visualization of individual atoms and bonds, and was successfully used to manipulate individual atoms in 1989. The microscope’s developers Gerd Binnig and Heinrich Rohrer at IBM Zurich Research Laboratory received a Nobel Prize in Physics in 1986. Binnig, Quate and Gerber also invented the analogous atomic force microscope that year.

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.

Several 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 can become significant 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.

Meanwhile, commercialization of products based on advancements in nanoscale technologies began emerging. These products are limited to bulk applications of nanomaterials and do not involve atomic control of matter. Some examples include the Silver Nano platform for using silver nanoparticles as an antibacterial agent, nanoparticle-based transparent sunscreens, and carbon nanotubes for stain-resistant textiles.

MKnano offers large variety of nano products in various forms as mentioned below.

Material Formats:

Atomic & Molecular Clusters, Buckyballs & Fullerenes, Bulk Nanostructured Metals, Magnetic Nanoparticles / Magnetic Nanostructures, Nanobelts, Nanolubricant Powders, Nanocrystals & Nanopowders, NanoFillers / NanoAdditives, Nanoparticles / Nanopowders, Nanoparticle Dispersions, Nanorods, Nanosponge Abrasives, Nano Tubes, Nanowires, Quantum Dots / Nano Dots, Reactive Electro Exploded Nano Powders.

Carbon Nanotubes:

Single wall (SWNT), Double wall (DWNT), Multiwall (MWNT), (alligned/tangled/dispersable), OH, COOH Functionalized SWNT/MWNT, Industrial Grade SWCNTs, MWCNTs, Conducting (Metallic) and Semiconducting SWCNTs, MWCNT Nonwoven Papers, CNT Foam, Special application CNTs. Other Nanotubes (Metals, Compounds, and Oxides/Hyroxides)

Quantum Dots:

Cadmium Mercury Telluride (CdHgTe), Cadmium Selenide (CdSe), Cadmium Selenide/Zinc Sulfide (CdSe/ZnS), Cadmium Sulfide (CdS), Cadmium Telluride (CdTe), Cadmium Telluride/Cadmium Sulfide (CdTe/CdS), Lead Selenide (PbSe), Lead Sulfide (PbS)

Nano Dry Lubricant Powders:

Tungsten Disulfide (WS2), Molybdenum Disulfide (MoS2), Hex-Boron Nitride (hBN), Graphite

Specially formulated Nano Lubricant Additive Powders to improve lubricity and save energy.

Materials reduced to the nanoscale can show different properties compared to what they exhibit on a macroscale, enabling unique applications. For instance, opaque substances can become transparent (copper); stable materials can turn combustible (aluminum); insoluble materials may 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.

Professor Dr.Md.Sultan Mahmud
Professor of Physics & Head
Department of Basic Sciences & Humanities
University of Asia Pacific

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Nanotechnology in food and agriculture at on April 02, 2014

2 Apr 2014   05:52:28 PM   Wednesday BdST this

Nanotechnology in food and agriculture

Dr. Md. Sultan Mahmud

The current global population is nearly 6 billion with 50% living in Asia. A large proportion of those living in developing countries face daily food shortages as a result of environmental impacts or political instability, while in the developed world there is a food surplus.

For developing countries the drive is to develop drought and pest resistant crops, which also maximize yield. 

In developed countries, the food industry is driven by consumer demand which is currently for fresher and healthier foodstuffs. This is big business, for example the food industry in the UK is booming with an annual growth rate of 5.2% and the demand for fresh food has increased by 10% in the last few years. 

The potential of nanotechnology to revolutionise the health care, textile, materials, information and communication technology, and energy sectors has been well-publicised. In fact several products enabled by nanotechnology are already in the market, such as antibacterial dressings, transparent sunscreen lotions, stain-resistant fabrics, scratch free paints for cars, and self cleaning windows.

The applications of nanotechnology to the agricultural and food industries were first addressed by a United States Department of Agriculture roadmap published in September 2003. The prediction is that nanotechnology will transform the entire food industry, changing the way food is produced, processed, packaged, transported, and consumed.

The EU’s vision is of a “knowledge-based economy” and as part of this; it plans to maximize the potential of biotechnology for the benefit of EU economy, society and the environment. There are new challenges in this sector including a growing demand for healthy, safe food; an increasing risk of disease; and threats to agricultural and fishery production from changing weather patterns.

However, creating a bio economy is a challenging and complex process involving the convergence of different branches of science. Nanotechnology has the potential to revolutionize the agricultural and food industry with new tools for the molecular treatment of diseases, rapid disease detection, enhancing the ability of plants to absorb nutrients etc.

Smart sensors and smart delivery systems will help the agricultural industry combat viruses and other crop pathogens. In the near future nanostructured catalysts will be available which will increase the efficiency of pesticides and herbicides, allowing lower doses to be used. Nanotechnology will also protect the environment indirectly through the use of alternative (renewable) energy supplies, and filters or catalysts to reduce pollution and clean-up existing pollutants. An agricultural methodology widely used in the USA, Europe and Japan, which efficiently utilises modern technology for crop management, is called Controlled Environment Agriculture (CEA).
CEA is an advanced and intensive form of hydroponically-based agriculture. Plants are grown within a controlled environment so that horticultural practices can be optimized. The computerized system monitors and regulates localised environments such as fields of crops. CEA technology, as it exists today, provides an excellent platform for the introduction of nanotechnology to agriculture. With many of the monitoring and control systems already in place, nanotechnological devices for CEA that provide “scouting” capabilities could tremendously improve the grower’s ability to determine the best time of harvest for the crop, the vitality of the crop, and food security issues, such as microbial or chemical contamination.

Agriculture is the backbone of most developing countries, with more than 60% of the population reliant on it for their livelihood. As well as developing improved systems for monitoring environmental conditions and delivering nutrients or pesticides as appropriate, nanotechnology can improve our understanding of the biology of different crops and thus potentially enhance yields or nutritional values. In addition, it can offer routes to added value crops or environmental remediation. Particle farming is one such example, which yields nanoparticles for industrial use by growing plants in defined soils. For example, research has shown that alfalfa plants grown in gold rich soil absorb gold nanoparticles through their roots and accumulate these in their tissues. The gold nanoparticles can be mechanically separated from the plant tissue following harvest.
Nanotechnology can also be used to clean ground water. The US company Argonide is using 2 nm diameter aluminium oxide nanofibres (NanoCeram) as a water purifier. Filters made from these fibres can remove viruses, bacteria and protozoan cysts from water.  Similar projects are taking place elsewhere, particularly in developing countries such as India and South Africa. The German chemical group BASF’s future business fund has devoted a significant proportion of its 105 million USD nanotechnology research fund to water purification techniques.

The French utility company Generale des Eaux has also developed its own Nanofiltration technology in collaboration with the Dow Chemical subsidiary Filmtec. Ondeo, the water unit of French conglomerate Suez, has meanwhile installed what it calls an ultrafiltration system, with holes of 0.1 microns in size, in one of its plants outside Paris.  While some companies are working on water filtration, others such as Altairnano are following a purification approach. Altairnano’s Nanocheck contains lanthanum nanoparticles that absorb phosphates from aqueous environments. Applying these in ponds and swimming pools effectively removes available phosphates and as a result prevents the growth of algae.

The company expects this product to benefit commercial fish ponds which spend huge amounts of money to remove algae. Research at Lehigh University in the US shows that an ultrafine, nanoscale powder made from iron can be used as an effective tool for cleaning up contaminated soil and groundwater- a trillion-dollar problem that encompasses more than 1000 still-untreated Superfund sites (uncontrolled or abandoned places where hazardous waste is located) in the United States, some 150,000 underground storage tank releases, and a huge number of landfills, abandoned mines, and industrial sites.

The iron nanoparticles catalyse the oxidation and breakdown of organic contaminants such as trichloroethene, carbon tetrachloride, dioxins, and PCBs to simpler carbon compounds which are much less toxic. This could pave the way for a nano-aquaculture, which would be beneficial for a large number of farmers across the world.

Other research at the Centre for Biological and Environmental Nanotechnology (CBEN) has shown that nanoscale iron oxide particles are extremely effective at binding and removing arsenic from groundwater (something which affects the water supply of millions of people in the developing world, and for which there is no effective existing solution).

The impact of nanotechnology in the food industry has become more apparent over the last few years with the organization of various conferences dedicated to the topic, initiation of consortia for better and safe food, along with increased coverage in the media. Several companies which were hesitant about revealing their research programmes in nanofood, have now gone public announcing plans to improve existing products and develop new ones to maintain market dominance. The types of application include: smart packaging, on demand preservatives, and interactive foods.

Building on the concept of “on-demand” food, the idea of interactive food is to allow consumers to modify food depending on their own nutritional needs or tastes. The concept is that thousands of nanocapsules containing flavour or colour enhancers or added nutritional elements (such as vitamins), would remain dormant in the food and only be released when triggered by the consumer.  Most of the food giants including Nestle, Kraft, Heinz, and Unilever support specific research programmes to capture a share of the nanofood market in the next decade. The definition of nanofood is that nanotechnology techniques or tools are used during cultivation, production, processing, or packaging of the food. It does not mean atomically modified food or food produced by nanomachines.

Although there are ambitious thoughts of creating molecular food using nanomachines, this is unrealistic in the foreseeable future. Instead nanotechnologists are more optimistic about the potential to change the existing system of food processing and to ensure the safety of food products, creating a healthy food culture. They are also hopeful of enhancing the nutritional quality of food through selected additives and improvements to the way the body digests and absorbs food. Although some of these goals are further away, the food packaging industry already incorporates nanotechnology in products. Globally, many countries have identified the potential of nanotechnology in the agrifood sector and are investing a significant amount in it.
The United States Department of Agriculture (USDA) has set out ambitious plans to be achieved in the short, medium and long term, and aims to discover novel phenomena, processes and tools to address challenges faced by the agricultural sector. Equal importance has been given to the societal issues associated with nanotechnology and to improve public awareness. The UK’s Food Standards Agency (FSA) has commissioned studies to assess new and potential applications of nanotechnology in food, especially on packaging. At the same time more money has been given by other Government departments towards research and development which includes the development of functional food, nutrient delivery systems and methods for optimizing food appearance, such as colour, flavour and consistency.

This R&D is not just restricted to developed countries. Developing countries such as Iran have adopted their own nanotechnology programmes with a specific focus on agricultural applications. The Iranian Agricultural ministry is supporting a consortium of 35 laboratories working on a project to expand the use of nanotechnology in agro sector.  The ministry is also planning to hold training programs to develop specialized human resources in the field. They have already produced their first commercial nanotechnology product Nanocid, a powerful antibacterial product which has potential applications in the food industry. The product has also widespread applications in the production of various kinds of detergents, paints, ceramics, air conditioning systems, vacuum cleaners, home appliances, shoes and garments. India has allocated 22.6 million USD in its 2006 budget to the Punjab Agricultural University in Ludhiana, in acknowledgement of its pioneering contribution to the Green Revolution. Its research on high-yielding crop varieties helped boost food production in the 1960s and new projects include the development of new tools and techniques for the agriculture industry.

Whatever the impacts of nanotechnology on the food industry and products entering the market, the safety of food will remain the prime concern. This need will strengthen the adoption of nanotechnology in sensing applications, which will ensure food safety and security, as well as technology which alerts customers and shopkeepers when a food is nearing the end of its shelf-life. New antimicrobial coatings and dirt repellent plastic bags are a remarkable improvement in ensuring the safety and security of packaged food.

However, there is concern over the use of nanoparticles in food and its manipulation using nanotechnologies, which has the potential to elicit the same issues raised in the GM debate. In this context, a recent report from the Institute of Food Science and Technology in the UK, argues that more safety data is required before nanoparticles can be included in food. The report points out that current legislation does not force companies to label food items containing nanoparticles; and so consumers are unlikely to be aware of such applications in food items. It calls for an appropriate pre-market safety evaluation focusing on the effects of particle size as well as composition. 

The ETC group has gone further and has called for a moratorium on nanotechnology for agrifood.  It has also accused major companies and high tech universities of seeking patents on new food items which may shut out innovative companies in less developed countries.  Finally, it may be possible one day to manufacture food from component atoms and molecules, so-called “Molecular Food Manufacturing”.

Already some research groups are exploring this, but still from a top-down approach, using cells rather than molecules. Although the practical application of such technology is far into the future, it is expected that this could allow a more efficient and sustainable food production process to be developed where less raw materials are consumed and food of a higher nutritional quality is obtained.

Dr. Md. Sultan Mahmud is a Professor of Physics & Head at Department of Basic Sciences & Humanities, University of Asia Pacific Bangladesh.

BDST: 1749 HRS, APR 02, 2014