Nanotechnology and its applications in crop

improvement

Nanotechnology and its applications in crop improvement

Abstract

Nanotechnology is the Design, Fabrication and Utilization of materials, devices

and systems through control of matter on the nanometer length scale and exploitation of novel phenomena and properties (physical, chemical, biological) at that length scale. It is now more properly labeled as "molecular nanotechnology" (MNT) or "nano-scale engineering”. By taking advantage of quantum-level properties, nanotechnology allows for unprecedented control of the material world, at the nanoscale, providing the means by which systems and materials can be built with exact specifications and characteristics, allowing materials to be lighter, stronger, smarter, cheaper, cleaner and more precise. Nanotechnology has the potential to advance agricultural productivity through genetic improvement of plants, delivery of genes and drug molecules to specific sites at cellular levels, and nano-array based gene-technologies for gene expressions in plants and animals under stress conditions. The potential is increasing with suitable techniques and sensors being identified for precision agriculture, natural resource management, early detection of pathogens and contaminants in food products, smart delivery systems for agrochemicals like fertilizers and pesticides, smart systems integration for food processing, packaging and other areas like monitoring agricultural and food system security. Further developments in nanotechnology in this sector can be expected to become the main economic driving forces in the long run and benefit consumers, producers, farmers, ecosystems, and the general society at large.

In India, the importance of research and development in nanotechnology has been recognized as of paramount importance. If Indian agriculture is to attain its broad national goal of sustainable agricultural growth of over 4%, it is important that the nanotechnology research is extended to the agricultural total production-consumption system, that is, across the entire agricultural value chain.

Nanotechnology will give rise to a host of novel social, ethical, philosophical and legal issues. It is important to have a regulatory mechanism in place to predict and work to alleviate anticipated problems.

INTRODUCTION

Imagine a supercomputer a billion times more powerful than today’s and yet so small it would be barely visible by a light microscope. Fleets of medical robots smaller than a cell roaming our bodies eliminating bacteria, clearing out clogged arteries, reversing the ravages of old ages and effectively making us immortal. Clean factories manufacturing without having to worry about pollution choking up the environment. Cheap and abundant solar energy replacing conventional fossil fuels like oil, coal and gas. Building materials that are stronger, lighter and cheaper than the ones used in today’s

2

rockets, making lunar vacations no more expansive than says a trip to South Pole. A world where material abundance for all the people becomes a reality.

Sounds too good to be true? Not for the new breed of scientists who believe that the 21st century could see all these science fiction dreams come true thanks to nanotechnology, a hybrid of chemistry and engineering that has opened up a whole new world of possibilities which If taken to their logical conclusion would completely change us and the world as we know it today. Indeed, so exciting are the prospects of this revolutionary science that countries all over the world are investing in the research and development of nanotechnology. Clearly nanotechnology is slowly but surely capturing the attention of the scientific community, the media and no the public. But just what exactly is nanotechnology and why everyone talking about it?

WHAT IS NANOTECHNOLOGY?

Nanos: Greek term for dwarf, Technology: visualize, characterize, produce and manipulate matter of the size of 1 – 100 nm.

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 developments of such instruments and technique it is becoming possible to study and manipulate individual atoms.

At present, conventional manufacturing techniques manipulate billions of atoms at a time using large scale deformation methods like pounding and chipping. In the future, Molecular nanotechnology” will allow very complete control over the placement of individual atoms. Nanotechnology is often referred to as “bottom up” manufacturing because it aims to start with the smallest possible building materials, atoms using them to create a desired product. Working with individual atoms allow “atom –by –atom “design of structures. Nanotechnology can eliminate unwanted byproducts. Nanotechnology would allow us to get essentially every atom in the right place, make almost any structure consistent with the most of law of physics and chemistry that we can specify in atomic detail and have manufacturing costs not greatly exceeding the cost of the required raw materials and energy.

Related and interwoven fields include, but are not limited to: Nanomaterials, Nanomedicine, Nanobiotechnology, Nanolithography, Nanoelectronics, Nanomagnetics, Nanorobots, Biodevices [biomolecular machinery], AI, MEMS [MicroElectroMechanical Systems], NEMS [Nano Electro Mechanical Systems], Biomimetic Materials, Micro encapsulation, and many others.

DEFINITION

3

• “Nanotechnology is the Design, Fabrication and Utilization Of materials, Structures, devices and systems through control of matter on the nanometer length scale and exploitation of novel phenomena and properties (physical, chemical, biological) at that length scale In At Least One Dimension”.

• “A manufacturing technology able to inexpensively fabricate most structures consistent with natural laws and to do so with molecular precision”.

• “The precision, placement, measurement, manipulation and modeling of nanometer scale matter”.

• “The interactions of cellular and molecular components and engineered materials typically cluster of atoms, molecules and molecular fragments at the most elemental level of biology”.

• “By taking advantage of quantum-level properties, MNT allows for unprecedented control of the material world, at the nanoscale, providing the means by which systems and materials can be built with exact specifications and characteristics”.

Emergence of Nanotechnology

The first so-called scientific study of nanoparticles took place way back in 1831, when Michael Faraday investigated the ruby red colloids of gold and made public that the color was due to the small size of the metal particles. Gold and silver have found their way into glasses for over 2000 years, usually as nanoparticles. They have most frequently been employed as colorants, particularly for church windows. Until 1959, nobody had thought of using atoms and molecules for fabricating devices. It was first envisioned by Nobel Laureate Physicist Richard Feynman at a lecture entitled “There is plenty of room at the bottom”. It was much later in 1974 that Norio Taniguchi, a researcher at the University of Tokyo, Japan used the term “nanotechnology” while engineering the materials precisely at the nanometer level. The primary driving force for miniaturization at that time came from the electronics industry, which aimed to develop tools to create smaller electronic devices on silicon chips of 40–70 nm dimensions. The use of this term, “nanotechnology” has been growing to mean a whole range of tiny technologies, such as material sciences, where designing of new materials for wide-ranging applications are concerned; to electronics, where memories, computers, components and semiconductors are concerned; to biotechnology, where diagnostics and new drug delivery systems are concerned.

THE PIONEERS:

4

The word “Nanotechnology” coined in 1974 by Norio Taniguchi at the University of Tokyo. During the 1950s Arthur von Hippel, an electrical engineer from the Massachussetts Institute of Technology (MIT) coined the term “molecular engineering” and predicted the feasibility of constructing nanomolecular devices. However it was in December 29, 1959, the American physicist Richard Feynman gave a seminal lecture to the American Physical Society entitled “There’s Plenty of Room at the Bottom”. In this he discussed the benefits to society that would accrue if we were able to manipulate matter and manufacture artifacts with precision on a scale of a few atoms across, which corresponds to a dimension of about one nanometer. He correctly foresaw, for example, the impact that miniaturization would have on the capabilities of electronic computers; he also predicted the development of the methods that are now used to make integrated circuits and the emergence of techniques for writing extremely fine patterns with beams of electrons. He even mooted the possibilities of making machines at the molecular scale, which would enable us to manipulate chemical and

biological molecules. Forty years on from this lecture, technologists working in the field of nanotechnology are starting to realize some of the ideas originally propounded by Feynman, and many others that were not foreseen at that time.

Greg Binnig and Heinrich Rohrer in 1985 invented the scanning tunneling microscope. Eric Drexler, chairman of the Foresight Institute (1970s) in his book “Engine

5

of creation” has been written that future was one where everything would be built from the bottom up by tiny machines “nanomachines” or “assemblers” that would be able to build large scale objects that were perfect on the atomic scale.

Consequences of Miniaturization Every substance regardless of composition exhibits new properties when the size

is reduced to less than 100 nm. The electronic structure of a nanocrystal critically depends on its size. For small particles, the electronic energy levels are not continuous as in bulk materials, but discrete. This arises primarily due to confinement of electrons within particles of dimension smaller than the bulk electron delocalization length; this process is termed as quantum confinement. Noble metal and semiconductor nanoparticles are unique examples of this principle. Thus, the properties of traditional materials change at nano level due to the quantum effect and the behavior of surfaces start to dominate the behavior of bulk materials. The optical, electrical, mechanical, magnetic, and chemical properties can be systematically manipulated by adjusting the size, composition, and shape of the nanoscale materials. Nanomaterials have tremendous potential applications in catalysis, photocatalysis,optoelectronics, single-electron transistors, light emitters, nonlinear optical devices, hyperthermia treatment for malignant cells, magnetic memory storage devices, magnetic resonance imaging enhancement, cell labeling, cell tracking, in vivo imaging, and DNA detection. The wide range of applications shown by nanomaterials is mainly due to (i) large surface area and (ii) small size. Electron transport, manifested in phenomena like Coloumb blockade, as well as the catalytic and thermodynamic properties of structures can be tailored when one can rationally design materials on this length scale. Therefore, analytical tools and synthetic methods allow one to control composition and design on this nanometer range and will undoubtedly yield important advances in almost all fields of science.

NOBEL PRIZES FOR ELUCIDATING ATOMS AND SUBATOMIC PARTICLES.

S. No. WINNERS ACHIEVEMENTNOBEL PRIZE

1. Gerd Binnig, Heinrich Rohrer.

Scanning Tunneling Microscope. 1986

2. Hans Dehmelt, Wolfgang Paul.

Traps to isolate atoms and subatomic species. 1989

3. George Charpak Subatomic Particle detectors 1992

6

4. Clifford Schull, Bertram Brockhouse.

Neutron Diffraction technique for Structure determination

1994

5. Steven Chu, Claude Cohen -Tannoudji, William Phillips

Methods to cool and trap atoms with Laser light 1997

HOW BIG IS NANOTECHNOLOGY?

"Nanometer" (abbreviated nm), derived from the Greek word for midget, "NANO" is a metric prefix and indicates a billionth part (10-9). A micron is a millionth of a meter, which is the scale that is relevant to building computers, computer memory, and logic devices. A nanometer is one thousandth of a micron, and a thousandth of a millionth of a meter (a billionth of a meter). A nanometer is about the width of six bonded carbon atoms, and approximately 40,000 are needed to equal the width of an average human hair.

Sizes of nanoscale objects –Nature vs. fabrication

Object DiameterHydrogen atom 0.1nmBuckminsterfullerene (C60 ) 1.0 nmSix carbon atoms aligned 1.0 nmDNA (width) 2.0 nmNanotube 3-30 nmProteins 5-50 nmQuantum Dots (of CdSe) 8.0 nmDip pen nanolithography features 10-15 nmDendrimers 10 nmMicrotubules 25nmRibosome 25 nmVirus 75-100 nmNanoparticles range from 1-100 nmSemiconductor chip features 90 nm

WHY NANOTECHNOLOGY?

It would enable computer designers to break through the Moore’s law, Intel co-founder Dr. Gordon Moore predicted that technology that went into integrated circuits would roughly double in power every 12-18 months. That is why the latest Pentium V chip clocking 3.2 gigahertz is about 25,000 times faster and packs 25,000 as the first

7

ever microchip, the Intel 4004 of 1971. Physicists say it will takes at least 10 years at the most before we are able to dream up a bigger, better, microchip on that slab of silicon. And that is where nanotechnology comes in: the ability to fashion electronic circuits–entire computers –with atom length nanowires or nanotubes, made from carbon rather than silicon may allow computer hardware to progress beyond physical barriers of Moore’s law.

• Limitations of resources: Waste problem. • Necessity: Increasing population, density increases and demand for new

technology.

NANOTECHNOLOGY IS MULTIDISCIPLINARY

WHAT IS UNIQUE ABOUT NANOTECHNOLOGY?• Small size (High surface to volume ratio), therefore requires self assemblers.• Significantly higher hardness, breaking strength and toughness at low

temperatures and super plasticity at high temperatures, the emergence of additional electronic states, high chemical selectivity of surface sites and significantly increased surface energy.

8

• New entry ways (high mobility in human body, plants and environment).

Applications of Nanotechnology in Agriculture

Crop improvement

Nanobiotechnology

Analysis of gene expression and Regulation

Soil management

Plant disease diagnostics

Efficient pesticides and fertilizers

Water management

Bioprocessing

Post Harvest Technology

Monitoring the identity and quality of agricultural produce

Precision agriculture

Nanotechnology for Crop Improvement

DNA in Nano World

The DNA molecule has appealing features for use in nanotechnology: its

minuscule size, with a diameter of about 2 nanometers, its short structural repeat (helical

pitch) of about 3.4–3.6 nm, and its ‘stiffness’, with a persistence length (a measure of

stiffness) of round 50 nm. There are two basic types of nanotechnological construction:

‘top-down’ systems are where microscopic manipulations of small numbers of atoms or

molecules fashion elegant patterns, while in ‘bottom-up’ constructions, many molecules

self-assemble in parallel steps, as a function of their molecular recognition properties. As

a chemically based assembly system, DNA will be a key player in bottom-up

nanotechnology. The origins of this approach date to the early 1970s, when in vitro

genetic manipulation was first performed by tacking together molecules with ‘sticky

9

ends’. A sticky end is a short single-stranded overhang protruding from the end of a

double-stranded helical DNA molecule. Like flaps of Velcro, two molecules with

complementary sticky ends — that is, their sticky ends have complementary

arrangements of the nucleotide bases adenine, cytosine, guanine and thymine — will

cohere to form a molecular complex. Sticky-ended cohesion is arguably the best example

of programmable molecular recognition: there is significant diversity to possible sticky

ends (4N for N-base sticky ends), and the product formed at the site of this cohesion is the

classic DNA double helix. Likewise, the convenience of solid support-based DNA

synthesis3 makes it is easy to program diverse sequences of sticky ends. Thus, sticky

ends offer both predictable control of intermolecular associations and predictable

geometry at the point of cohesion. Perhaps one could get similar affinity properties from

antibodies and antigens, but, in contrast to DNA sticky ends, the relative three-

dimensional orientation of the antibody and the antigen would need to be determined for

every new pair. The nucleic acids seem to be unique in this regard, providing a tractable,

diverse and programmable system with remarkable control over intermolecular

interactions, coupled with known structures for their complexes.

Nanobiotechnology: Molecular biology complementing Nanotechnology

The credit for the term "nanobiotechnology" goes to Lynn W. Jelinski, a

biophysicist at Cornell University. Nanobiotechnology joins the breakthroughs in

nanotechnology to those in molecular biology. Molecular biologists help

nanotechnologists understand and access the nanostructures and nanomachines designed

by 4 billion years of natural engineering and evolution — cell machinery and biological

molecules. Exploiting the extraordinary properties of biological molecules and cell

processes, nanotechnologists can accomplish many goals that are difficult or impossible

to achieve by other means. For example, rather than build silicon scaffolding for

nanostructures, DNA's ladder structure provides nanotechnologists with a natural

framework for assembling nanostructures; and its highly specific bonding properties

bring atoms together in a predictable pattern to create a nanostructure. Nanotechnologists

also rely on the self-assembling properties of biological molecules to create

nanostructures, such as lipids that spontaneously form liquid crystals.

DNA has been used not only to build nanostructures but also as an essential

component of nanomachines. Most appropriately, DNA, the information storage

molecule, may serve as the basis of the next generation of computers. As microprocessors

and microcircuits shrink to nanoprocessors and nanocircuits, DNA molecules mounted

onto silicon chips may replace microchips with electron flow-channels etched in silicon.

Such biochips are DNA-based processors that use DNA's extraordinary information

10

storage capacity. Conceptually, they are very different from the DNA chips discussed

below. Biochips exploit the properties of DNA to solve computational problems; in

essence, they use DNA to do math. Scientists have shown that 1,000 DNA molecules can

solve in four months computational problems that require a century for a computer to

solve. Other biological molecules are assisting in our continual quest to store and transmit

more information in smaller places. For example, some researchers are using light-

absorbing molecules, such as those found in our retinas, to increase the storage capacity

of CDs a thousand-fold.

Nanobiotechnology is an emerging area of opportunity that seeks to fuse

nano/microfabrication and biosystems to the benefit of both. It relates to all applications

of genomics including mammalian, plant and microbial. It provides the basic tools and

subsequently the technology for gathering sequence information and designing

innovative devices to probe questions related to the biological importance of the genomic

information and the application of this knowledge in diverse fields, particularly medicine

and agriculture.

Potential Applications of Nanobiotechnology in Agriculture

• High throughput DNA sequencing and nanofabricated gel-free systems

• Microarrays and expression profiling

• Increasing the speed and power of disease diagnostics

• Creating bio-nanostructures for getting functional molecules into cells

• Miniaturizing biosensors

The impact of nanobiotechnology may be immediately felt in the following areas:

Nanofabricated Gel-free Systems and High Throughput DNA Sequencing

As a central process, DNA sequencing needs to be improved in terms of its

throughput and accuracy. Nanofabrication technology will be critical toward this goal

both in terms of improving existing methods as well as delivering novel approaches for

sequence detection. The scaling down in size of the current sequencing technology allows

the process to be more parallel and multiplex. Research in nanobiotechnology is

advancing toward the ability to sequence DNA in nanofabricated gel-free systems, which

would allow for significantly more rapid DNA sequencing. Coupled with powerful

approaches such as association genetic analysis, DNA sequencing data of the crop

germplasm, including the cultivated crop gene pool and the wild relatives can potentially

provide highly useful information about molecular markers associated with

agronomically and economically important traits. Thus, nanobiotechnology can enhance

the pace of progress in molecular marker-assisted breeding for crop improvement.

11

Microarrays and Expression Profiling

Microarray-based hybridization methods allow to simultaneously measure the

expression level for thousands of genes. Such measurements contain information about

many different aspects of gene regulation and function, and indeed this type of

experiments has become a central tool in biological research. The development of novel

formats for sequence determination and patterns of genomic expression which can have

significantly higher throughput than current technologies is vital. Thousands of DNA or

protein molecules are arrayed on glass slides to create DNA chips and protein chips,

respectively. Recent developments in microarray technology use customized beads in

place of glass slides. Overall, nanofabrication techniques can be used, for example, to

pattern surface chemistry for a variety of biosensor and biomedical applications.

Three areas which exemplify this are:

• Determination of new genomic sequences

• Scanning of genes for polymorphism that might have an impact on phenotype

• Comprehensive survey of the pattern of gene(s) expression in organisms when

exposed to biotic/abiotic stress.

The fundamental principle underlying the microarray technology has inspired researchers

to create many types of microarrays to answer scientific questions and discover new

products.

DNA Microarrays: DNA microarrays are being used to:

• detect mutations in disease-related genes

• monitor gene activity

• identify genes important to crop productivity

• improve screening for microbes used in bioremediation

Gene sequence and mapping data mean little until we determine what those genes do—

which is where protein arrays come in.

Protein Microarrays: While going from DNA arrays to protein arrays is a logical step, it

is by no means simple to accomplish. The structures and functions of proteins are much

more complicated than that of DNA, and proteins are less stable than DNA. Each cell

type contains thousands of different proteins, some of which are unique to that cell's job.

In addition, a cell's protein profile varies with its health, age, and current and past

environmental conditions.

12

Protein microarrays are being used to:

• discover protein biomarkers that indicate disease stages

• assess potential efficacy and toxicity of pesticides (natural and synthetics)

• measure differential protein production across cell types and developmental stages,

and in both healthy and diseased states

• study the relationship between protein structure and function evaluate binding

interactions between proteins and other molecules

Atomically Modified Seeds:

In March 2004, ETC Group reported on a nanotech research initiative in Thailand that aims to atomically modify the characteristics of local rice varieties. In a three-year project at Chiang Mai University’s nuclear physics laboratory, researchers “drilled” a hole through the membrane of a rice cell in order to insert a nitrogen atom that would stimulate the rearrangement of the rice’s DNA. So far, researchers have been able to alter the colour of a local rice variety from purple to green. In a telephone interview, Dr. Thirapat Vilaithong, director of Chiang Mai’s Fast Neutron Research Facility, told Biodiversity Action Thailand (BIOTHAI) that their next target is Thailand’s famous Jasmine rice. The goal of their research is to develop Jasmine varieties that can be grown all year long, with shorter stems and improved grain colour. One of the attractions of this nano-scale technique, according to Dr. Vilaithong, is that, it does not require the controversial technique of genetic modification. “At least we can avoid it.”

Low-energy ion beam bombardment at energy levels in the range of 60–125 keV and ion fluences (dose) of 1×1016–5×1017 ions/cm2 was chosen for mutation induction in Thai jasmine rice (Oryza sativa L. cv. KDML 105) at Chiang Mai University. One of the rice mutants designated BKOS6 was characterized. The rice mutant was obtained from KDML 105 rice embryos bombarded with N++N2+ ions at an energy level of 60 keV and ion fluence of 2×1016 ions/cm2. Phenotypic variations of BKOS6 were short in stature, red/purple color in leaf sheath, collar, auricles, ligule, and dark brown stripes on leaf blade, dark brown seed coat and pericarp. The mutant's reproductive stage was found in off-season cultivation (March–July). HAT-RAPD (High Annealing Temperature-Random Amplified Polymorphic DNA) was applied for analysis of genomic variation in the mutant. Of 10 primers, two primers detected two additional DNA bands at 450 bp and 400 bp. DNA sequencing revealed that the 450 bp and the 400 bp fragments were 60% and 61% identity to amino acid sequence of flavanoid 3′hydroxylase and cytochrome P450 of O. sativa japonica, respectively.

13

Figure: The rice mutants designated BKOS6 was derived by bombardment with N++N2+ ions from KDML 105 rice embryos.

Synthetic Tree

In trees, evaporation of water from leaf cells called spongy mesophyll pulls water up through hollow cells in the trunk

14

(spongy mesophyll is the tissue in the lower half of this picture, a cross-section through a leaf). The strong, cohesive properties of water, responsible for its powerful surface tension, allow the water to exist at large negative pressures. But even the smallest bubble would explosively expand into the water, disrupting its flow in a process known as cavitation. The interface between the plant’s water system and the air, formed by the spongy mesophyll, must allow water to pass, but not the gas molecules that would cause cavitation.

Figure: The synthetic hydrogel mimics the trnaspiartion pattern of a typical plant system.

Trees grow many times taller - more than 100 metres in the case of the tallest redwoods. Yet they supply their leaves with a constant flow of water. They achieve this feat by keeping the water high up in their trunks under pressures many atmospheres below that of a vacuum.

Wheeler and Stroock report a duplication of this trick: they have created a tiny ‘synthetic tree’ through whose trunk water flows at pressures of around -10 atmospheres. To create their tree, Wheeler and Stroock use a hydrogel, which mimics the mesophyll by holding water in molecular-scale pores, smaller than those of other porous solids. As their respective ‘root’ and ‘leaf’, the authors formed two networks of channels, 10 micrometres in diameter, in a sheet of poly(hydroxyethyl methacrylate), and connected them by a single channel, the ‘trunk’. With the ‘root’ exposed to a source of water and the ‘leaf’ to a stream of damp air, water flows through the system powered solely by ‘leaf’ evaporation. The pressures developed in the trunk are some 15 times more negative than in any previously reported pumping system.

The device is shown in Figure of the paper. It is just 5 cm long, and the flow is a little over 2 micrograms of water per second — but from such small acorns do mighty oaks grow. The synthetic tree can provide a test device for theories of tree physiology and, scaled-up, the technology could find uses in passive pumps or cooling devices — evaporation makes the ‘leaf’ a heat sink. Also, the large negative pressures developed might be used to drag water out of even quite dry soils, simultaneously filtering out impurities by passage through the ‘root’ hydrogel. This process, which the authors dub “reverse reverse osmosis”, could form the basis of solar-powered mining of pure water in arid or contaminated environments.

Silica beaks Plant Cell

Imagine a tiny bundle of parallel tubes with each tube containing liquid and having a cap that is removable at will. How useful might these objects be in

15

biotechnology? François Torney, Brian Trewyn and colleagues1 at Iowa State University describe the use of mesoporous silica nanoparticles (MSNs) to deliver foreign genetic material into plant cells in a process known as transformation. They further show that the nanoparticles can carry and release effectors - small molecules that induce the expression of genes - within the plant cells in a controlled fashion.

Figure. Delivering DNA and their effector molecules into intact plant cells using mesoporous silica nanoparticles. a) A typical plant cell, illustrating the thick cell wall (cw). b) After action of the gene gun, MSNs (small circles), carrying the small effector molecule (β-estradiol) within the gold-capped structure and externally coated with plasmid DNA, penetrate the cell wall and, in some cases, enter the cytoplasm.

Torney and co-workers explored both the surface attachment and encapsulation properties of MSNs, using plant cells as the test-bed. Plants have a thick cell wall that impedes delivery of materials from the exterior (Fig. a). In preliminary experiments, Torney and colleagues incubated protoplasts — plant cells whose cell walls are removed -with fluorescently labelled MSNs. It was found that modifying the MSN surface with triethylene glycol was necessary for MSNs to penetrate the cells. This surface

16

modification also allowed DNA plasmids (cloned DNA segments) to adsorb onto the MSN surface.

Figure. Designer nanotubes based on mesoporous silica can now penetrate the thick cell walls of plants and deliver DNA and their activators. This opens the way to precisely manipulate gene expression in plants at the single-cell level.

After entering the protoplasts, the plasmid DNA was released from the MSNs and the green fluorescent protein (GFP) marker encoded in the DNA was expressed in the cells and detected by microscopy. Delivery is efficient because the minimum amount of DNA required to detect marker expression was 1,000-fold lower than that required when using conventional methods to deliver DNA into protoplasts. It seems that using MSNs as a means to deliver DNA in this way should gain popularity for protoplast-based gene expression studies.

Although delivering material into protoplasts is important, it is not a particularly common approach in plant biotechnology because the cell walls must first be removed. A popular tool used to deliver materials into plants with intact cell walls is the ‘gene gun’. The carrier particles, usually coated with DNA, enter the cells through the walls by bombardment using high-pressure gases or, less commonly, explosive rounds.

Despite the destructive nature of this method, recovery is efficient enough to allow the DNA to be expressed in the plants. The advantage of using MSNs with the gene gun is that both the DNA and small effector molecules can be delivered at the same time. This work stimulates a number of questions. What might be the effect of including combinations of effector molecules within the MSNs, and/or combinations of plasmid DNA on their surfaces? Can MSNs be designed to uncap under more selective conditions (for example, using laser light or in response to chemical changes in the plant cells)? Can MSNs be designed so they can be recapped? Answering these questions is by no means

17

easy, but the promise shown by MSNs in general, and this work in particular, suggests many more breakthroughs will emerge in this area.

Hormone and Antibiotics Delivery in plants

Protein and nucleic acid drugs usually have poor stability in physiological conditions. It is therefore essential for these drugs to be protected en route to their target disease sites in the body.

Controlled release involves the combination of a biocompatible material or device with a drug to be delivered in a way that it can be delivered to and released at diseased sites in a designed manner. Drug-delivery systems may rescue potential drug candidates by increasing solubility and stability by the application of coating of polymerdrug conjugates, polymeric micelles, polymeric nanospheres and nanocapsules, and polyplexes.

Polymer-drug conjugates (520nm) represent the smallest nanoparticulate delivery vehicles. The polymers used for such purposes are usually highly water-soluble and include synthetic polymers (for example, poly(ethylene glycol) (PEG)) and natural polymers (such as dextran).

E.g. a cyclodextrin-based polymer developed at Insert Therapeutics increases the slow and sustained release of streptomycin, in plants against viruses.

Nanofuels

Levesque’s lab (University of Otawwa) is working on nanoconversion of agricultural materials into valuable products. The design and development of new nanocatalysts for the conversion of vegetable oils into biobased fuels and biodegradable solvents is already under scientific examination, and could be greatly enhanced with the help of nanotechnological abilities. This is based on the concept that the organic fuels at nano scale would be able to give greater energy with lesser energy loss during conversion.

Particle Farming

Nanoparticles may not be produced in a laboratory, but grown in fields of genetically engineered crops – what might be called “particle farming.”

18

Research from the University of Texas-El Paso confirms that plants can also soak up nanoparticles that could be industrially harvested. In one particle farming experiment, alfalfa plants were grown on an artificially gold-rich soil; gold nanoparticles in the roots and along the entire shoot of the plants that had physical properties like those produced using conventional chemistry techniques, which are expensive and harmful to the environment.

The metals are extracted simply by dissolving the organic material.

National Chemistry Laboratory in Pune, India have been carrying out similar work with geranium leaves immersed in a gold-rich solution.

Seeding Iron

Russian Academy of Sciences reports that they have been able to improve the germination of tomato seeds by spraying a solution of iron nanoparticles on to fields. They report that application of nano-disperse iron at the rate of 10-30 µg/ml on Tomato seeds var. Gribovskii leads to stimulator of growth and hastens the process of germination of seeds simultaneously stimulating the development of the root system. This was presented by A.M. Prochorov et al., “The influence of very minute doses of nano-disperse iron on seed germination,” presentation given at the Ninth Foresight Conference on Molecular Nanotechnology, 2001.

Using Nanosensors on Crops and Nanoparticles in Fertilisers

Tiny sensors offer the possibility of monitoring pathogens on crops and livestock as well as measuring crop productivity. In addition, nanoparticles could increase the efficiency of fertilisers. However, the Swiss insurance company SwissRe warned in a report in 2004 that they could also increase the ability of potentially toxic substances, such as fertilisers, to penetrate deep layers of the soil and travel over greater distances.

A nanotech research initiative in Thailand aims to atomically modify the characteristics of local rice varieties - including the country's famous jasmine rice- and to circumvent the controversy over Genetically Modified Organisms (GMOs). Nanobiotech takes agriculture from the battleground of GMOs to the brave new world of Atomically Modified Organisms (AMOs).

Nanocides: Pesticides via Encapsulation

Pesticides containing nano-scale active ingredients are already on the market, and many of the world’s leading agrochemical firms are conducting R&D on the development of new nano-scale formulations of pesticides (see below, Gene Giants: Encapsulation R&D). For example: BASF of Germany, the world’s fourth ranking agrochemical

19

corporation (and the world’s largest chemical company), recognizes nanotech’s potential usefulness in the formulation of pesticides. BASF is conducting basic research and has applied for a patent on a pesticide formulation, “Nanoparticles Comprising a Crop Protection Agent,” that involves an active ingredient whose ideal particle size is between 10 and 150 nm. The advantage of the nano-formulation is that the pesticide dissolves more easily in water (to simplify application to crops); it is more stable and the killing-capacity of the chemical (herbicide, insecticide or fungicide) is optimized. Bayer Crop Science of Germany, the world’s second largest pesticide firm, has applied for a patent on agrochemicals in the form of an emulsion in which the active ingredient is made up of nanoscale droplets in the range of 10-400 nm. (An emulsion is a material in which one liquid is dispersed in another liquid – both mayonnaise and milk are emulsions.)

The company refers to the invention as a “microemulsion concentrate” with advantages such as reduced application rate, “a more rapid and reliable activity” and “extended long-term activity.” Syngenta, headquartered in Switzerland, is the world’s largest agrochemical corporation and third largest seed company. Syngenta already sells pesticide products formulated as emulsions containing nano-scale droplets.

Like Bayer Crop Science, Syngenta refers to these products as microemulsion concentrates. For example, Syngenta’s Primo MAXX Plant Growth Regulator (designed to keep golf course turf grass from growing too fast) and its Banner MAXX fungicide (for treating golf course turf grass) are oil-based pesticides mixed with water and then heated to create an emulsion. Syngenta claims that both products’ extremely small particle size of about 100 nm (or 0.1 micron) prevents spray tank filters from clogging, and the chemicals mix so completely in water that they won’t settle out in the spray tank. Banner MAXX fungicide will not separate from water for up to one year, whereas fungicides that contain larger particle size ingredients typically require agitation every two hours to prevent misapplications and clogging in the tank. Syngenta claims that the particle size of this formulation is about 250 times smaller than typical pesticide particles. According to Syngenta, it is absorbed into the plant’s system and cannot be washed off by rain or irrigation

Soil Binder - Using Chemical Reactions at the Nanoscale to Bind Soil Together

In 2003, ETC Group reported on a nanotech-based soil binder called SoilSet

developed by Sequoia Pacific Research of Utah (USA). SoilSet is a quick-setting mulch

which relies on chemical reactions on the nanoscale to bind the soil together. It was

sprayed over 1,400 acres of Encebado mountain in New Mexico to prevent erosion

following forest fires, as well as on smaller areas of forest burns in Mendecino County,

California.

20

Soil Clean-Up Using Iron Nanoparticles

A number of approaches are being developed to apply nanotechnology and

particularly nanoparticles to cleaning up soils contaminated with heavy metals and PCBs.

Dr. Wei-Xang Zhang has pioneered a nano clean-up method of injecting nano-scale iron

into a contaminated site. The particles flow along with the groundwater and

decontaminate en route, which is much less expensive than digging out the soil to treat it.

Dr. Zhang’s tests with nano-scale iron show significantly lower contaminant levels within

a day or two. The tests also show that the nano-scale iron will remain active in the soil for

six to eight weeks, after which time it dissolves in the groundwater and becomes

indistinguishable from naturally occurring iron.

Consumer products:

• Nanoscale powders, in their free form, without consolidation or blending, used by cosmetics manufacturers:

– Titanium Dioxide and Zinc Oxide powders for facial base creams and sunscreen lotions.

– Iron Oxide powders as base material for rouge and lipstick.• Improved wear and corrosion resistance. Nanocomposite materials, with increased

impact strength, for automobiles.

Disease diagnosis:

• Sample Retrieval: Develop retrieval nanosystems for sampling specific components (from air, plant and animal organisms, water, and soil).

• Pathogen Detection: Develop methods of near real time pathogen detection and location reporting using a systems approach, integrating nanotechnology micro-electromechanical systems (MEMS), wireless communication, chip design, and molecular biology for applications in agricultural security (economic, agricultural terrorism, agricultural forensics) and food safety

Quality maintain

Identity Preservation (IP) is a system that creates increased value by providing customers with information about the practices and activities used to produce a particular crop or other agricultural product. Certifying inspectors can take advantage of IP as a

21

more efficient way of recording, verifying, and certifying agricultural practices. Today, through IP it is possible to provide stakeholders and consumers with access to information, records and supplier protocols regarding such information as farm of origin, environmental practices used in production, food safety and quality and information regarding animal welfare issues. Some food or processed agricultural products may be stored for years, with intermittent samplings for storage pathogens or environmental storage problems. Each day shipments of food and other agricultural products are moved all over the world. Currently, there are financial limitations in the numbers of inspectors that can be employed at critical control points for the safe production, shipment and storage of food and other agricultural products. Quality assurance of agricultural products’ safety and security could be significantly improved through IP at the nanoscale. Nanoscale IP holds the possibility of the continuous tracking and recording of the history which a particular agricultural product experiences. We envision nanoscale monitors linked to recording and tracking devices to improve identity preservation of food and agricultural products.

Smart Treatment Delivery Systems

Today, application of agricultural fertilizers, pesticides, antibiotics, probiotics and nutrients is typically by spray or drench application to soil or plants, or through feed or injection systems to animals. Delivery of pesticides or medicines is either provided as “preventative” treatment, or is provided once the disease organism has multiplied and symptoms are evident in the plant or animal. Nanoscale devices are envisioned that would have the capability to detect and treat an infection, nutrient deficiency, or other health problem, long before symptoms were evident at the macro-scale. This type of treatment could be targeted to the area affected.

“Smart Delivery Systems” for agriculture can possess any combination of the following characteristics: time-controlled, spatially targeted, self regulated, remotely regulated, preprogrammed, or multifunctional characteristics to avoid biological barriers to successful targeting. Smart delivery systems also can have the capacity to monitor the effects of the delivery of pharmaceuticals, nutraceuticals, nutrients, food supplements, bioactive compounds, probiotics, chemicals, insecticides, fungicides, vaccinations, or water to people, animals, plants, insects, soils and the environment.

Nanotechnology and Indian Initiatives

22

At present, USA leads with a 4 year, 3.7 billion USD investment through its Nanotechnology Development Programme (NDP).

The market for the nanotechnology was 7.6 billion USD in 2003 and is expected to be 1 trillion USD in 2011

However, the full potential of nanotechnology in the agricultural and food industry has still not been realised.

23

24

Present area of activities in the field of Nanotechnology in India

The priority areas identified in Agriculture are:

• Detecting contamination in raw agriculture products

• Development of nano tubes devices to diagnoses diseases in agriculture crops.

• To detect carcinogenic pathogens and bio sensors for improved and contamination free agriculture products.

• Use of nano particles with bio compatible Chitosan

National Challenge Program on Nanobiotechnology and Food and Health Security

National Physical Laboratory, New Delhi has been entrusted as the nodal organization

• To meet the Millennium Development Goal of UN

25

• To prioritize the area of research and to measure the research outlay and scientific and social outcome

• To coordinate the research between ICAR, CSIR, ICMR, DST and DBT organizations.

DST has invested approx. $20million for the period 2004-2009.

OBSTACLES:

Unlike building with traditional materials that stay where you put them, atoms and molecules are volatile and will rearrange themselves constantly to maintain stability. So positional Control: must be achieved, and self-replication is necessary to reduce costs. It will also allow atoms to be placed precisely without parts bumping into each other in the wrong way. Eric Drexler has proposed a robotic arm to control the placement of atoms. The Stewart platform, which is stiffer and simpler than Drexler’s robotic arm, has also been proposed.

Nanotechnology : A Friend or Monster in The Making ?

Current status

Nanobiotechnology is still at its early stages of development the development is multi-directional and fast-paced. Universities are forming nanotechnology centers and the number of papers and patent applications in the area is rising quickly.

Realistically, some of these newly developed tools might not have viable applications and could end-up on the ‘technology shelf’ in the future but offcorse there are definite benefits.

Nanobiotechnology is interdisciplinary and brings together life scientists and engineers. This, in turn, fuels further growth of ideas, which would not occur without these interdisciplinary interactions.

Future trends

Developments will gradually become more ordered and develop sharp focus as applications mature to produce useful and validated technologies.

The question that whether the coming age of Nanotechnology is the Next technological revolution everyone talking about is still to be answered?

There is great optimism among scientists, politicians and policy makers who anticipate significant job creation.

26

Opportunities for developing new materials and methods that will enhance our ability to develop faster, more reliable and more sensitive analytical systems.

Overall the scenario presents us with the view that nanotechnology is here to stay!

Political, social or ethical concerns related to nanotechnology development

• Is Nanotechnology more acceptable compared to genetically modified products?

• The potential risks in using nanoparticles in agriculture are no different than those in any other industry.

• Proprietary issues associated with the nano-products.

• Since there is no standardization for the use and testing of nanotechnology, products incorporating the nanomaterials are being produced without check.

Conclusions

Some of the important conclusions that can be drawn are

• Nanotechnology is the engineering of tiny machines i.e. the ability to build things from the “bottom up”, manufacturing because it aims to start with the smallest possible building materials, ATOMS using them to create a desired product.

• By taking advantage of quantum-level properties, MNT allows for unprecedented control of the material world, at the nanoscale, providing the means by which systems and materials can be built with exact specifications and characteristics.

• Nanotechnology has wider uses in biotechnology, genetics, plant breeding, disease control, fertilizer technology, precision agriculture, and allied fields, etc.

SUMMARY:

NANOTECHNOLOGY IN A NUTSHELLNEW TECHNOLOGY : ATOMIC ENGINEERING : NEW MATERIALS : NEW PROPERTIES SIGNIFICANTS BENEFITS : CLEAN ENERGY : IMPROVED EFFICIENCY : BETTER WASTE TTREATMENTPOTENTIAL RISKS : HIGH MOBILITY ? : NOVEL TOXICITY ? : CORPORATE LIABILITY ?

27

So careful developments to achieve benefits and manage risks requires:

• CLEAR REGULATIONS

• RISK IDENTIFICATION RESEARCH

• RISK MANAGEMENT STANDARDS

• "Nanotechnology will give rise to a host of novel social, ethical, philosophical and legal issues. It will be important to have a group in place to predict and work to alleviate anticipated problems”.

• Both the government and the private sector have to join hands and form a “Nano tech Enterprise". If we take up a mission mode with a clear cut vision, the country will reap the benefits of Nanoscience and technology.

“Our future lies in Nanotechnology”

We believe that nanotechnology would give us an opportunity, if we take appropriate and timely action to become one of the important technological nations in the world. The world market in 2005 is for nano materials, nano tools, nano devices and nano biotechnology, which put together, is expected to be over hundred billion dollars. Nanotechnology is a new technology that is knocking at doors. (Source: president address to scientist and technologists in April 2005 in Delhi.)

28

Reference:-

A. Malato, J. Blanco, A. Vidal and C. Richter, “Photocatalysis with solar energy at a pilot-plant scale: an overview”, (2002), Applied Catalysis B: Environmental, Vol. 37, 1–15.

A. Mills, L. Punte, and M. Stephan, “An overview of semiconductor photocatalysis”, (1997), J. Photochem. Photobiol. A., Vol. 108, 1-35.

A. Sugunan, H. C. Warad, C. Thanachayanont, J. Dutta And H. Hofmann, “Zinc oxide nanowires on non-epitaxial substrates from colloidal processing for gas sensing applications”, Nanostructured and Advanced Materials for Applications in Sensor, Optoelectronic and Photovoltaic Technology, NATO-Advance Study Institute, Sozopol, Bulgaria, 6-17th September 2004

A.M. Prochorov et al., “The influence of very minute doses of nano-disperse iron on seed germination,” presentation given at the Ninth Foresight Conference on Molecular Nanotechnology, 2001.

Annonymous, 2004. Down on the farm: The impact of nano-scale technologies on food and agriculture. Action Group on Erosion Technology Concentration, Ottawa, Canada. www.etcgroup.org

B. Phanchaisri, R. Chandet, L.D. Yu, T. Vilaithong, S. Jamjod, S. Anuntalabhochai. Low-energy ion beam-induced mutation in Thai jasmine rice (Oryza sativa L. cv. KDML 105) Surface & Coatings Technology 201 (2007) 8024–8028.

C.F., Chau, Wu, Shiauan-Huei and Gow-Chin Yen. 2007. The development of regulations for food nanotechnology. Trends in Food Science and Technology. 18:269-280.

C.I. Moraru, 2003. Nanotechnology: A new frontier in food science. Food Technology 57(12):24-29.

D. Li, H. Haneda, “Morphologies of zinc oxide particles and their effects on photocatalysis’, (2003), Chemosphere, Vol. 51(2), 129-37

29

D. Maysinger, 2007. Nanoparticles and cells: Good companions and doomed partnerships. Org. Biomol. Chem. 5:2335-2342.

D. S. Bhatkhande, V. G. Pangarkar and A. A. C. M. Beenackers, “Photocatalytic degradation for environmental applications – A Review”, (2001), J. Chem. Technol. Biotechnol, Vol. 77, 102-116

E. C. Alocilja and S. M. Radke, ‘Market analysis of biosensors for food safety’, Biosensors and bielectronics, (2003), Vol. 18, 841-846.

ETC Group News Release, “Atomically Modified Rice in Asia?” 25 March 2004. Available on the Internet: www.etcgroup.org/article.asp?newsid=444

F. Kulzer and M. Orrit, “Single-Molecule Optics”, (2004), Annual Review of Physical Chemistry, Vol. 55, 585-611

F.R.R. Teles, L.P. Fonseca, Talanta (2008) Trends in DNA biosensors, Article in press doi:10.1016/j. Talanta.2008.07.024

F.X., Redl, Cho, K.S., Murray, C. B. and O’Brien, S. (2003). Three dimensional binary super lattices of magnetic nanocrystal &semiconductor quantum dots. Nature 424(6943), 968-971.

H. C. Warad, S. C. Ghosh, C. Thanachayanont and J. Dutta, ‘Highly Luminescent Manganese Doped ZnS Quantum Dots for Biological Labeling’, conference proceedings ‘Smart/Intelligent Materials and Nanotechnology’, Chiang Mai, Thailand, 1-3 December 2004.

http://www.nano.gov/

J. Dutta and H. Hofmann, “Self-Organization of Colloidal Nanoparticles”, (2004) Encyclopedia of Nanoscience and Nanotechnology, Vol. 9, 6 17-640.

J. M. Herrmann, “Heterogeneous photocatalysis: fundamentals and applications to the removal of various types of aqueous pollutants, (1999), Catalysis Today Vol. 53, 115–129.

30

J. Peral, X. Domenech and D. F. Ollis, “Heterogeneous photocatalysis for purification, decontamination and deodorization of air”, (1997), J. Chem. Technol. Biotechnol, Vol. 70, 117-140.

K. Yuen, U. Muller, and J. Lahiri, "Rare earth-doped glass microbarcodes",(2003), PNAS, Vol. 100, 389-393

Kroto, H. W., Heath, J. R., O’Brian, S. C., Curl, R. F. and Smalley, R. E., Nature, 1985, 318, 162–163.

L. C. Torres-Martínez, L. Nguyen, R. Kho, W. Bae, K. Bozhilov, V. Klimov and R. K Mehra, “Biomolecularly capped uniformly sized nanocrystalline materials: glutathione-capped ZnS nanocrystals”, (1999), Nanotechnology Vol. 10, 340-354

L. Vayssieres, K. Keis, S. E. Lindquist and A. Hagfeldt, “Purpose-Built Anisotropic Metal Oxide material: 3D Highly Oriented Microrod Array of ZnO” (2001), J Phys. chem. 105, 3350-3352

M. A., Poggi, Bottomley, L. A. and Lillehi, P.T. (2002). Scanning probe microscopy. Anal. chem. 74, 2851-2862.

M. Blake, “Bibliography of Work on Photocatalytic Removal of Hazardous Compounds from Water and Air”, (1997), NREL/TP-430-22197, National Renewable Energy Laboratory, Golden.

M. C., Roco, Williams, R. S., Alivasatos, P., Eds. Nanotechnology Research Directions: IWGN Workshop Report, Kluwer Academic Publishers: Norwell, MA, 1999.

M. H. Huang, Y. Wu, H. Feick, N. Tran, E. Weber and P. Yang, "Catalytic Growth of Zinc Oxide Nanowires by Vapor Transport" (2001), Adv. Mater., Vol. 13, 113-1 16.

M. J. Dejneka, A. Streltsov, S. Pal, A. G. Frutos, C. L. Powell, K. Yost, P. Nanomaterials by J. Dutta and H. Hofmann, Text book in preparation.

M. K. Hossain, S. C. Ghosh, Y. Boontongkong C. Thanachayanont and J. Dutta, “Growth of zinc oxide nanowires and nanobelts for gas sensing applications”, (2005), Journal of Metastable and Nanocrystalline Materials, Vol. 23, 27-30

31

M. Reches, and E. Gazit. (2003). Casting metal nano-wires within discrete self-assembled peptide noontides. Science. 300, 625-627.

P. D. Patel, “(Bio) sensors for measurement of analytes implicated in food safety: a review” (2002) Trends in analytical chemistry, Vol. 21, 96-115

P. Liu, Y.W. Zhang and C. Lu, “Finite element simulations of the self- organized growth of quantum dot superlattices”, (2003), Phys. Rev. 68, 195314.

P.A. Troshin, R.N. Lyubovskaya, I.N. Ioffe, N.B. Shustova, E. Kemnitz, S.I. Troyanov, Angew. Chem. Int. Ed. Engl. 44, 234 (2005).

P.M. Ajayan, Nanotechnology how does a nanofibre grow? (2004). Nature. 427, 402-403.

R. F., Curl, Angew. Chem., Int. Ed. Engl., 1997, 36, 1566– 1576; Kroto, R., Angew. Chem., Int. Ed. Engl., 1997, 36, 1578–1593;

R. Vacassy, S. M. Scholz, , J. Dutta, C. J. G. Plummer, R. Houriet and H. Hofmann , “Synthesis of controlled spherical Zinc Sulfide Particles by Precipitation from Homogeneous Solutions”, (1998), Journal of American Ceramic Society Vol. 81, 2699-2705

S. R. Nicewarner-Pena, R. G. Freeman, B. D. Reiss, L. He, D. J. Pena, I. D. Walton, R. Cromer, C. D. Keating and M. J. Natan, “Submicrometer metallic barcodes” (2001), Science, Vol. 294 (5540), 137-41

T.D. Wheeler, & Stroock, A.D. 2008. The transpiration of water at negative pressures in a synthetic tree. Nature. 455:208-212.

W., Ranjana. “Thailand embarks on the nano path to better rice and silk,” Bangkok Post, Jan. 21, 2004. Available on the Internet: http://www.smalltimes.com/document_display.cfm?document_id=7266

X. L. Su, Y. Li, “Quantum dot biolabeling coupled with immunomagnetic separation for detection of Escherichia coli O157:H7” (2004), Anal Chem. Vol. 76 (16), 4806-10.

32

Y. A. Cao, X. T. Zhang, W. S. Yang, H. Du, Y. B. Bai, T. J. Li, J. N. Yao, “Bicomponent TiO2/SnO2 particulate film for photocatalysis”, (2002), Chem. Mater., Vol. 12, 3445.

Y., Xia, Yang, P., Sun, Y., Wu, Y., Mayers, B., Gates, B., Yin, Y., Kim, F., and Yan, H. (2003).One dimensional nanostructures: synthesis, characterization and application. Adv. Mater.15 (5), 353-389.

33