KDB Tech- Dhruba Jyoti Sarkar1 & Irani Mukherjee2

Dhruba Jyoti Sarkar¹ & Irani Mukherjee²

The term nanotechnology has been derived from the Greek word nano, meaning dwarf, applies the principles of engineering, electronics, physical and material science, and manufacturing at a molecular or submicron level. The origins of nanotechnology can be traced to Richard Feynman’s seminal paper in 1959 that “There’s plenty of room at the bottom”, in which he called for research into reducing the size of machines and data storage devices. Eric Drexler coined the term “nanotechnology” in 1986. Nanotechnology, new frontier in science and technology, is emerging as the technological platform for the second green revolution in Indian agriculture.  The essence of nanotechnology is the ability to work at the atomic and molecular levels to create novel structures or devices with the fundamentally new molecular organization.  Nanoparticles are commonly defined as particles with the size of at least one dimension ranging from 1 to 100 nm (Roco, 2003), which serve as a bridge between bulk materials and atoms/molecules (Nel et al., 2006). In recent past, nanoparticles have been applied in many areas because of their unique  physicochemical, electromagnetic, optical, and chemical catalytic properties (Gun'ko et al., 2009; Sreeja et al., 2009; Zhang et al., 2009; Khlebtsov et al., 2010) (Table 1). Nanomaterials display enhanced or unique properties due to their large surface to volume ratio and specific crystallographic surface structure compared to bulk materials which bring their applications in various industries (Table 2).

from the front or the back (Freestone et al., 2007). The cause of this effect was not, of course, known to those who exploited it. Nanoparticles have been used as colloids of gold, silver and copper to embellish calligraphy and in stained glass windows in medieval European churches (http://www.iinano.org/pre-18th-century). Carbon black is the most famous example of a nanoparticles material that has been produced in quantities for decades (http://www.nanodic.com/carbon/Carbon_Black.htm). In ancient Indian medical practices, therapeutic effects of gold and silver were known and put to use.              

 

Figure 2: The Lycurgus Cup from 4th century AD appears green when lit from the front, and red when lit from the back

Table 1 Properties and current applications of nanoparticles

Property	Applications
Optical	Anti-reflection coatings, tailored refractive index of surfaces, light based sensor for cancer diagnosis
Magnetic	Improved details and contrast property in MRI images, increased density storage media
Thermal	Enhance heat transfer from solar collectors to storage tanks, improved efficiency of coolants in transformers
Mechanical	Improved wear resistance, new anti-corrosion properties, new structural materials, composites, stronger and lighter
Electronic	High performance and smaller components, e,g, capacitors for small consumer devices such as mobile phones, displays which are cheaper, larger, brighter, and more efficient High conductivity materials

Table 2 Specific applications of nanomaterials

Area	Applications
Energy	High energy density and more durable batteries, hydrogen storage applications using metal nanoclusters, electro catalysts for high efficiency fuel cells, renewable energy, ultra high performance solar cells, catalysts for combustion engines to improve efficiency
Biomedical	Antibacterial silver coatings on wound dressings, sensors for disease detection (quantum dots), programmed release drug delivery systems
Environmental	Clean-up of soil contamination and pollution, biodegradable polymers, aids for germination, treatment of industrial emissions, more efficient and effective water filtration
Others	Activity of catalysts, coatings for self-cleaning surfaces, effective clear inorganic sunscreens

Nanotechnology in agriculture

The application of nanotechnology to the agricultural and food industries was first addressed by the United States Department of Agriculture in its roadmap published in September 2003 (USDA, 2003). It is now emerging as a rapidly evolving field with a potential to revolutionize agriculture and food systems (Kuzma and Verhage, 2006), across the entire agricultural value chain (Ward and Datta, 2005). In India too, nanotechnology is beginning to be seen as an important option for enhancing agricultural productivity, along with other emerging technologies such as biotechnology, to complement conventional agricultural technologies (Majumder et al., 2007; Kalpana Sastry et al., 2007). So far, the use of nanotechnology in agriculture has been mostly theoretical, but it has begun and will continue to have a significant effect in the main areas of the food industry: development of new functional materials, product development, and design of methods and instrumentation for food safety and bio-security. It has the potential to revolutionize the agricultural and food industry with new tools for the treatment of pests and diseases, rapid disease detection, smart delivery of pesticides and nutrients which will enhance the ability of plants to absorb necessary elements. Proponents argue that pesticidal applications using nanotechnology promise to efficient use of pesticide, due to their more precise and targeted nature. As such, nanotechnology is frequently portrayed as introducing environmental benefits. According to Kalpana Sastry et al., 2010 areas in agriculture where nanotechnology has potential are described in Table 3.

Table 3: Key agri-food thematic areas where nanotechnology has potential applications

No.	Agri-food thematic areas
1.	Natural resource management- efficient use of soil, water, energy inputs
2.	Plant/animal disease diagnostics
3.	Delivery mechanism in plant system
4.	Delivery mechanism in soil system
5.	Delivery mechanism in animal system
6.	Use of agricultural waste/biomass/byproducts
7.	Tracking the horticultural/food value chain
8.	Food processing
9.	Food packaging
10.	Bio-industrial processes
11.	Risk assessment/safety
12.	Developing new genetic types/breed/cultivar
13.	Livestock breeding and improvement
14.	Ethical, social, legal, environmental implications

Nanotechnology in Precision farming

Precision farming has been a long-desired goal to maximize output (i.e. crop yields) while minimizing input (i.e. fertilizers, pesticides, etc.) through monitoring environmental variables and applying target action. Precision farming makes use of computer, global satellite positioning systems and remote sensing device to measure highly localized environmental conditions thus determining whether crops are growing at maximum efficiency or precisely identifying the nature and location of problems. By using centralized data to determine soil conditions and plant development, seeding, fertilizer, chemical and water use can be fine-tuned to lower production costs and potentially increase production. Although not fully implemented yet, tiny sensors and monitoring systems enabled by nanotechnology will have a large impact in future precision farming methodologies.

One major role for nanotechnology enabled device will be increased use of autonomous sensors linked to GPS system for real-time monitoring. These nanosensors could be distributed throughout the field where they can monitor soil conditions and crop growth. Wireless sensors are already being used in certain parts of USA and Australia.

The union of biotechnology and nanotechnology in sensors will create equipment of increased sensitivity, allowing an earlier response to environmental changes. For example: (a) Nanosensors utilizing carbon nanotubes or nanocantilevers are small enough to trap and measure individual proteins or even small molecules, (b) Nanoparticles or nanosurfaces can be engineered to trigger an electrical or chemicals signal in the presence of a contaminant such as bacteria and (c) other nanosensors work by triggering and enzymatic reaction or by using nanoengineered branched molecules called dendrimers as probes to bind target chemicals and proteins. Ultimately, precision farming, with the help to smart sensors, will allow enhanced productivity in agriculture by providing accurate information, thus helping farmers to make better decisions.

Figure 2: Nanosensors for early fungal infection detection in field

Nanoparticles for pest management

Silica is biocompatible and has been developed and commercialized for a number of years for medical applications. It can also be engineered as hollow nanoparticles with different pore diameters and shell of different thickness. This has led a number of research groups to investigate its potential as a drug delivery vehicle for medical and veterinary treatments and more recently for pesticides, such as avermectin and validamycin, where it has been shown to afford protection against UV degradation and controlled release dependent on pore diameter and shell thickness. Fumigants and residual insecticides are commonly used to combat stored grain pests. In recent years, consumers’ awareness of health hazard from residual toxicity and growing problem of insect resistance to these conventional insecticides have led the researchers to look for alternative strategies for stored grains protection. Nanosilicas have also been reported having insecticidal activity through dessication of insect’s cuticles. For example, nanosilica can be effective against stored grain insects. Diatomaceous earth was used to design amorphous nano sized hydrophilic, hydrophobic silica in 15-30 nm size range. These silica nanoparticles are expected to reduce the volume of application and kinetics of development of resistance in stored grain insect pests. Use of nanosilica is not preferred as crop protection agent in field condition due to its adverse effects excreted upon inhalation.

Nanoemulsions have received a great deal of attention from the pharmaceutical sector as potential vehicles for transdermal delivery of hydrophobic drugs. Nanoemulsions of pesticidal active ingredient have often been suggested to increase the uptake of the active ingredients, but supporting data in the context of plant-protection product remains scarce. However, some studies support the hypothesis of enhanced uptake. Nanoformulations developed by Piola et al., 2013 increased the bioavailability of the herbicide while avoiding a number of the adjuvants present in the current glyphosate formulations, which have been associated with toxicity to nontarget organisms. The glyphosate nanoemulsions prepared with various proportions of fatty acid methyl esters, organosilicon, and alkyl glucosides-showed an efficacy similar to, or slightly higher than the commercial glyphosate formulation.

Table 4: Some example of nanopesticides

Nanomaterials	Pesticides	Polymer used
Capsule	Imidacloprid	Lignin-polyethylene glycol-ethyl cellulose
	Neem seed oil	Alginate-glutaraldehyde
Clay	Imidacloprid/Cyromazine	Alginate bentonite
Granules	Imidacloprid/Cyromazine	Lignin
Gel	Cypermethrin	Methyl methacrylate and methacrylic acid with and without 2-hydroxy ethyl methacrylate crosslinkage
Film	Endosulfan	Starch based polyethylene
Fiber	Pheromones	Polyamide
Micelle	Rotenone	N-octadecanol-1-glycidyl ether)-O-sulfate chitosan octadecanol glycidyl ether
Resin	Pheromone	Vinyl ethylene and vinyl acetate
Sphere	Carbaryl	Glyceryl ester of fatty acids
Suspension	Carbofuran	Poly(methyl methacrylate)- poly(ethylene glycol)

Conclusion

Nanotechnology is the latest platform to achieve a second green revolution in Indian agriculture. One of the biggest advances afforded by a deployment of nanotechnologies in the production and storage of food crops is the principle of “doing more with less”. Already a handful of food and nutrition products containing invisible, unlabeled and unregulated nano-scale additives are available commercially. Likewise, a number of pesticides formulated at the nanoscale are ready to be released in the market. Despite the numerous potential advantages of nanotechnology and the growing trends in publications and patents, many agricultural applications have not yet made it to the market. Agro-nanotech innovative products are experiencing difficulties in reaching the market, making agriculture still a marginal sector for nanotechnology. Several factors could explain the scarcity of commercial applications such as high production costs of nanotech products, which are required in high volumes in the agricultural sectors, unclear technical benefits, and legislative uncertainties, as well as public opinion.

References

1.      Roco, M. C. (2003) Broader societal issues of nanotechnology.  J. Nanopart. Res. 5 :( 3–4) 181–189.

2.      Nel, A., Xia, T. et al. (2006) Toxic potential of materials at the nano level. Science 311(5761): 622-627.

3.      Gun'ko, V. M., Blitz, J. P. et al. (2009) Structural and adsorption characteristics and catalytic activity of titania and titania-containing nanomaterials.  J.Colloid Interface Sci. 330(1): 125-137.

4.      Sreeja, R., Aneesh, P. M. et al. (2009) Size-dependent optical nonlinearity of Au nanocrystals. J. Electrochemical Soc. 156(10).

5.      Zhang, X., He, X. et al. (2009) Biosynthesis of size-controlled gold nanoparticles using fungus, Penicillium sp. J. Nanosci. Nanotechno. 9(10): 5738-5744.

6.      Khlebtsov, N. G. and Dykman L. A. (2010) Optical properties and biomedical applications of plasmonic nanoparticles. J. Quant. Spectrosc. Ra. 111(1): 1-35.

7.      Freestone, I., Meeks, N., Sax, M. and Higgitt, C. (2007) The Lycurgus Cup – A Roman Nanotechnology, Gold Bulletin: 40/4. http://master-mcn.u-strasbg.fr/wp-content/uploads/2015/09/lycurgus.pdf

8.      USDA, Nanoscale Science and Engineering for Agriculture and Food Systems, Dept. of Agriculture, United States, 2003.

9.      Kuzma, J. and Verhage, P. Nanotechnology in agriculture and food production: anticipated applications, Project on Emerging Nanotechnologies and The Consortium on Law, Values and Health and Life Sciences. Centre for Science, Technology and Public Policy (CSTPP). September 2006, http://www.nanotechproject.org/50.

10.  Ward, H. C. and Datta, Nanotechnology for Agriculture and Food Systems — A View, 2005, p. 14, http://www.nano.ait.ac.th.

11.  Majumder,  D. D., Ulrichs, C., Majumder, D., Mewis, I., Thakur, A. R., Brahmachary, R. L., Banerjee, R., Rahman, A., Debnath, N., Seth, D., Das, S., Roy, I., Ghosh, A., Sagar, P., Schulz, C., Linh, N. Q., Goswami, A. (2007) Current status and future trends of nanoscale technology and its impact on modern computing, biology, medicine and agricultural biotechnology, Proceedings of the International Conference on Computing: Theory and Application, 2007, pp. 563–573.

12.  Kalpana Sastry, R., Rao, N. H., Cahoon, R. and Tucker, T.  (2007) Can nanotechnology provide the innovations for a second green revolution in Indian agriculture? Paper presented in poster session: 2007 NSF Nanoscale Science and Engineering Grantee Conference at NSF, Washington from Dec 3 to 6, 2007, http://www. nseresearch.org/2007/overviews.htm#d.

13.  Kalpana, Sastry and Rashmi H B, and Rao N.H, (2010) Nanotechnology-Based Precision Farming Technologies: An Assessment based on R&D Indicators. Society for Technology Management - Newletter.

14.  Piola, L., Fuchs, J., Oneto, M.L., Basack, S., Kesten, E., Casabé, N. (2013) Comparative toxicity of two glyphosate-based formulations to Eisenia andrei under laboratory conditions. Chemosphere 91, 545–551.

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¹Division of Agricultural Chemicals, ICAR-Indian Agricultural Research Institute, New Delhi-12, India