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Emulsification: The emulsification process allows mixing two liquids which are normally immiscible using an interface agent (surfactant). This process permits the incorporation of a lipid into an aqueous media or vice versa by forming droplets (dispersed phase) which remain dispersed into a continuous phase. Nanoemulsions have been commonly prepared by high-energy methods, using mechanical devices able to produce intense disruptive forces, namely, high shear stirrers, high pressure homogenizers and ultrasound generators. Coacervation: The coacervation technique involves the phase separation of a single or a mixture of polyelectrolyte from a solution and the subsequent deposition of the newly formed coacervate phase around the active ingredient. Further, a hydrocolloid shell can be cross-linked using an appropriate chemical or enzymatic cross-linker such as glutaraldehyde or transglutaminase, mainly to increase the robustness of the coacervate. Inclusion complexation: Inclusion complexation generally refers to the encapsulation of a supramolecular association of a ligand (encapsulated ingredient) into a cavity bearing substrate (shell material) through hydrogen bonding, van der Waals force or an entropy-driven hydrophobic effect. Nanoprecipitation: The nanoprecipitation method is also called solvent displacement. It is based on the spontaneous emulsification of the organic internal phase containing the dissolved polymer, drug and organic solvent into the aqueous external phase. Supercritical antisolvent precipitation: Carbon dioxide (CO2) is an attractive solvent alternative for a variety of chemical and industrial processes, especially because it is plentiful and inexpensive, and has properties that are between those of many liquids and gases. At room temperature and above its vapor pressure, CO2 exists as a liquid with density comparable to organic solvents, but with excellent wetting properties and a very low viscosity. Above its critical temperature and pressure (31 °C and 73.8 bar), CO2 is in the supercritical state and has gas like viscosities and liquid-like densities. Small changes in temperature or pressure cause dramatic changes in the density, viscosity, and dielectric properties of supercritical CO2, making it an unusually tunable, versatile, and selective solvent (Clark, 2009).
The loading of nutrients on the nanoparticles is usually done by (a) absorption on nanoparticles, (b) attachment on nanoparticles mediated by ligands, (c) encapsulation in nanoparticulate polymeric shell, (d) entrapment of polymeric nanoparticles, and (e) synthesis of nanoparticles composed of the nutrient itself
Nano Technology for UG students of Agriculture
Prof. P. K. Mani
Bidhan Chandra Krishi Viswavidyalaya,
Mohanpur, West Bengal, India
Nanotechnology for Precision Farming
There’s Plenty of Room at the Bottom
Cal Tech, 1959
“People tell me about miniaturization, and how far it has
progressed today. They tell me about electric motors that are
the size of the nail on your small finger. And there is a device
on the market, they tell me, by which you can write the
Lord's Prayer on the head of a pin. But that's nothing; that's
the most primitive, halting step in the direction I intend to
discuss. It is a staggeringly small world that is below.
In the year 2000, when they look back at this age, they will
wonder why it was not until the year 1960 that anybody
began seriously to move in this direction.
Why cannot we write the entire 24 volumes of the
Encyclopedia Brittanica on the head of a pin?”
This goal requires patterning at the 10 nanometer scale.
Types of nanomaterials
• Nanomaterials can…
• occur naturally
• be produced by human
activity either as a product
of another activity
• on purpose (engineered)
• Our focus: engineered
nanomaterials as these are
designed and integrated into
products because of the specific
characteristics of the nanomaterial
s (Introduction to Nanomaterials and
According to Royal Society, "Nanotechnologies are the
design, characterization, production and application of
structures, devices and systems by controlling shape and
size at nanometer scale"
Fig 3. Top-down and bottom-up techniques for the
production of nanocapsules. (Nano encapsulation )
In general, the pdn of
nanoparticles can be
performed by both the
“top-down” and the
not an exception.
For the former
achieved by the
application of energy,
while for the latter;
the aggregation of
monomers, ions, or
even atoms is
chemically to form
Surface Areas at the Nanoscale
1 mm cubes1 cm cubes 1 nm cubes
Potential applications of nanotechnology in agriculture.
(A) Increase the productivity using nanopesticides and nanofertilizers;
(B) Improve the quality of the soil using nanozeolites and hydrogels;
(C) Stimulate plant growth using nanomaterials (SiO2, TiO2, and Carbon Nanotubes, CNT);
(D) Provide smart monitoring using nanosensors by wireless communication devices.
A schematic representation of
different aspects of
nanotechnology in agriculture is
shown in Fig. 4.
Detection of agrochemicals e.g. DDT,
Endosulfun and chloropyrofos from H20
Nanosensors to monitor soil heath and
Slow release of agrochemicals e.g.
acetamprid and hexaconazole
Plant disease management e.g. nanosillver,
nano alumino silicate and TiO2 NPs
Enhancement of self life of agro products by
nanocoating e.g. AgNPs
Growth regulators e.g. Silver nanoparticles
Zeolites for soil water retentions
Nutrient/water delivery systems via selective
Quality enhancement of agri-products e.g. zinc
6 types of
Core criteria to evaluate their potential for practical agricultural applications
SDS, ranging from treatments with agrochemicals to delivery of
nucleic acids for genetic transformation
Boopathi et al. (2011)
These “nano-fertilizers” have high surface area, sorption
capacity, and controlled-release kinetics to targeted sites
attributing them as smart delivery system.
Smart Delivery System
“Smart delivery system” means combination of specifically
targeted, highly controlled, remotely regulated, and
multifunctional characteristic to avoid biological barriers
for successful targeting (Nair et al. 2010)
Poor use efficiency of current fertilizers is a major issue. For instance, in China, the
world’s largest consumer of nitrogen fertilizer, up to 50% of the nitrogen applied is lost
by volatilization and another 5–10% by leaching. Loss of fertilizers has severe
environmental consequences such as eutrophication.
Nanotechnology is applied in the sector of plant nutrition with the aim of increasing the
use efficiency of current fertilizers, either by improving the delivery of poorly
bioavailable elements (e.g. phosphorus, zinc) and/or by limiting losses of mobile
nutrients to the surrounding environment ( nitrate).
Depending on the role of the nanomaterials, and the nutrients in use,
nanofertilizers can be separated into three different categories:
(1) Nanomaterials made of macronutrients,
(2) Nanomaterials made of micronutrients, and
(3) Nanomaterials acting as carriers for macronutrients.
Some researchers refer to the first two categories only as nanofertilizers, and the third
category(3) is ‘nutrient-loaded nanofertilizers’ or ‘nanomaterial-enhanced
Recent examples for category 1, 2 and 3 nanofertilizers are
layered double hydroxides intercalated with phosphate ions
nano chitosan-NPK fertilizers. and
ZnO nanoparticles, respectively.
Nanofertilizer refers to a product that delivers
nutrients to crops in one of three ways:
1. The nutrient can be encapsulated inside Nano-materials
such as nanotubes or nanoporous materials,
2. coated with a thin protective polymer film,
3. delivered as particles or emulsions of nanoscale
Slow, targeted, efficient release becomes possible.
In some cases, the nano particles itself can be used
Properties Examples of Nanofertilizers-Enabled Technologies Conventional Technology
Nanosized formulation of mineral micronutrients may
improve solubility and dispersion of insoluble
nutrients in soil; reduce soil absorption and fixation
and increase the bio-availability.
Less bioavailalbility to
plants due to large
particle size and less
Nanostructured formulation might increase fertilizer
efficiency and uptake ratio of the soil nutrients in
crop production; and save fertilizer resource.
Bulk composite is not
available for roots resource
and decrease efficiency
Both release rate and release pattern of nutrients for
water-soluble fertilizers might be precisely controlled
through encapsulation in envelope forms of semi-
permeable membranes coated by resin-polymer;
waxes and sulphur.
Excess release of
fertilizers may produce
toxicity and destroy
ecological balance of soil
Nano-structured formulation can extend effective
duration of nutrient supply of fertilizers into soil.
Used by the plants at the
time of delivery, the rest is
converted into insoluble
salts in the soil.
Loss rate of
Nanostructured formulation can reduce loss rate of
fertilizer nutrients into soil by leaching and/or leaking.
High loss rate by
leaching, runoff and drift.
Comparison of Nanotechnology based formulations and conventional fertilizer application
Method of application of Nano fertilizer
The formulation of any nano-fertilizer should be in such a way that
they possess all
desired properties such as
high solubility, stability, effectiveness, time-controlled release ,
enhanced targeted activity with effective concentration, and
less eco-toxicity with safe, easy mode of delivery and disposal.
Nanoparticles have great potential to deliver nutrients to specific
in slow release
the plant due
A schematic representation of delivery of pesticides /fungicides/nutrients
from nanocoating is shown in this figure
Novel Slow-Release Nanocomposite Nitrogen Fertilizers: The Impact of Polymers on
Nanocomposite Properties and Function
Conceptual release of ZNO2 NPS”
Under nutrient limitation, crops can secrete certain compounds into
rhizosphere to enable biotic mineralization of N or P from SOM and
P-associated with soil organic colloids.
exudates can be
signals that can
be recognised by
and release of
with the plant’s
Smart delivery of nano encapsulated herbicide in the crop-weed
environment. Nanoparticles targetting specific receptor of weed
Nano technology in Weed Management
Developing a target specific herbicide molecule encapsulated with
nanoparticle is aimed at specific receptor in the roots of target
weeds, which enter into root system and translocated to parts that inhibit
glycolysis of food reserve in the root system. This will make the specific
weed plant to starve for food and gets died.
Nano-pesticides: Solution or threat for a cleaner and greener agriculture?
It is self perpetuating biological entity that is able to survive in harsh environment on its own.
Nanotechnology can be used to harness the full potential of seed. Seed production is a
tedious process especially in wind pollinated crops. Detecting pollen load that will cause
contamination is a sure method to ensure genetic purity. Pollen flight is determined by air
temperature, humidity, wind velocity and pollen production of the crop. Use of bio
nanosensors specific to contaminating pollen can help alert the possible contamination and
thus reduces contamination.
The same method can also be used to prevent pollen from Genetically modified crop from
contaminating field crops. Novel genes are being incorporated into /seeds and sold in the
market. Tracking of sold seeds could be done with the help of nano barcodes (Pena et al.,
2001) that are encodable, machine-readable, durable and sub-micron sized taggants.
Disease spread through seeds and many times stored seeds are killed by pathogens. Nano-
coating of seeds using elemental forms of Zn, Mn, Pa, Pt, Au, Ag will not only protect seeds
but used in far less quantities than done today. Seeds can also be imbibed with nano
encapsulations with specific bacterial strain termed as Smart Seed.
Khodakovskaya et al. (2009) have reported the use of carbon nanotube for improving the
germination of tomato seeds through better permeation of moisture. Their data show that
carbon nanotubes (CNTs) serve as new pores for water permeation by penetration of seed
coat and act as a passage to channelize the water from the substrate into the seeds. These
processes facilitate germination which can be exploited in rainfed agricultural system.
Application of nanotechnology in seed science
Carbon nanotubes (CNTs) were found to penetrate tomato seeds and
affect their germination and growth rates. Analytical methods indicated
that the CNTs are able to penetrate the thick seed coat and support water
uptake inside seeds, a process which can affect seed germination and
growth of tomato seedlings
Carbon Nanotubes Are Super Fertilizer