Agriculture Reference
In-Depth Information
and Yada
2011
; Mousavi and Rezaei
2011
). Nanotechnology is generally related to
materials, systems, and processes that operate in a size scale of 0.1-100 nm. This
technology permits to take a look at the atomic and molecular level and to create
structures in the nanometer range. Using nanotechnology, it is possible to regulate
the catalysis of chemical reactions and to manipulate these nanoscale structures,
allowing the preparation of nanoparticles with many specific applications
(Sanguansri and Augustin
2006
).
The term nanoparticle has been applied to a variety of structures within the
nanometric scale and may also include the model of nanocapsules. Many
nanoparticles have a solid core or matrix, mostly composed of metallic atoms.
Because of their small size, nanoparticles show significant changes in their physical
properties as compared with larger particles of bulk materials. This significant size
reduction implies the emergence of quantum effects that lead to potentially useful
phenomena such as Coulomb blockade, superparamagnetism, and surface plasmon
resonance, among others. In addition, the increase in the surface area to volume
ratio causes the appearance of surface effects related to the high number of surface
atoms, as well as to a high specific area (Sharma et al.
2009
). Many different
materials are used for the manufacture of nanoparticles, including metal oxides,
magnetic materials, ceramics, silicates, carbon nanotubes (CNTs), and synthetic
and natural polymers (Faraji and Wipf
2009
). The synthesis of nanoparticles with
specific composition, size and of distinct properties has expanded the opportunity of
their applications in numerous industries including agriculture and food.
Conventional techniques of nanoparticle synthesis that usually employ atomic,
molecular, and particulate processing in vacuum or in a liquid medium are eco-
nomically expensive and inefficient in terms of materials and energy use. The
development of harmless and eco-friendly procedures for the synthesis of
nanomaterials based on green chemistry and biological processes constitutes a
growing demand. Therefore, several researchers have investigated biological pro-
cesses that present excellent control on particle size using microorganisms
(Korbekandi et al.
2009
). In particular, the utilization of fungi for preparation of
metallic nanoparticles has gained importance since they have some advantages as
compared with other organisms. A better manipulation and control over crystal
growth can be achieved due to slower fungi kinetics, fungal mycelia can resist flow
pressure and agitation in bioreactors, and many enzymes secreted by fungi are
capable of reducing metal ions, allowing a controlled synthesis of nanoparticles
with well-defined size and shape (Kashyap et al.
2013
).
Nanoparticles can serve as delivery systems to drugs, chemicals, or genes, which
target particular parts of the organism to release their contents. Due to their small
size, nanoparticles can enable effective penetration through cuticles and tissues,
allowing slow and constant release of the active substances (Suri et al.
2007
; Zhang
et al.
2010a
). Thus, nanotechnology creates new tools and materials for use in
biological systems, which can be useful to both diagnosis and therapeutic purposes
(Farokhzad and Langer
2006
; Kuzma
2010
). This convergence between nanotech-
nology and biology is called nanobiotechnology.
