Agriculture Reference
In-Depth Information
9.3.7 Metalloids and Metallic Nanoparticles
Some metalloids, such as silicon, are semiconductors; hence, they can carry an
electrical charge under special conditions. This property makes metalloids useful in
computers and calculators. Metal nanoclusters exhibit unusual chemical and phys-
ical properties different from those of the bulk material or of the atoms and
exhibited potential applications in heterogeneous catalysis, micro- and
nanoelectronics, and optoelectronics devices. Due to the nanosize dimension, the
presence of a large percentage of surface atoms occurred, and when nanoclusters
are deposited on surfaces, their physical and chemical properties are strongly
dependent not only on their particle size and chemical composition but also on
the structure of the surface and that of the metal/substrate interface.
9.3.7.1 Silica Nanoparticles
Silica-based nanomaterials in the last years have been extensively studied due to the
desirable aspects of silica, such as chemical stability, versatility, and biocompati-
bility (Slowing et al.
2008
). Silica nanoparticles can be used as bioinsecticides in
agriculture (Barik et al.
2008
). These nanoparticles were successfully used as
vehicle to deliver DNA and active chemicals into plant cells, as well as to trigger
gene expression (Torney et al.
2007
). Porous hollow silica nanoparticles exerted a
shielding protection to pesticides from degradation by UV light, thus enhancing the
photostability of the pesticides (Li et al.
2007
).
Some reports showed evidence of possible use of silica as a NO-carrying and
delivering material, which may also be applied in agriculture. For example, Shin
et al. (
2007
) reported the advantages of NO-releasing silica nanoparticles over other
nanoparticle systems. This is due to the diversity of NO release kinetics, scaffold
nanoparticle size, and biocompatibility of silica. NO-release silica nanoparticles
were demonstrated to be highly effective against
Pseudomonas aeruginosa
and
nontoxic to human fibroblast cells. This fact showed the safe use of this
nanomaterial to kill bacterial infections (Hetrick et al.
2008
). Silica particles were
functionalized with
N
-diazeniumdiolate NO donors against Gram-negative
P. aeruginosa
and Gram-positive
Staphylococcus aureus
biofilms as a function of
particle size and shape. Smaller NO-releasing particles (14 nm) exhibited better NO
delivery and enhanced bacterial killing compared to the larger (50 and 150 nm)
particles (Slomberg et al.
2013
).
In this scenario, based on the capacity of silica nanoparticles to tune NO storage
and release, as well as their small particle size and biocompatibility, this material
could be important in new NO-based applications in plants (Seabra et al.
2013
).
