Agriculture Reference
In-Depth Information
9.3.4 Chitosan Nanoparticles
The antimicrobial properties of chitosan are well known (Trotel-Aziz et al.
2006
).
One of the important profiles of these materials is their biodegradability and
biocompatibility that enhance the transport of active polar compounds across
epithelial surfaces in several biological applications (Zhukovskii
2008
). Another
important property is their mucoadhesivity, facilitating the transport of this active
compound across cellular membranes. In special, this quality implies great potential
for use in the agrochemical industry (Prashanth and Tharanathan
2007
). Chitosan
can be functionalized through diethylenetriamine and propionic aldehyde in order
to modify the primary amine groups on this polymer. The diazeniumdiolates
(chitosan/NO adducts) were prepared by suspending the chitosan derivatives in a
sodium methoxide-methanol solution under NO gas. Diethylenetriamine-modified
chitosan results in high NO loadings due to an increase of the nucleophilic sites
(Gao et al.
2008
). Therefore, the combination of NO and modified chitosan may
find several applications in plants.
A combination of alginate/chitosan nanoparticles has been prepared as a vehicle
to deliver
S
-nitrosoglutathione (GSNO) as the NO donor. Positive and negative
surface charges on alginate/chitosan nanoparticles were obtained by changing
alginate-chitosan ratios. Kinetics of NO release from encapsulated GSNO showed
that nanoparticles decrease the rates of NO release, at physiological temperature, in
comparison with free GSNO. An important observation in this system was that
cytotoxicity for fibroblast V79 cells was not observed. These results showed the
great potential of NO donor in plants (Seabra et al.
2012
; Marcato et al.
2013
).
A series of chitosans with different degrees of acetylation and molecular weights
were reacted with gaseous nitric oxide (NO) to yield [NONO]
groups. Hetero-
geneous reaction of NO with NH
2
groups present in chitosan was shown to be
dependent to the crystalline form of chitosan. Total NO release exhibited a bell-
shaped distribution at different degrees of acetylation (Wan et al.
2010
).
9.3.5 Polyester Nanoparticles
Fungicides and organic wood preservatives incorporated into wood products can
reduce wood decay. This can be achieved by the use of biocide-containing polyester
nanoparticles (Liu et al.
2002
,
2003
). In this way, nanoparticulate polyester formu-
lations have an important potential as novel agrochemicals with high specificity and
improved functions. The first tunable NO-releasing polymeric microparticles were
reported by Parzuchowski et al. (
2002
). Encapsulated NO prodrug diethylene-
triamine/NONOate into poly(lactic-co-glycolic) acid (PLGA) microparticles was
responsive to protect the prodrug from dissociation under acidic conditions and to
promote controlled release of NO (Yoo and Lee
2006
). PLGA encapsulated with a
ruthenium nitrosyl complex was found to be cytotoxic upon light irradiation.
