Biomedical Engineering Reference
In-Depth Information
10.3.3.1 Nanoformulated Pesticides
The advent of nanopesticides (or nanoformulated pesticides) created debate
recently, including the regulatory issues that are applied to these chemicals
[9]. Industries in the agricultural sector will probably exploit the alleged
advantages of the NP-based pesticides; that is, the novel nanopesticide deliv-
ery systems, including nanocapsules, nanocontainers, and nanocages, could
replace conventional emulsifiable concentrates, thus reducing organic solvent
content in agricultural formulations, and enhancing dispersibility, wettabil-
ity, and the penetration strength of the droplets [9]. It is also expected that
enhanced use of smart systems could diminish runoff and avert unwanted
movement of pesticides [133]. Smart field systems detect, locate, and report/
apply, as needed, pesticide and fertilizers before the onset of symptoms [133].
Available chemical or toxicity information on commercial nanopesticides is
limited, probably due to proprietary reasons. A study by Cao et al. [7] indi-
cated that a chlorfenapyr nanoformulation has a slightly higher degradation
rate compared with the standard suspension (half-lives of 4.3 and 3.9 days,
respectively); their effects on nontarget organisms were not studied. Liu et
al. [8] reported that nanosized pesticide particles could produce better spa-
tial distribution of the agent on the surface of leaves, as well as increase the
absorption of the pesticide by leaf-chewing organisms. Another proposed
advantage is a reduced risk of exposure for workers by elimination of hand-
ling of pesticide solutions in oil, which have a high potential to be absorbed
transdermally. Ecotoxicological effects have not been reported.
TABLE 10.4
Summary of (Eco)toxicity Studies of Polymers and Dendrimers
Nanomaterial
(Size)
Test Organism
Effect
References
NIPAM/BAM
(50-70 nm)
Microtox, alga
Toxicity proportional to zeta-potential
[134]
Salmonid cells
Nontoxic up to 1000 mg L
-1
[134]
NIPAM/BAM
D. magna
Proportional to reduction in
zeta-potential
[134]
PAMAM (5 nm)
Mouse
Kidney accumulation (possible renal
failure)
[15]
Chitosan
Human cells
Cell necrosis, LPO, ROS production
[135]
G5NH
2
PAMAM
Animal cells
Membrane damage EC
20
~500 nM
[136]
G7NH
2
PAMAM
Animal cells
Membrane damage EC
20
~50-150 nM
[136]
G5 Ac PAMAM
Animal cells
Nontoxic at 500 nM
[136]
Note:
LPO, lipid peroxidation; NIPAM, poly-
N
-isopropylacrylamide; NIPAM/BAM,
N
-isopropylacrylamide/
N
-
tert
-butylacrylamide copolymer nanoparticles; PAMAM, poly-
(amidoamine) dendrimers; G5 NH
2/
G7 NH
2
PAMAM, generation 5 (or 7) cationic
PAMAM (10-20 nm); G5 Ac PAMAM, generation 5 neutral PAMAM (5 nm diameter).
