الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
Development of nanopesticides has been increased for the competition with the conventional formulations, in terms of efficiency, cost, safety, and minimal residual amount.
There are 3500 pyrethroid and pyrethrin products registered in the United States, many of which are encapsulated formulations and are consumed globally. Contamination by these formulations in surface water and residues on consumed crops are plausible.
The toxicological investigations of nano pesticides will allow the precautions for the application of any product coming to markets in the near future.
Pyrethroids have become a top choice for household pest control. Deltamethrin(DM), a type II synthetic pyrethroid, is widely used as an insecticide due to its low environmental persistence and toxicity. DM is successfully substituted for organophosphates in pest-control programs and has been used for the treatment of mosquito nets to control malaria and vector borne diseases all over the world. So, human exposure to DM is becoming increasingly common widespread. The negative effects of DM on hematological, urinary and respiratory systems have previously been reported. DM exposure leads to the pathophysiology of a broad spectrum of cerebrovascular and neurodegenerative diseases.
Chitosan NPs and silica NPs were synthesized , deltamethrin conjugated with chitosan NPs and silica NPs to produce chitosan loaded deltamethrin (CS/DM Nps) and silica loaded deltamethrin (S/DM Nps) and used against disease vectors, such as mosquito. The acute toxicity of DM, CS/DM Nps and S/DM Nps in male albino rats was assessed. First, the dynamic light scattering technique verified the hydrodynamic size of CS/DM Nps and S/DM Nps (568.3± 15.36 nm and 284.6 ± 11.23nm respectively) and the negative Zeta potential value (−12.5 mV and −20.8 mV respectively). Deltamethrin encapsulation efficiency was found to be 87.031% in CS/DM Nps and 93.739% in S/DM Nps. Second, CS/DM Nps and S/DM Nps were exposed to mosquito(Culex pipiens larvae) for a 24 h bioassay and the results were compared with the bulk deltamethrin. The LC50 of CS/DM Nps, S/DM Nps and deltamethrin was found to be 0.5718 mg/L, 0.0186 mg/L and 0.3388 mg/L, respectively. Third, The median lethal dose of DM, CS/DM Nps, and S/DM Nps was calculated using Dixon’s up-and-down method (38.55 mg/kg, 304.438 mg /kg, and 87.95 mg/kg respectively). The acute toxicity was evaluated at 14 d after oral administration of DM at 25.35, 32.95 and 42.84 mg/kg, CS/DM Nps at 217.20, 282.36 and 367.06 mg/kg and S/DM Nps at 57.8, 75.13, and 97.68 mg/kg.
Studies on neurotoxicity and genotoxicity of the subchronic exposure to nano insecticides have been investigated. Male albino rats were divided into four groups. group I: control group; group II received DM dissolved in corn oil 3.855 mg/kg BW; group III received S/DM Nps 8.795 mg/kg BW. group IV: received CS/DM Nps 30.44 mg/kg BW. All treatments were given orally for four weeks. The DM group showed a highly significant elevation in MDA content, monoamine oxidase, acetylcholinesterase, and vascular endothelial growth factor activity, chromosome aberrations, and expression level of neurogenic genes, JAK2 and STAT3. DM upregulated the JAK/STAT pathway. Loading DM with silica or encapsulation with chitosan Nps appears to have a mitigating effect on the transcription responses caused by deltamethrin exposure alone.The ratio of polychromatic erythrocytes to the normochromatic erythrocytes proved that DM had a strong cytotoxic effect on the bone marrow cells than CS/DM Nps and S/DM Nps groups. These neuronal alterations were evidenced by the deficiency in memory and learning behaviors and the histopathological findings of the hippocampus and the cortex. Behavioral data declared that DM induced anxiogenic effect on rats. This is expressed by the increased freezing time, stretch attend posture, and frequency in the open field maze. DM impaired short-term memory in rats. Loading DM with silica or chitosan Nps could not ameliorate the DM effect in memory.
The S/DM Nps and CS/DM Nps can be used as an effective larivicide at low concentrations and a safe alternative to DM with minimal environmental impacts. The nano formulations containing DM were less toxic than the free one. The use of nanocarriers reduced the damage to health and environment.