Pesticides are an essential tool in integrated pest management. Nanopermethrin was prepared by solvent evaporation from an oil-in-water volatile microemulsion. The efficacy of the formulated nanopermethrin was tested against Aedes aegypti and the results compared to those of regular, microparticular permethrin. The 24 h LC50 for nanopermethrin and permethrin was found to be 0. 0063 and 0. 0199 mg/L, respectively. The formulated nanopermethrin was tested for toxicity against non-target organisms. Nanopermethrin did not show antibacterial activity against Escherichia coli (ATCC 13534 and 25922) or against Bacillus subtilis. Phytotoxicity studies of nanopermethrin to the seeds of Lycopersicum esculentum, Cucumis sativus, and Zea mays showed no restraint in root length and germination percentage. In the Allium cepa test, regular microparticular permethrin treatment of 0. 13 mg/L showed a mitotic index (MI) of 46. 8 % and chromosomal aberration of 0. 6 %, which was statistically significant (p &lt; 0. 05) compared to control. No significant differences were observed in 0. 13 mg/L nanopermethrin exposure as compared to control (MI of 52. 0 and 55. 03 % and chromosomal aberration of 0. 2 and 0 %, respectively). It was concluded that formulated nanopermethrin can be used as a safe and effectual alternative to commercially available permethrin formulation in agricultural practices. © 2012 Springer-Verlag.

Chandra Sekaran N

Centre for Nanobiotechnology

Vellore Campus

Amitava Mukherjee

Suresh Kumar R.S

Shiny P.J

Anjali C.H

Jerobin J

Goshen K.M

Magdassi S

Vellore Institute of Technology (VIT) is a private university located in&nbsp;Tamil Nadu, India. Founded in 1984, as Vellore Engineering College, the institution offers 20 undergraduate, 34 postgraduate, four integrated and four research programs. It has campuses in Vellore, Amravati, Bhopal and Chennai.

VIT is one of the top ranked private universities in India according to NIRF, THE and QS Rankings.&nbsp;Govt. of India has recognized&nbsp;VIT, Vellore as an&nbsp;Institution of Eminence. This has allowed VIT to take independent quality initiatives and move up in world ranking.

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VIT University

Environmental Science and Pollution Research

The rising threat of vector-borne diseases and environmental pollution has instigated the investigation of nanotechnology-based applications. The current study deals with a nanotechnological application involving the usage of nanometric pesticides such as permethrin nanoemulsion. The mean droplet diameter and zeta potential of the prepared permethrin nanoemulsion were found to be 12.4 ± 1.13 nm and -20.4 ± 0.56 mV, respectively. The temporal stability of permethrin nanoemulsion was found to be 4 days when checked in the external environment. The permethrin nanoemulsion exhibited LC50 values of 0.038 and 0.047 mgL-1 and 0.049 and 0.063 mgL-1 against larval and pupal stages of Culex tritaeniorhynchus and Aedes aegypti, respectively. The results obtained from the larvicidal and pupicidal assay were corroborated with the histopathological and biochemical profiles of hosts upon treatment with nanometric pesticide. Further, the biosafety studies of the nanopesticide were carried out against different non-target species like freshwater algae (Closterium), Cicer arietinum (Chickpea) and Danio rerio (Zebrafish), and the mosquitocidal concentration of nanopesticide was found to be non-toxic. The following study, therefore, describes the mosquitocidal efficacy of nanometric pesticide formulated in a greener approach, which can become a substitute for conventional pesticide application in an eco-benign manner.

Ecotoxicology and Environmental Safety

Enhanced mosquitocidal efficacy of colloidal dispersion of pyrethroid nanometric emulsion with benignity towards non-target species

The current eco-toxicological problem occurring world-wide as a result of the heavy usage of hazardous engineered nanomaterials has driven the invention or use of materials that are eco-safe. Nanomaterials prepared with an eco-safe approach provide a remedy for this problem. These engineered nanoparticles have a very small size range, which makes them both promising and challenging - a "two-edged sword." These nanoparticles are useful in product development, which is applicable in several fields. The properties of these nano-sized particles that make them a useful tool (e.g., shape, size, high reactivity), simultaneously make them a cause for concern in nature, resulting in ill-effects towards the environment. Bio-based nanoparticles are a better option with potent application properties and lower eco-toxicity influence. Bio-based nanoemulsions are an example of a bio-based nanomaterial. Nanoemulsions comprise an oil and aqueous phase mixed with a surfactant. A nanoemulsion can include nanoparticles ranging in size between 20 and 200 nm. The nanometric size of these emulsions allows for a wide range of applications in, for example, the pharmaceutical industry, cosmetics, and agriculture. Their bio-based approach to formulation makes them economical and eco-friendly. © Springer Nature Switzerland AG 2019. All Rights Reserved.

Handbook of Ecomaterials

Bio-Based Nanoemulsions: An Eco-Safe Approach Towards the Eco-Toxicity Problem

AbstractThe occurrence of pesticidal pollution in the environment and the resistance in the mosquito species makes an urge for the safer and an effective pesticide. Permethrin, a poorly water-soluble pyrethroid pesticide, was formulated into a hydrodispersible nanopowder through rapid solvent evaporation of pesticide-loaded oil in water microemulsion. Stability studies confirmed that the nanopermethrin dispersion was stable in paddy field water for 5 days with the mean particle sizes of 175.3 ± 0.75 nm and zeta potential of −30.6 ± 0.62 mV. The instability rate of the nanopermethrin particles was greater in alkaline (pH 10) medium when compared with the neutral (pH 7) and acidic (pH 4) dispersion medium. The colloidal dispersion at 45°C was found to be less stable compared with the dispersions at 25 and 5°C. The 12- and 24-h lethal indices (LC50) for nanopermethrin were found to be 0.057 and 0.014 mg l−1, respectively. These results were corroborative with the severity of damages observed in the mosquito larvae manifested in epithelial cells and the evacuation of the midgut contents. Further, the results were substantiated by the decrease in cellular biomolecules and biomarker enzyme activity in nanopermethrin treated larvae when compared to bulk and control treatment.

Bulletin of Entomological Research

Stability of nano-sized permethrin in its colloidal state and its effect on the physiological and biochemical profile of Culex tritaeniorhynchus larvae

Diethylphenylacetamide (Bulk-DEPA), an organic insect repellent was subjected to Poly(ethylene glycol) (PEG) polymerization followed by Phase Inversion Temperature (PIT) emulsification method to yield the polymeric nanodroplets of DEPA (Nano-DEPA). The mean hydrodynamic diameter was found to be 149 ± 1.06 nm. The efficacy of Bulk-DEPA and Nano-DEPA was comparatively investigated on the Culex quinquefasciatus mosquito population. The larvicidal bioassay was performed on the 1st, 2nd, and 3rd instar larvae of Culex quinquefasciatus and the median lethal indices (LC50) of was found to be 0.055, 0.208, 1.397 mg/L and 0.023, 0.144, 0.260 mg/L for Bulk-DEPA and Nano-DEPA respectively. The histopathological studies were found to be corroborative with the larvicidal bioassay. The median knockdown indices (KD50) on 2–3 day old sucrose fed adult mosquitoes determined by WHO cone bioassay and was found to be 55.168 and 33.277 mg/L for Bulk-DEPA and Nano-DEPA. The obtained results indicate the improved efficacy possessed by the Nano-DEPA as comparative to Bulk-DEPA even at lower concentrations. Further, the Nano-DEPA was impregnated onto the alginate cross-linked (ACL) and Plain (PL) cotton fabrics, and the Washing resistance index (WRI) was determined. The obtained results indicate the higher WRI possessed by the ACL cotton fabric than the PL cotton fabric. This was owing to the effective physical entrapment of Nano-DEPA onto the alginate matrices, which was further substantiated by high-resolution scanning electron microscopic (HR-SEM) studies. Overall, the present study has emphasized the benefit of formulating Bulk-DEPA into Nano-DEPA to exert higher efficacy on the mosquito population. In addition, study has provided the methodology for the effective impregnation of Nano-DEPA onto the cotton fabrics for the reliable application in long lasting insect repellent clothing. © 2017 The Authors

Fulltext

Journal of King Saud University - Science

Polymeric nanoencapsulation of insect repellent: Evaluation of its bioefficacy on Culex quinquefasciatus mosquito population and effective impregnation onto cotton fabrics for insect repellent clothing

Nanopesticides such as nanopermethrin can serve as an alternative to conventional pesticides causing eco-toxicity. The nanoformulation of this pyrethroid pesticide was carried out by solvent evaporation of pesticide-loaded microemulsion. The Z average for the nanopermethrin dispersion in paddy field water was found to be 169.2 ± 0.75 nm with a polydispersity index of 0.371 that exhibits uniform dispersion. Further, the nanopermethrin (NP) dispersion exhibited an effective stability in the paddy field water for a duration of 48 h with a Z average of 177.3 ± 1.2 nm and a zeta potential of −30.7 ± 0.9 mV. The LC50 of the nanopermethrin against Culex tritaeniorhynchus in the field condition was found to be 0.051 μg/mL. In addition to the stability assessment, the biosafety of the nanopermethrin was commenced on the beneficial bacterial isolate Enterobacter ludwigii (VITSPR1) considered as plant growth-promoting rhizobacteria. The toxic effect of nanopesticide was compared to its bulk counterpart, i.e. bulk permethrin (BP) at a concentration of 100 µg/mL, and the nanopesticide was found to be potentially safe. The results of biomarker enzymatic assays (lipid peroxidase, glutathione reductase, lactate dehydrogenase) displayed insignificant (p &lt; 0.05) toxicity of NP towards the bacterial cells compared to BP. The live–dead cell staining and SEM analysis illustrated negligible toxicity of NP towards the bacteria. The non-toxic behaviour of the NP towards the non-target species was studied which displayed the eco-safe property of NP. © 2016, Springer-Verlag Berlin Heidelberg.

Stability assessment of hydro dispersive nanometric permethrin and its biosafety study towards the beneficial bacterial isolate from paddy rhizome

The formulation of water dispersible nanopermethrin was investigated for its larvicidal property. Nanopermethrin was prepared using solvent evaporation of oil in water microemulsion, which was obtained by mixing an organic and aqueous phase. The mean particle size of nanodispersion in water was 151±27nm. X-ray diffraction (XRD) of nanopermethrin showed it was amorphous. Larvicidal studies were carried out against Culex quinquefasciatus and the results were compared with bulk permethrin. The LC50 of nanopermethrin to Cx quinquefasciatus was 0.117mg/L. The LC50 of bulk permethrin to Cx quinquefasciatus was 0.715mg/L. Nanopermethrin may be a good choice as a potent and selective larvicide for Cx. quinquefasciatus. © 2010 Elsevier Inc.

Formulation of water-dispersible nanopermethrin for larvicidal applications

Potential health and environmental effects of nanoparticles need to be thoroughly assessed before their widespread commercialization. Though there are few studies on cytotoxicity of nanoparticles on mammalian and human cell lines, there are hardly any reports on genotoxic and cytotoxic behavior of nanoparticles in plant cells. This study aims to investigate cytotoxic and genotoxic impacts of silver nanoparticles using root tip cells of Allium cepa as an indicator organism. A. cepa root tip cells were treated with four different concentrations (25, 20, 75, and 100 ppm) of engineered silver nanoparticles (below 100 nm size) dispersion, to study endpoints like mitotic index, distribution of cells in mitotic phases, different types of chromosomal aberrations, disturbed metaphase, sticky chromosome, cell wall disintegration, and breaks. For each concentration five sets of microscopic observations were carried out. No chromosomal aberration was observed in the control (untreated onion root tips) and the mitotic index (MI) value was 60.3%. With increasing concentration of the nanoparticles decrease in the mitotic index was noticed (60.30% to 27.62%). The different cytological effects including the chromosomal aberrations were studied in detail for the treated cells as well as control. We infer from this study that silver nanoparticles could penetrate plant system and may impair stages of cell division causing chromatin bridge, stickiness, disturbed metaphase, multiple chromosomal breaks and cell disintegration. The findings also suggest that plants as an important component of the ecosystems need to be included when evaluating the overall toxicological impact of the nanoparticles in the environment. © 2009 Elsevier B.V. All rights reserved.

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ISSN	0944-1344
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