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.

Chandra Sekaran N

Centre for Nanobiotechnology

Vellore Campus

Amitava Mukherjee

Mishra P

Balaji A.P.B

Dhal P.K

Suresh Kumar R.S

Magdassi S

Margulis K

Tyagi B.K

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

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

Bulletin of Entomological 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 present study deals with the preparation and optimisation of neem oil nanoemulsion by microfluidization process and its application for the bacterial infection management in aquaculture. The effect of process parameters like surfactant concentration (Tween 20, Tween 80), homogenisation pressure and the number of cycles on the droplet size of neem oil nanoemulsion was investigated. The optimized pressure and number of cycles for the neem oil nanoemulsion preparation was found to be 20,000 psi and 25 cycles respectively. A significant decrease (p &lt; 0.05) in the particle size of neem oil nanoemulsion was observed as the pressure, number of cycles and concentration of surfactant increase. The neem oil nanoemulsion prepared using 1:3 ratio of neem oil and Tween 80 surfactant showed a good stability with a mean droplet size of 24.5 ± 1.33 nm. The concentration of Azadiractin, an active ingredient in neem oil nanoemulsion was found to be 21.187 ± 1.01 μg/mL. The 1:3 ratio of neem oil - Tween 80 formulated nanoemulsion showed good antibacterial activity against the fish pathogen, Aeromonas culicicola (MIC of 0.93 μl/mL). The morphological changes inflicted by the neem nanoemulsion treatment on bacterial cells were evident from the scanning electron microscopy and membrane integrity analysis. Further, the In-vivo bactericidal efficacy of the neem oil nanoemulsion was tested on Common carp (Cyprinus carpio). The neem oil nanoemulsion treatment exhibited protective action against Aeromonas culicicola infection and it improved the antioxidant defence system of fish. The above results envisage the use of neem oil nanoemulsion as a potential alternative for synthetic antibiotics in treatment of bacterial infection of the fish. Copyright © 2018 John Wiley &amp; Sons, Ltd.

Flavour and Fragrance Journal

Nanometric neem oil emulsification through microfluidization, and its therapeutic potential againstAeromonas culicicolainfection inCyprinus carpio

Mosquitoes, being a vector for some potentially dreadful diseases, pose a considerable threat to people all around the world. The control over the growth and propagation of mosquitoes comprises conventional pesticides, insect growth regulators and other microbial control agents. However, the usage of these common chemicals and conventional pesticides eventually has a negative impact on human health as well as the environment, which therefore becomes a major concern. The lacuna allows nanotechnology to come into action and exploit nanopesticides. Nanopesticides are majorly divided into two categories—synthetic and biological. Several nanoformulations serve as a promising nanopesticide viz. nanoparticles, e.g. biologically synthesised nanoparticles through plant extracts, nanoemulsions prepared using the essential oils like neem oil and citronella oil and nanoemulsion of conventional pesticides like pyrethroids. These green approaches of synthesising nanopesticides make use of non-toxic and biologically derived compounds and hence are eco-friendly with a better target specificity. Even though there are numerous evidences to show the effectiveness of these nanopesticides, very few efforts have been made to study the possible non-target effects on other organisms prevalent in the aquatic ecosystem. This study focuses on the role of these nanopesticides towards the vector control and its eco-safe property against the other non-target species. © 2017, Springer-Verlag GmbH Germany.

Environmental Science and Pollution Research

Biological nanopesticides: a greener approach towards the mosquito vector control

The increasing risk of vector-borne diseases and the environmental pollution in the day-to-day life due to the usage of the conventional pesticides makes the role of nanotechnology to come into the action. The current study deals with one of the applications of nanotechnology through the formulation of neem urea nanoemulsion (NUNE). NUNE was formulated using neem oil, Tween 20, and urea using the microfluidization method. Prior to the development of nanoemulsion, the ratio of oil/surfactant/urea was optimized using the response surface modeling method. The mean droplet size of the nanoemulsion was found to be 19.3 ± 1.34 nm. The nanoemulsion was found to be stable for the period of 4 days in the field conditions which aids to its mosquitocidal activity. The nanoemulsion exhibited a potent ovicidal and larvicidal activity against A. aegypti and C. tritaeniorhynchus vectors. This result was corroborated with the histopathological analysis of the NUNE-treated larvae. Further, the effect of NUNE on the biochemical profile of the target host was assessed and was found to be efficacious compared to the bulk counterpart. The nanoemulsion was then checked for its biosafety towards the non-target species like plant beneficial bacterium (E. ludwigii), and phytotoxicity was assessed towards the paddy plant (O. sativa). Nanometric emulsion at the concentration used for the mosquitocidal application was found to be potentially safe towards the environment. Therefore, the nanometric neem-laced urea emulsion tends to be an efficient mosquito control agent with an environmentally benign property.

Environmentally benign nanometric neem-laced urea emulsion for controlling mosquito population in environment

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

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

Permethrin, a poorly water-soluble synthetic pesticide belonging to the pyrethroid family, was formulated into water-dispersive nanometric form by rapid evaporation of pesticide loaded oil-in-water microemulsion. The mean hydrodynamic diameter of Nanopermethrin was found to be 199.01 ± 1.4 nm. The efficacy of the Nanopermethrin was comparatively investigated with its bulk form against 2-3 days old adult mosquitoes by WHO cone bioassay for 60 min. The median knockdown concentration of Culex tritaeniorhynchus, Culex quinquefasciatus and Aedes albopictus were found to be 7.20 × 10(4), 7.53 × 10(4), 0.42 × 10(3) mg/L for Bulk permethrin, and 0.98 × 10(4), 1.17 × 10(4), 0.05 × 10(3) mg/L for Nanopermethrin, respectively. The obtained results extrapolate the improved efficacy of Nanopermethrin even at low-level concentrations. Hence, the formulated Nanopermethrin will serve as an effective alternative pesticide in controlling the mosquito population with reduced environmental toxicity.

Bulletin of Environmental Contamination and Toxicology

The Environmentally Benign form of Pesticide in Hydrodispersive Nanometric form with Improved Efficacy Against Adult Mosquitoes at Low Exposure Concentrations

The utilization of increased dosage of insect repellents to overcome mosquito resistance has raised environmental concerns globally. In accord to this, we have formulated an efficacious, water-dispersive, nanometric formulation of a poor water-soluble insect repellent, diethylphenylacetamide (DEPA) by poly(ethylene glycol) (PEG) polymerization followed by PIT emulsification method. The critical micelle concentration of PEG in the spontaneously emulsified conventional DEPA droplets was determined, based on the droplets physical stability. Subjecting them to PIT emulsification yielded monodispersed polymeric nanomicelles of DEPA (Nano DEPA) with hydrodynamic mean diameter of 153.74. nm. The high-resolution scanning and transmission electron microscopic studies revealed the characteristic core-shell structure of micelle. The comparative efficacy of Bulk DEPA and Nano DEPA was evaluated by larvicidal and WHO cone bioassay against the Japanese encephalitis vector Culex tritaeniorhynchus. The median lethal concentrations (48. h) for 3rd instars C. tritaeniorhynchus larvae were found to be 0.416. mg/L for Bulk DEPA and 0.052. mg/L for Nano DEPA, respectively. The median knockdown concentrations (60. min) for the two to three-day-old, sucrose-fed, female adult mosquitoes were 5.372% (v/v) and 3.471% (v/v) for Bulk and Nano DEPA, respectively. Further investigation by histopathological and biochemical studies propound that Nano DEPA exerted better bioefficacy as comparative to its bulk form even at minimal exposure concentrations. Hence, Nano DEPA will serve as an effective alternate in controlling the vector expansion with reduced dosage. © 2015 Elsevier B.V.

Colloids and Surfaces B: Biointerfaces

Nanoformulation of poly(ethylene glycol) polymerized organic insect repellent by PIT emulsification method and its application for Japanese encephalitis vector control

AbstractFilariasis is a mosquito-borne disease that causes lymphedema and the main vector is Culex quinquefasciatus. A simple measure was taken to eradicate the vector using nanoemulsion. Eucalyptus oil nanoemulsion was formulated in various ratios comprising of eucalyptus oil, tween 80 and water by ultrasonication. The stability of nanoemulsion was observed over a period of time and 1:2 ratios of eucalyptus oil (6%) and surfactant (12%) was found to be stable. The formulated eucalyptus oil nanoemulsion was characterized by transmission electron microscopy and dynamic light scattering. The nanoemulsion droplets were found to have a Z-average diameter of 9.4 nm and were spherical in shape. The larvicidal activity of eucalyptus oil nanoemulsion and bulk emulsion was tested and compared. Our nanoemulsion showed higher activity when compared to bulk emulsion. The histopathology of larvae-treated and untreated nanoemulsion was analyzed. Furthermore, biochemical assays were carried out to examine the effect of nanoemulsion on biochemical characteristics of larvae. The treated larval homogenate showed decrease in total protein content and a significant reduction in the levels of acetylcholinesterase. The levels of acid and alkaline phosphatase also showed reduction as compared to control larval homogenate.

Fulltext

Nanoemulsion of eucalyptus oil and its larvicidal activity against Culex quinquefasciatus

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.

Distinctive effects of nano-sized permethrin in the environment

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

Journal	Data powered by TypesetBulletin of Entomological Research
Publisher	Data powered by TypesetCambridge University Press (CUP)
ISSN	0007-4853
Open Access	0