Preparation and Characterization of a Novel Waterborne Lambda-Cyhalothrin/Alkyd Nanoemulsion

Fabrication and application of carrier-free and carrier-based nanopesticides in pest management

Pesticides are widely used for pest control to promote sustained and stable growth of agricultural production. However, indiscriminate pesticide usage poses a great threat to environmental and human health. In recent years, nanotechnology has shown the ability to increase the performance of conventional pesticides and has great potential for improving adhesion to crop foliage, solubility, stability, targeted delivery, and so forth. This review discusses two types of nanopesticides, namely, carrier-free nanopesticides and carrier-based nanopesticides, that can precisely release necessary and sufficient amounts of active ingredients. At first, the basic characterization and preparation methods of these two distinct types of nanopesticides are briefly summarized. Subsequently, current applications and future perspectives on scientific examples and strategies for promoting the usage efficacy and reducing the environmental risks of these nanopesticides were also described. Overall, nanopesticides can promote higher crop yields and lay the foundation for sustainable agriculture and global food security.

Harnessing the Carrier Solvent Complexity of Crop Biostimulant Liquid Formulations Using Locally Available Transesterified Waste Cooking Oil: Economic Recycling, Solvent Performance, and Bioefficacy Evaluation

Locally sourced waste cooking oil (WCO) was successfully base-catalyzed and transesterified with methanol into biodiesel to produce biostimulant (nitrobenzene) formulations and replace high-risk carrier solvents. Ideal synthesis conditions were composed of 1% NaOH, MeOH/oil molar ratio (6:1), reaction temperature (65 °C), a 3 h mixing rate, and 97-98% yields. Gas chromatography-mass spectrometry (GC-MS) analysis identified five fatty acid methyl esters (FAMEs) including palmitic, linoleic, oleic, stearic, and eicosenoic acids with high solubilization and olfactory characteristics. Using anionic and nonionic emulsifiers in conjunction with recycled biodiesel, a stable emulsifiable concentrate (NB 35% EC) was created with greater storage stability, wettability, and spreading capabilities than those of organic solvent-based ones. The highest counts of fruits per plant (35.80), flowers per plant (60.00), yield per plant (3.56 kg), and yield per hectare (143.7 quintals) were recorded in treatments with 4 mL/L biodiesel-based EC in field bioassays. In addition to having superior biosafety, FAME-based EC exhibits minimal phytotoxicity and is less harmful to aquatic creatures. It was discovered that the average cost-effectiveness was 5.49 times less expensive than solvent-based EC. In order to utilize waste oils as a locally obtained, sustainable alternative solvent with a wide solubilization range, low ecotax profile, circular economy, and high renewable carbon index, this integrative technique was expanded.

Analogous foliar uptake and leaf-to-root translocation of micelle nanoparticles in two dicot plants of diverse families

Bio-inspired nanoparticles, including metallic, micelles, and polymeric, have been explored as a novel tool in the quest for effective and safe agrochemicals. Although nanoparticles (NPs) are being rapidly investigated for their usefulness in agricultural production and protection, little is known about the behaviour and interaction of oil-in-water micelle nanoparticles or nano-micelles (NM) with plants. We loaded a bio-based resin inherent of tree from the Pinaceae family as active material and produced stable nano-micelles using a natural emulsifier system. Here, we show that foliar-applied nano-micelle can translocate in two dicot plants belonging to diverse families (Coriandrum sativum -Apiaceae and Trigonella foenumgraecum -Fabaceae) via similar mode. Fluorescent-tagged NM (average diameter 11.20nm) showed strong signals and higher intensities as revealed by confocal imaging and exhibited significant adhesion in leaf compared to control. The NM subsequently translocates to other parts of the plants. As observed by SEM, the leaf surface anatomies revealed higher stomata densities and uptake of NM by guard cells; furthermore, larger extracellular spaces in mesophyll cells indicate a possible route of NM translocation. In addition, NM demonstrated improved wetting-spreading as illustrated by contact angle measurement. In a field bioassay, a single spray application of NM offered protection from aphid infestation for at least 9 days. There were no signs of phytotoxicity in plants post-application of NM. We conclude that pine resin-based nano-micelle provides an efficient, safe, and sustainable alternative for agricultural applications.

Microfluidic preparation of a novel phoxim nanoemulsion pesticide against Spodoptera litura

With continuous development of pesticide dosage forms, emulsifiable concentrates using large amounts of organic solvents are gradually obsoleted. Nanoemulsions with high water content have been developed and the preparation processes also evolved, but these processes still exist some problems, such as poor controllability and high energy consumption. Microfluidic is a controllable nanoemulsion preparation system which mainly applied to pharmaceutical synthesis. In this study, the pesticide phoxim nanoemulsion was prepared by microfluidic technology. The optimized formulation of phoxim nanoemulsion was composed of Tween 80 and pesticide emulsifier 500 as surfactant, hexyl acetate as oil, and n-propanol as co-surfactant. Moreover, when the flow rates of water and oil in the microfluidic system were adjusted to 5 μL/min and 20 μL/min, phoxim nanoemulsion was obtained with a cloud point/boiling point of 109 °C, a particle size of 21.5 ± 0.8 nm and a potential value of - 18.7 ± 0.6 mV. Furthermore, the nanoemulsion had a rapid release effect in vitro which could be fitted by the Ritger-Peppas model. The feeding toxicity of the phoxim nanoemulsion was higher than that of commercial formulation while the contact killing effect was higher than that of the active ingredient. Therefore, pesticide dosage was reduced and the insecticidal effect was enhanced by using phoxim nanoemulsions. These results also confirm the potential of microfluidics as a green process to produce pesticide nanoemulsions.

PDA@Ti3 C2 Tx as a novel carrier for pesticide delivery and its application in plant protection: NIR-responsive controlled release and sustained antipest activity

BACKGROUND

Stimuli-responsive pesticide controlled release system provides a new strategy for the development of high-efficiency pesticides formulation.

RESULTS

In this article, we report a novel polydopamine surface modified MXene-Ti₃ C₂ T_x nanocarrier for pesticide delivery and plant protection. Polydopamine modified Ti₃ C₂ T_x (PDA@Ti₃ C₂ T_x ) nanocarrier was prepared by biomimetic self-polymerization of dopamine on the surface of Ti₃ C₂ T_x . A typical pesticide, emamectin benzoate (EB), was loaded on PDA@Ti₃ C₂ T_x through physisorption process, with a high pesticide loading rate of 45.37%. PDA@Ti₃ C₂ T_x exhibited excellent photothermal conversion effect (η = 34.5%). Under the irradiation of near-infrared (NIR) laser, EB would sustained release from PDA@Ti₃ C₂ T_x nanocarrier to surrounding medium. Compared with free EB, EB@PDA@Ti₃ C₂ T_x exhibited prolonged persistence period, which can keep antipest activity at 14 days post spraying. In addition, PDA@Ti₃ C₂ T_x nanocarrier and EB@PDA@Ti₃ C₂ T_x nanoformulation are of good safety, showing no side effect to the seed germination and seedling growth.

CONCLUSION

This research developed a novel nanocarrier for water-insoluble pesticide delivery, realizing NIR-responsive controlled release and sustained antipest activity.

Fabrication and evaluation of Lambda-Cyhalothrin nanosuspoemulsion with pH- and temperature-responsive based on polyethylene wax as carrier

Using polyethylene wax (PW) as the coating matrix, the lambda-cyhalothrin-PW nanosuspoemulsion (LC-PW) with a particle size of 80-150nm was prepared through high-speed stirring, hot melt emulsification and ultrasonic dispersion. The formulation and composition of the LC-PW were optimized, the morphology of the LC-PW was analyzed by dynamic light scattering (DLS) and TEM, and the structure of the LC-PW was characterized by UV and IR. The anti-photolysis test showed that LC-PW had a good anti-photolysis performance. Furthermore, LC-PW could sustainably release Lambda-cyhalothrin, which was pH- and temperature dependent. The insecticidal activity analysis in the greenhouse indicated that the toxic strength between LC-PW and LC-SC (lambda-cyhalothrin-suspension concentrate) to Mythimna separata was similar within the same concentration ranges tested, but the insecticidal duration of LC-PW was significantly longer than LC-SC. Thus, the new type of LC-PW with the properties of anti-photolysis and controlled release is suitable for application in the field as a better insecticide.

Highly Stable Waterborne Luminescent Inks Based on MAPbBr3@PbBr(OH) Nanocrystals for LEDs and Anticounterfeit Applications

Waterborne polymers are advantageous in terms of cost, convenience, sustainability, and environmental friendliness. As lead halide perovskite (LHP) nanocrystals suffer from fast degradation in the presence of water, it is challenging to encapsulate LHP nanocrystals in waterborne polymers. In this work, luminescent MAPbBr₃@PbBr(OH) nanocrystals were synthesized via the aqueous grinding process in the presence of 2-methyl-imidazole (2-MIM) and oleylamime (OAm). 2-MIM triggers the formation of the PbBr(OH) matrix, and OAm acts as a size-control ligand to control the size of MAPbBr₃@PbBrOH particles in the nanoscale range. Highly stable waterborne luminescent inks were successfully prepared by blending MAPbBr₃@PbBr(OH) nanocrystals with waterborne polymers, including poly(vinylpyrrolidone), poly(vinyl acetate), and acrylate resins. Owning to the dual protection of the polymer matrix and PbBr(OH) to LHP quantum dots (QDs), the luminescent films exhibit excellent stability to the environment under thermal and light irradiation. The ink can be used as a phosphor to fabricate down-converting green and white light-emitting diodes (LEDs). Waterborne anticounterfeiting inks suitable for screen printing were prepared via formula tuning for the anticounterfeit purpose. The anticounterfeiting luminescent patterns can be screen printed on paper, cloth, and poly(ethylene terephthalate) (PET), with encryption and decryption of information being accurately and conveniently realized by switching UV irradiation.

Development of abamectin-loaded nanoemulsion and its insecticidal activity and cytotoxicity

BACKGROUND

Owing to the advantages of high-efficiency, environmental protection and safety, nanoemulsions have become a highly popular water-insoluble pesticide delivery system in recent years.

RESULTS

In this study, abamectin-loaded nanoemulsion with remarkable physical stability and application performance was obtained by selecting the type and concentration of surfactant and the emulsification method. The optimal formula was 2% abamectin and 5% castor oil polyoxyethylene (EL-40) dissolved in 7.5% hydrocarbon solvent (S-200) made up to 100% with deionized water, which conformed to the quality indicators from the Food and Agriculture Organization (FAO) standards. Droplets on cabbage leaves showed a small dynamic contact angle, which ensured that the resulting nanoemulsion exhibited excellent wettability and diffusivity. Compared with emulsifiable concentrates (EC) and microemulsions (ME), the abamectin-loaded nanoemulsion had the lowest LC₅₀ (0.0686 mg L^-1 ) to third-instar larva of Plutella xylostella, causing the larval body to blacken and shrivel, which improved insecticidal activity. In addition, the abamectin-loaded nanoemulsion had low cytotoxicity. The viability of dendritic cells with added nanoemulsion reached 100% after 2 h, whereas that of cells with EC and ME was lower. After 24 h, the cell viability of dendritic cells with added ME was 0.

CONCLUSION

This research facilitated the design and fabrication of nanoemulsions for water-insoluble pesticide to enhance insecticidal activity, lower cytotoxicity and reduce environmental pollution. © 2020 Society of Chemical Industry.

Synthesis and Technology of Nanoemulsion-Based Pesticide Formulation

Declines in crop yield due to pests and diseases require the development of safe, green and eco-friendly pesticide formulations. A major problem faced by the agricultural industry is the use of conventional agrochemicals that contribute broad-spectrum effects towards the environment and organisms. As a result of this issue, researchers are currently developing various pesticide formulations using different nanotechnology approaches. The progress and opportunities in developing nanoemulsions as carriers for plant protection or nanodelivery systems for agrochemicals in agricultural practice have been the subject of intense research. New unique chemical and biologic properties have resulted in a promising pesticide nanoformulations for crop protection. These innovations-particularly the nanoemulsion-based agrochemicals-are capable of enhancing the solubility of active ingredients, improving agrochemical bioavailability, and improving stability and wettability properties during the application, thus resulting in better efficacy for pest control and treatment. All of these-together with various preparation methods towards a greener and environmentally friendly agrochemicals-are also discussed and summarized in this review.