Nanomaterials and nanotechnology for the delivery of agrochemicals: strategies towards sustainable agriculture.

Nanomaterials (NMs) have received considerable attention in the field of agrochemicals due to their special properties, such as small particle size, surface structure, solubility and chemical composition. The application of NMs and nanotechnology in agrochemicals dramatically overcomes the defects of conventional agrochemicals, including low bioavailability, easy photolysis, and organic solvent pollution, etc. In this review, we describe advances in the application of NMs in chemical pesticides and fertilizers, which are the two earliest and most researched areas of NMs in agrochemicals. Besides, this article concerns with the new applications of NMs in other agrochemicals, such as bio-pesticides, nucleic acid pesticides, plant growth regulators (PGRs), and pheromone. We also discuss challenges and the industrialization trend of NMs in the field of agrochemicals. Constructing nano-agrochemical delivery system via NMs and nanotechnology facilitates the improvement of the stability and dispersion of active ingredients, promotes the precise delivery of agrochemicals, reduces residual pollution and decreases labor cost in different application scenarios, which is potential to maintain the sustainability of agricultural systems and improve food security by increasing the efficacy of agricultural inputs.

Design and Synthesis of a Water-Based Nanodelivery Pesticide System for Improved Efficacy and Safety.

Developing an environmentally friendly and safe nanodelivery system is crucial to improve the efficacy of pesticides and minimize environmental and health risks. However, preparing a completely water-based nanopesticide without using harmful solvents is a technical challenge. In this study, a water-based nanodelivery pesticide system was constructed to improve the efficacy and safety of Emamectin Benzoate (EB). A specific surfactant, 29-(4-(5-hydroxynonan-5-yl)phenoxy)-3,6,9,12,15,18,21,24,27-nonaoxanonacosan-1-ol (SurEB) was designed and synthesized to form a water-based nanodelivery system (EBWNS) with EB. Molecular dynamics simulations revealed the self-assembly and interaction forces between SurEB and EB in water, providing insights into the formation mechanism of EBWNS nanoparticles. The nanodelivery system showed the prolonged effectivity of EB with reduced degradation and demonstrated a good control efficacy for multiple target pests, such as red spider mite, beet armyworm larvae (Lepidoptera: Noctuidae), and rice stem borers (Chilo suppressalis). Toxicology tests on various objects demonstrated that the EBWNS has low toxicity for seeds, HaCaT cells, zebrafish, earthworm, and E. coli. This study provides a distinctive perspective for developing environmentally friendly nanopesticide formulations, which clarified a water-based treatment method for specific lipid-soluble pesticides. The water-based nanodelivery pesticide system has the potential to improve the efficacy and safety of pesticides in the process of field applications.

Simple and fast colorimetric detection of lipopolysaccharide based on aptamer and SYBR Green I mediated aggregation of gold nanoparticles.

Lipopolysaccharide (LPS) poses a considerable threat to food safety and human health. A colorimetric assay for LPS detection based on LPS binding aptamer (LBA) and SYBR Green I (SG) mediated aggregation of gold nanoparticles (AuNPs) was established. In the absence of LPS, the LBA was absorbed onto the AuNPs surface which prevented SG-induced aggregation of AuNPs, and the sensing system exhibited red color. When LPS was added, it interacted with the LBA, forming a complex. At higher LPS concentration, many LBAs were exhausted resulting in SG-induced aggregation of AuNPs, and color change from red to blue. The range of colorimetric detection of LPS was linear in 0-12 EU/mL, with a limit of detection of 0.1698 EU/mL. Spiked LPS in real samples and interfering substances were also identified. This assay ingeniously using the fluorescent dye SG as an effective trigger of AuNPs aggregation, is rapid and facile than most of those earlier reported LBA-based LPS assays, and there is potential to be modified to construct assays for other targets.

Construction and characterization of ethyl cellulose-based nano-delivery system for phenamacril.

Fungicide-resistant Fusarium has become a threaten to wheat production. Novel fungicide formulations can improve the efficacy of active ingredient and minimize the emergence of resistance. Encapsulation of fungicides in biodegradable carriers, especially, in polysaccharide, is a feasible approach to develop environment-friendly and efficient formulation. This study focused on the synthesis of ethyl cellulose-based phenamacril nano-delivery system by combining emulsion-solvent evaporation and high-pressure homogenization technology to improve the control of fusarium head blight in wheat. Emulsifier 125 and Tersperse 2500 were screened from eleven commonly used surfactants. Emulsifier 125 and Tersperse 2500 in a ratio of 2:1 and phenamacril nanocapsules with the mean particle size of 152.5 ± 1.3 nm were prepared. These showed excellent storage stability and wettability on crop leaves. A bioassay comparing the nanocapsules with a commercial preparation against Fusarium graminearum showed significantly improved biological activity. This formulation could be used to effectively not only to control fusarium head blight but also delay the occurrence of resistance.

Temperature-Dependent Nanogel for Pesticide Smart Delivery with Improved Foliar Dispersion and Bioactivity for Efficient Control of Multiple Pests.

The use of nanomaterials and nanotechnology to construct a smart pesticide delivery system with target-oriented and controlled-release functions is important to increase the effective utilization rate and minimize environmental residue pollution. A temperature-dependent delivery system can modulate the release of pesticide with temperature to improve the efficacy and precision targeting. A series of poly(N-isopropylacrylamide) (PNIPAM)-based nanogels with high deformability and tunable structure were successfully constructed for smart pesticide delivery and effective pest control. A lambda-cyhalothrin (LC)-loaded Pickering emulsion (LC@TNPE) with a stable gel-like network structure was further formed by the temperature-dependent nanogel to encapsule the pesticide. The foliar wettability, photostability, and controlled-release property of LC@TNPE were effectively enhanced compared to the commercial formulation because of the encapsulation and stabilization of nanogel. The release rate of LC positively correlated with temperature changes and thereby adapted to the trend of pest population increase at higher temperature. The LC@TNPE displayed improved control efficacy on multiple target pests including Plutella xylostella, Aphis gossypii, and Pieris rapae compared with the commercial suspension concentrate and microcapsule suspension, and it showed marked efficacy to control Pieris rapae for an extended duration even at a 40% reduced dosage. Furthermore, the safety was evaluated systematically on cells in vitro and with a nontarget organism. Studies confirmed that the system was relatively safe for HepG2 cells and aquatic organism zebrafish. This research provides an insight into creating an efficient and environmentally friendly pesticide nanoformulation for sustainable agriculture production.

Preparation, Characterization, and Evaluation of Pyraclostrobin Nanocapsules by In Situ Polymerization.

In this study, pyraclostrobin nanocapsules were prepared by in situ polymerization with urea-formaldehyde resin as a wall material. The effects of different emulsifiers, emulsifier concentrations, and solvents on the physicochemical properties of pyraclostrobin nanocapsules were investigated. Solvesso™ 100 was selected as the solvent, and Emulsifier 600# was used as the emulsifier, which accounted for 5% of the aqueous phase system, to prepare pyraclostrobin nanocapsules with excellent physical and chemical properties. The particle size, ζ potential, and morphology of the nanocapsules were characterized by a particle size analyzer and transmission electron microscope. The nanocapsules were analyzed by Fourier-transform infrared spectroscopy, and the loading content and sustained release properties of the nanocapsules were measured. The results show that the size of the prepared nanocapsules was 261.87 nm, and the polydispersity index (PDI) was 0.12, presenting a uniform spherical appearance. The loading content of the pyraclostrobin nanocapsules was 14.3%, and their cumulative release rate was 70.99% at 250 h, providing better efficacy and sustainability compared with the pyraclostrobin commercial formulation.

Polylactic acid nanoparticles for co-delivery of dinotefuran and avermectin against pear tree pests with improved effective period and enhanced bioactivity.

Pesticide compounding technology for disease and pest control emerges as an effective way to increase the effectiveness of pesticides while reducing pesticides resistance. Nanomaterials and encapsulation technology have offered a new insight into preparing efficient pesticide formulations, especially constructing a co-delivery nanoparticle for synergistic pesticides. In this study, a dinotefuran/avermectin co-delivery nanoparticles (DACNPs) against pear tree pests with polylactic acid (PLA) as the wall material were constructed by double-emulsion method combined with high-pressure homogenization technique. The drug content of the DACNPs was 39.1% with an average size of 245.7 ± 4.2 nm and the mean polymer dispersity index (PDI) value was 0.123. The DACNPs showed high foliar retention and good spread performance on target leaves due to the nanoscale effect. The obtained DACNPs showed a better control effect on Grapholitha molesta Busck and Psylla chinensis Yang et Li compared with the commercial formulations, which could significantly prolong the effective duration and enhance the bioactivity with lower amounts and application frequency of pesticides. This study may provide new insights into developing novel pesticide formulations to improve the utilization rate of pesticides, reduce environmental pollution and minimize the cost of farming.

Advances in Controlled-Release Pesticide Formulations with Improved Efficacy and Targetability.

Pesticides are commonly used in modern agriculture and are important for global food security. However, postapplication losses due to degradation, photolysis, evaporation, leaching, surface runoff, and other processes may substantially reduce their efficacy. Controlled-release formulations can achieve the permeation-regulated transfer of an active ingredient from a reservoir to a target surface. Thus, they can maintain an active ingredient at a predetermined concentration for a specified period. This can reduce degradation and dissipation and other losses and has the potential to improve efficacy. Recent developments in controlled-release technology have adapted the concepts of intelligence and precision from the pharmaceutical industry. In this review, we present recent advances in the development of controlled-release formulations and discuss details of the preparation methods, material improvements, and application technologies.

Advances in Targeted Pesticides with Environmentally Responsive Controlled Release by Nanotechnology.

Pesticides are the basis for defending against major biological disasters and important for ensuring national food security. Biocompatible, biodegradable, intelligent, and responsive materials are currently an emerging area of interest in the field of efficient, safe, and green pesticide formulation. Using nanotechnology to design and prepare targeted pesticides with environmentally responsive controlled release via compound and chemical modifications has also shown great potential in creating novel formulations. In this review, special attention has been paid to intelligent pesticides with precise controlled release modes that can respond to micro-ecological environment changes such as light-sensitivity, thermo-sensitivity, humidity sensitivity, soil pH, and enzyme activity. Moreover, establishing intelligent and controlled pesticide release technologies using nanomaterials are reported. These technologies could increase pesticide-loading, improve the dispersibility and stability of active ingredients, and promote target ability.