Release kinetics of controlled release formulations of thiamethoxam employing nano-ranged amphiphilic PEG and diacid based block polymers in soil

Design and synthesis of silver nanoparticle anchored poly(ionic liquid)s mesoporous for controlled anticancer drug delivery with antimicrobial effect

Owing to the importance of drug delivery, the synthesis of advanced nanomaterials for targeted drug delivery plays a considerable role in medical treatment. One of the most prominent nanomaterials is PIL, which is used as controlled anticancer drug delivery and significantly improves the half-life and antitumor effect. In this study, a stable and effective drug carrier containing silver nanoparticles was reported for the drug delivery with an antimicrobial effect, and the capability of the drug carrier . PILP was synthesized by radical polymerization, and silver nanoparticles were anchored into PIL voids by in-situ reduction, which developed the adsorption antimicrobial effect and capability of the drug carrier. The synthesized nanocomposite was characterized. The Ag-PILP nanocomposite showed antibacterial activityagainst both E. coli and S. aureus with a MIC of 256 μg/mL, and bactericidal activity against E. coli and S. aureus strains with a MBC of 256 and 512 μg/mL, respectively.

Application of nanopesticides and its toxicity evaluation through Drosophila model

Insects feed on plants and cause the growth of plants to be restricted. Moreover, the application of traditional pesticides causes harmful effects on non-target organisms and poses serious threats to the environment. The use of conventional pesticides has negative impacts on creatures that are not the intended targets. It also presents significant risks to the surrounding ecosystem. Insects that are exposed to these chemicals eventually develop resistance to them. This review could benefit researcher for future development of nanopesticides research. This is because a holistic approach has been taken to describe the multidimensional properties of nanopesticides, health and environmental concerns and its possible harmful effects on non-target organisms and physiochemical entities. The assessment of effects of the nanopesticides is also being discussed through the drosophotoxicology. The future outlooks have been suggested to take a critical analysis before commercialization or formulation of the nanopesticides.

Nanopesticides: A Systematic Review of Their Prospects With Special Reference to Tea Pest Management

Background: Tea is a natural beverage made from the tender leaves of the tea plant (Camellia sinensis Kuntze). Being of a perennial and monoculture nature in terms of its cultivation system, it provides a stable micro-climate for various insect pests, which cause substantial loss of crop. With the escalating cost of insect pest management and increasing concern about the adverse effects of the pesticide residues in manufactured tea, there is an urgent need to explore other avenues for pest management strategies. Aim: Integrated pest management (IPM) in tea invites an multidisciplinary approach owing to the high pest diversity in the perennial tea plantation system. In this review, we have highlighted current developments of nanotechnology for crop protection and the prospects of nanoparticles (NPs) in plant protection, emphasizing the control of different major pests of tea plantations. Methods: A literature search was performed using the ScienceDirect, Web of Science, Pubmed, and Google Scholar search engines with the following terms: nanotechnology, nanopesticides, tea, and insect pest. An article search concentrated on developments after 1988. Results: We have described the impact of various pests in tea production and innovative approaches on the use of various biosynthesized and syntheric nanopesticides against specific insect pest targets. Simultaneously, we have provided support for NP-based technology and their different categories that are currently employed for the management of pests in different agro-ecosystems. Besides the broad categories of active ingredients (AI) of synthetic insecticides, pheromones and natural resource-based molecules have pesticidal activity and can also be used with NPs as a carriers as alternatives to traditional pest control agents. Finally, the merits and demerits of incorporating NP-based nanopesticides are also illustrated. Conclusions: Nanopesticides for plant protection is an emerging research field, and it offers new methods to design active ingredients amid nanoscale dimensions. Nanopesticide-based formulations have a potential and bright future for the development of more effective and safer pesticide/biopesticides.

Cellulose Nanocrystals Loaded with Thiamethoxam: Fabrication, Characterization, and Evaluation of Insecticidal Activity against Phenacoccus solenopsis Tinsley (Hemiptera: Pseudococcidae)

Using smart nanopesticide formulations based on nanomaterials can offer promising potential applications for decreasing pesticide residues and their effects on human health and the environment. In this study, a novel nanoformulation (NF) of thiamethoxam (TMX) was fabricated using the solvent evaporation method through loading TMX on cellulose nanocrystals (CNCs) as the carrier. The synthesized TMX-CNCs was investigated through different techniques, such as Fourier transform infrared spectrometer (FT-IR), X-ray diffraction (XRD), transmission electron microscopy (TEM), dynamic light scattering (DLS), and thermogravimetric analysis (TGA). The results revealed that the loading efficiency and entrapment efficiency were 18.7% and 83.7 ± 1.8% for TMX, respectively. The prepared nanoformulation (TMX-CNCs) had a width of 7-14 nm and a length of 85-214 nm with a zeta potential of -23.6 ± 0.3 mV. The drug release behavior study exhibited that the release of TMX from TMX-loaded CNCs was good and sustained. Furthermore, bioassay results showed that the insecticidal activity of TMX-CNCs against Phenacoccus solenopsis was significantly superior to that of the technical and commercial formulation, as indicated by the lower LC₅₀ value. The results indicate that the TMX nanoformulation has great potential for application in agriculture for pest control.

Nanocarriers for the Delivery of Medical, Veterinary, and Agricultural Active Ingredients

Nanocarrier-based delivery systems can be used to increase the safety and efficacy of active ingredients in medical, veterinary, or agricultural applications, particularly when such ingredients are unstable, sparingly soluble, or cause off-target effects. In this review, we highlight the diversity of nanocarrier materials and their key advantages compared to free active ingredients. We discuss current trends based on peer-reviewed research articles, patent applications, clinical trials, and the nanocarrier formulations already approved by regulatory bodies. Although most nanocarriers have been engineered to combat cancer, the number of formulations developed for other purposes is growing rapidly, especially those for the treatment of infectious diseases and parasites affecting humans, livestock, and companion animals. The regulation and prohibition of many pesticides have also fueled research to develop targeted pesticide delivery systems based on nanocarriers, which maximize efficacy while minimizing the environmental impact of agrochemicals.

Amphiphilic polymer based nanoformulations of mancozeb for management of early blight in tomato

Controlled release (CR) nanoformulations of Mancozeb (Manganese-zinc double salt of N, N-bisdithiocarbamic acid), a protective fungicide, have been developed using poly (ethylene glycols) (PEGs) based functionalized amphiphilic copolymers and evaluated for the management of early blight in tomato. During the field experiment, it was observed that number of infected leaflets/plants were less in developed formulation treated plants as compared to commercial products. Number of infected leaflets per plant was 2.40-4.60 and the number of fruits per plant were 6.40-9.00 at 50 mg L^-1, whereas at 100 mg L^-1, the corresponding numbers were 2.10-4.10 and 6.30-9.10 respectively. These formulations can be used to optimize the release of Mancozeb to achieve disease control for the desired period depending upon the matrix of the polymer used. Importantly, sufficient amount of active ingredient remains available for a reasonable period of time after application leading to reduced number of applications of pesticide.

A critical evaluation of nanopesticides and nanofertilizers against their conventional analogues

Among a wide range of possible applications of nanotechnology in agriculture, there has been a particular interest in developing novel nanoagrochemicals. While some concerns have been expressed regarding altered risk profile of the new products, many foresee a great potential to support the necessary increase in global food production in a sustainable way. A critical evaluation of nanoagrochemicals against conventional analogues is essential to assess the associated benefits and risks. In this assessment, recent literature was critically analysed to determine the extent to which nanoagrochemicals differ from conventional products. Our analysis was based on 78 published papers and shows that median gain in efficacy relative to conventional products is about 20-30%. Environmental fate of agrochemicals can be altered by nanoformulations, but changes may not necessarily translate in a reduction of the environmental impact. Many studies lacked nano-specific quality assurance and adequate controls. Currently, there is no comprehensive study in the literature that evaluates efficacy and environmental impact of nanoagrochemicals under field conditions. This is a crucial knowledge gap and more work will thus be necessary for a sound evaluation of the benefits and new risks that nanoagrochemicals represent relative to existing products.

Development Strategies and Prospects of Nano-based Smart Pesticide Formulation

Pesticides are important inputs for enhancing crop productivity and preventing major biological disasters. However, more than 90% of pesticides run off into the environment and reside in agricultural products in the process of application as a result of the disadvantages of conventional pesticide formulation, such as the use of a harmful solvent, poor dispersion, dust drift, etc. In recent years, using nanotechnology to create novel formulations has shown great potential in improving the efficacy and safety of pesticides. The development of nano-based pesticide formulation aims at precise release of necessary and sufficient amounts of their active ingredients in responding to environmental triggers and biological demands through controlled release mechanisms. This paper discusses several scientific issues and strategies regarding the development of nano-based pesticide formulations: (i) construction of water-based dispersion pesticide nanoformulation, (ii) mechanism on leaf-targeted deposition and dose transfer of pesticide nanodelivery system, (iii) mechanism on increased bioavailability of nano-based pesticide formulation, and (iv) impacts of nanoformulation on natural degradation and biosafety of pesticide residues.

Initial stage of the degradation of three common neonicotinoids: theoretical prediction of charge transfer sites

Tautomerization of acetamiprid gives alternatives to search new pathways for its degradation in water.

Eco-friendly PEG-based controlled release nano-formulations of Mancozeb: Synthesis and bioefficacy evaluation against phytopathogenic fungi Alternaria solani and Sclerotium rolfsii

Controlled release (CR) nano-formulations of Mancozeb (manganese-zinc double salt of N,N-bisdithiocarbamic acid), a protective fungicide, have been prepared using laboratory-synthesized poly(ethylene glycols) (PEGs)-based functionalized amphiphilic copolymers without using any surfactants or external additives. The release kinetics of the developed Mancozeb CR formulations were studied and compared with that of commercially available 42% suspension concentrate and 75% wettable powder. Maximum amount of Mancozeb was released on 42nd day for PEG-600 and octyl chain, PEG-1000 and octyl chain, and PEG-600 and hexadecyl chain, on 35th day for PEG-1000 and hexadecyl chain, on 28th day for PEG-1500 and octyl chain, PEG-2000 and octyl chain, PEG-1500 and hexadecyl chain, and PEG-2000 and hexadecyl chain in comparison to both commercial formulations (15th day). The diffusion exponent (n value) of Mancozeb in water ranged from 0.42 to 0.62 in tested formulations. The half-release (t_1/2) values ranged from 17.35 to 35.14 days, and the period of optimum availability of Mancozeb ranged from 18.54 to 35.42 days. Further, the in vitro bioefficacy evaluation of developed formulations was done against plant pathogenic fungi Alternaria solani and Sclerotium rolfsii by poison food technique. Effective dose for 50% inhibition in mgL^-1 (ED₅₀) values of developed formulations varied from 1.31 to 2.79 mg L^-1 for A. solani, and 1.60 to 3.14 mg L^-1 for S. rolfsii. The present methodology is simple, economical, and eco-friendly for the development of environment-friendly CR formulations of Mancozeb. These formulations can be used to optimize the release of Mancozeb to achieve disease control for the desired period depending upon the matrix of the polymer used. Importantly, the maximum amount of active ingredient remains available for a reasonable period after application. In addition, the developed CR formulations were found to be suitable for fungicidal applications, allowing use of Mancozeb in lower doses.

Dissipation dynamics of clothianidin and its control efficacy against Bradysia odoriphaga Yang and Zhang in Chinese chive ecosystems

BACKGROUND

Clothianidin is a second-generation neonicotinoid insecticide that is quite effective against Bradysia odoriphaga Yang and Zhang, the major insect pest affecting Chinese chive in northern China. In this study, the dissipation of clothianidin in soil and its residue in leaves and pseudostems/bulbs as well as its control efficacy against B. odoriphaga and two other secondary pests were investigated in Chinese chive fields after soil application of clothianidin by the directional spray-washing method.

RESULTS

The half-life of clothianidin was 35.73-36.10 days, and it could be detected in Chinese chive plants in both treatment plots up to 240 days after a single soil application. Clothianidin applied at 3.0 and 6.0 kg AI ha(-1) could suppress B. odoriphaga population growth, achieve satisfactory levels of pest control for almost 10 months and reduce the losses of the yield in winter. Moreover, the treatments also significantly reduced Thrips alliorum and Acrolepia alliella populations up to nearly 180 days after one application.

CONCLUSION

Clothianidin can be considered to show long-lasting efficacy against B. odoriphaga and to be safe for use in Chinese chive at 3.0 and 6.0 kg AI ha(-1) once in the early root-rearing period to control B. odoriphaga in these cultivation ecosystems. © 2015 Society of Chemical Industry.

Nanoencapsulation, Nano-guard for Pesticides: A New Window for Safe Application

The application of nanotechnology in pesticide delivery is relatively new and in the early stages of development. This technology aims to reduce the indiscriminate use of conventional pesticides and ensure their safe application. This critical review investigated the potential of nanotechnology, especially the nanoencapsulation process for pesticide delivery. In-depth investigation of various nanoencapsulation materials and techniques, efficacy of application, and current research trends are also presented. The focus of ongoing research was on the development of a nanoencapsulated pesticide formulation that has slow releasing properties with enhanced solubility, permeability, and stability. These properties are mainly achieved through either protecting the encapsulated active ingredients from premature degradation or increasing their pest control efficacy for a longer period. Nanoencapsulated pesticide formulation is able to reduce the dosage of pesticides and human exposure to them, which is environmentally friendly for crop protection. However, lack of knowledge of the mechanism of synthesis and lack of a cost-benefit analysis of nanoencapsulation materials hindered their application in pesticide delivery. Further investigation of these materials' behavior and their ultimate fate in the environment will help the establishment of a regulatory framework for their commercialization. The review provides fundamental and critical information for researchers and engineers in the field of nanotechnology and especially the use of nanoencapsulation techniques to deliver pesticides.

Neonicotinoids in the Canadian aquatic environment: a literature review on current use products with a focus on fate, exposure, and biological effects

Developed to replace organophosphate and carbamate insecticides, neonicotinoids are structurally similar to nicotine. The three main neonicotinoid insecticides, imidacloprid, clothianidin, and thiamethoxam, are being re-evaluated by Health Canada's Pest Management Regulatory Agency (PMRA). An important aspect of the re-evaluation is the potential for effects in non-target organisms, including aquatic organisms. Leaching into surface waters is one of the major concerns surrounding extensive use of neonicotinoids, especially in close proximity to water bodies. The PMRA has classified IMI as 'persistent' with a 'high' leaching potential. Globally, neonicotinoids have been detected in a variety of water bodies, typically at concentrations in the low μg/L range. While IMI has been included in some monitoring exercises, there are currently very few published data for the presence of CLO and THM in Canadian water bodies. The majority of neonicotinoid toxicity studies have been conducted with IMI due to its longer presence on the market and high prevalence of use. Aquatic insects are particularly vulnerable to neonicotinoids and chronic toxicity has been observed at concentrations of IMI below 1 μg/L. Acute toxicity has been reported at concentrations below 20 μg/L for the most sensitive species, including Hyalella azteca, ostracods, and Chironomus riparius. Fish, algae, amphibians, and molluscs are relatively insensitive to IMI. However, the biological effects of THM and CLO have not been as well explored. The Canadian interim water quality guideline for IMI is 0.23 μg/L, but there is currently insufficient use, fate, and toxicological information available to establish guidelines for CLO and THM. Based on concentrations of neonicotinoids reported in surface waters in Canada and globally, there is potential for aquatic invertebrates to be negatively impacted by neonicotinoids. Therefore, it is necessary to address knowledge gaps to inform decisions around guidelines and registration status for neonicotinoid insecticides in Canada to protect our aquatic ecosystems.

Advanced treatment of cephalosporin pharmaceutical wastewater by nano-coated electrode and perforated electrode

The objective of this study was to investigate the degradation of nonbiodegradable organic pollutants in biologically cephalosporin pharmaceutical wastewater using different electrodes such as non-nano-scale electrode (traditional coated), nano-scale (nano-coated) electrode, and perforated electrode after biotreatment. The traditional coated electrode plate, nano-coated electrode plate, and two different perforated titanium dioxide (TiO2) electrode plates with an average pore size of 10 μm and 20 μm were chosen as the anode. The results demonstrated that traditional coated electrode, nano-scale electrode, and perforated electrode could effectively remove nonbiodegradable organic pollutants from pharmaceutical wastewater. The perforated electrode with an average pore size of 10 μm exhibited the best degradation effect with a 90 % decrease in the chemical oxygen demand (COD) (COD content reduced from 320 mg L(-1) to 32 mg L(-1)). During catalytic degradation, the electrical conductivity of pharmaceutical wastewater increased and the pH increased and finally reached equilibrium. It was also found that the perforated TiO2 electrode produced relatively large amounts of dissolved oxygen during the catalytic oxidation process, reaching above 4 mg L(-1), whereas the nano-coated electrode produced little dissolved oxygen. The biotoxicities of all wastewater samples increased firstly then decreased slightly during the electrical catalytic oxidation, but the final biotoxicities were all higher than initial ones.

Application of poly(epsilon-caprolactone) nanoparticles containing atrazine herbicide as an alternative technique to control weeds and reduce damage to the environment

Nanoparticles of poly(epsilon-caprolactone) containing the herbicide atrazine were prepared, characterized, and evaluated in terms of their herbicidal activity and genotoxicity. The stability of the nanoparticles was evaluated over a period of three months, considering the variables: size, polydispersion index, pH, and encapsulation efficiency. Tests on plants were performed with target (Brassica sp.) and non-target (Zea mays) organisms, and the nanoparticle formulations were shown to be effective for the control of the target species. Experiments using soil columns revealed that the use of nanoparticles reduced the mobility of atrazine in the soil. Application of the Allium cepa chromosome aberration assay demonstrated that the nanoparticle systems were able to reduce the genotoxicity of the herbicide. The formulations developed offer a useful means of controlling agricultural weeds, while at the same time reducing the risk of harm to the environment and human health.

Nanopesticide research: current trends and future priorities

The rapid developments in nanopesticide research over the last two years have motivated a number of international organizations to consider potential issues relating to the use of nanotechnology for crop protection. This analysis of the latest research trends provides a useful basis for identifying research gaps and future priorities. Polymer-based formulations have received the greatest attention over the last two years, followed by formulations containing inorganic nanoparticles (e.g., silica, titanium dioxide) and nanoemulsions. Investigations have addressed the lack of information on the efficacy of nanopesticides and a number of products have been demonstrated to have greater efficacy than their commercial counterparts. However, the mechanisms involved remain largely unknown and further research is required before any generalizations can be made. There is now increased motivation to develop nanopesticides that are less harmful to the environment than conventional formulations, and future investigations will need to assess whether any promising products developed are able to compete with existing formulations, in terms of both cost and performance. Investigations into the environmental fate of nanopesticides remain scarce, and the current state of knowledge does not appear to be sufficient for a reliable assessment to be made of their associated benefits and risks. A great deal of research will therefore be required over the coming years, and will need to include (i) the development of experimental protocols to generate reliable fate properties, (ii) investigations into the bioavailability and durability of nanopesticides, and (iii) evaluation of current environmental risk assessment approaches, and their refinement where appropriate.