Biodegradable polymer based encapsulation of neem oil nanoemulsion for controlled release of Aza-A

Direct measurement of surface interactions experienced by sticky microcapsules made from environmentally benign materials

We present a study combining experimental measurements, theoretical analysis, and simulations to investigate core-shell microcapsules interacting with a solid boundary, with a particular focus on understanding the short-range potential energy well arising from the tethered force. The microcapsules, fabricated using a Pickering emulsion template with a cinnamon oil core and calcium alginate shell, were characterized for size (∼5-6μm in diameter) and surface charge (∼-20mV). We employed total internal reflection microscopy and particle tracking to measure the microcapsule-boundary interactions and diffusion, from which potential energy and diffusivity profiles were derived. The potential energy profile characterizing the normal interaction was analyzed and simulated by considering electrostatic, gravitational, van der Waals, and tethered forces, while the lateral diffusivity was compared to that of a solid particle-boundary interaction, inclusive of hydrodynamic forces. The diffusivity was represented as a normalized diffusion coefficient to eliminate the impact of fluid viscosity. The normalized diffusion coefficient of polymer-shell microcapsules (∼0.02) was found to be an order of magnitude smaller than that of solid polystyrene particles (∼0.2). The microcapsule sampled a potential well consisting of two distinct minima, as observed experimentally and supported by analytical expressions and Brownian dynamics simulations. A critical tethered height hct=46.3nm and the alginate radius of rg=32.1nm were obtained from fitting our model to experimental data. This work concludes that these benign core-shell microcapsules interact with a nearby boundary via a transient tethering interaction, overall producing a mild 'sticky' interaction that would likely be beneficial for applications in consumer products.

Investigating the wettability of neem oil nanoemulsion as a green pesticide on leaf surfaces - optimizing formulation, assessing stability, and enhancing wettability

The present study focuses on formulating a stable green oil-in-water nanoemulsion (NE) formulation for pesticide application, thereby addressing the primary challenges of botanical pesticides by improving the stability, efficacy, and wettability of leaf surfaces. Neem oil and rhamnolipid biosurfactant were utilized as the base oil and surfactant, respectively for the NE formulation. Initial screening studies with varying oil-to-surfactant ratios identified an optimal ratio of 7.13 (w/w), corresponding to 15% oil (v/v) of total emulsion volume, for a stable NE. The stability of the formulation was validated in a 25 mL volume over 20 days, maintaining a mean droplet diameter of 139.1 ± 7.34 nm and a polydispersity index of 0.207. Further stability assessments under varying time, temperature, ionic strengths, and centrifugal forces revealed a relatively stable droplet diameter ranging from 141 to 245 nm. The surface tension for the optimal formulation was measured to be 35.7 ± 0.4 mN m-1. Additionally, experiments with various NE formulations on selected leaves showed that NEs with higher oil content displayed faster spreading, as indicated by a rapid reduction in contact angle. The novelty of the study lies in demonstrating the synergistic interaction between oil and rhamnolipid, which facilitated faster spreading compared to the individual spreading of either component, as revealed by the dynamic spreading studies of the NE formulation on leaf surfaces. Therefore, this research paves the way for future research and development of green pesticides that are sustainable and effective compared to their chemical counterparts.

Development and characterization of nanoemulsions containing Lippia origanoides Kunth essential oil and their antifungal potential against Candida albicans

AIMS

Nanoemulsions based on plant essential oils have shown promise as alternatives against fungal pathogens by increasing the solubility and bioavailability of the active compounds of essential oils, which can improve their efficacy and safety. In the present study, we aimed to prepare and characterize nanoemulsions of Lippia origanoides essential oil, and analyze their antifungal activity against C. albicans in planktonic and biofilm form. Additionally, we sought to verify their cytotoxicity.

METHODS AND RESULTS

Alginate nanoemulsions were prepared with different concentrations of essential oil, sunflower oil, and surfactant to investigate ideal formulations regarding stability and antifungal efficiency. The results showed the nanoemulsions remained stable for longer than 60 days, with acidic pH, particle sizes ranging from 180.17 ± 6.86 nm to 497.85 ± 253.50 nm, zeta potential from -60.47 ± 2.25 to -43.63 ± 12, and polydispersity index from 0.004 to 0.622. The photomicrographs revealed that the addition of sunflower oil influenced the formation of the particles, forming nanoemulsions. The antifungal results of the essential oil and nanoemulsions showed that the MIC ranged from 0.078 to 0.312 mg ml-1. The nanoemulsions were more effective than the free essential oil in eradicating the biofilm, eliminating up to 89.7% of its mass. With regard to cytotoxicity, differences were found between the tests with VERO cells and red blood cells, and the nanoemulsions were less toxic to red blood cells than the free essential oil.

CONCLUSIONS

These results show that nanoemulsions have antifungal potential against strains of C. albicans in planktonic and biofilm forms.

A review on the encapsulation of "eco-friendly" compounds in natural polymer-based nanoparticles as next generation nano-agrochemicals for sustainable agriculture and crop management

Crop management techniques and sustainable agriculture offer a comprehensive farming method that incorporates social, economic, and ecological factors. Sustainable agriculture places a high priority on soil health, water efficiency, and biodiversity conservation in order to develop resilient and regenerative food systems that can feed both the current and future generations. Our goal in this review is to give a thorough overview of current developments in the use of polysaccharides as raw materials for the encapsulation of natural chemicals in nanoparticles as novel crop protection products. The search for recent research articles and latest reviews has been carried out through pubmed, google scholar, BASE as search engines. Offer cutting-edge solutions for sustainable crop management that satisfy the demands of an expanding population, comply with changing legal frameworks, and address environmental issues by encasing natural compounds inside polysaccharide-based nanoparticles. A variety of natural substances, such as essential oils, plant extracts, antimicrobials compounds and miRNA, can be included in these nanoparticles. These materials have many advantages, such as biocompatibility, biodegradability and controlled release of active compounds. Thanks to their action mechanism, they are able to mediate hormone signaling and gene expression in different plant physiological aspects, as well as enhance their tolerance to abiotic stress conditions. Sustainable agriculture can be supported by this type of treatments, correctly developing food safety through the production of non-toxic nanoparticles, low-cost industrial scale-up and the use of biodegradable materials. Polysaccharide-based nanoparticles have a wide range of uses in agriculture: they improve crop yields, encourage "eco-friendly" farming methods and can decrease the concentrations of active ingredient used, providing an accurate and affective dosage without damaging further species, as well as avoiding treatment resistance risks. These nanoparticles can also reduce the negative effects of chemical fertilizers and pesticides, contributing to the environmentally friendly agricultural development. Furthermore, the application of polysaccharide-based nanoparticles is consistent with the expanding trend of green and sustainable agriculture.

Characterization of Acid-Responsive-Release Matrine/ZIF-8@Sodium Alginate Microcapsules Prepared by Electrostatic Spray and Their Application in the Control of Soybean Cyst Nematode

Matrine (MT) is a kind of alkaloid extracted from Sophora and is a promising substitute for chemical nematicides and botanical pesticides. The present study utilized sodium alginate (SA), zeolite imidazole salt skeleton (ZIF), and MT as raw materials to prepare a pH-response-release nematicide through the electrostatic spray technique. Zinc metal-organic framework (ZIF-8) was initially synthesized, followed by the successful loading of MT. Subsequently, the electrostatic spray process was employed to encapsulate it in SA, resulting in the formation of MT/ZIF-8@SA microcapsules. The efficiency of encapsulation and drug loadings can reach 79.93 and 26.83%, respectively. Soybean cyst nematode (SCN) is one of the important pests that harm crops; acetic acid produced by plant roots and CO2 produced by root respiration causing a decrease in the pH of the surrounding environment, which is most attractive to the SCN when the pH is between 4.5 and 5.4. MT/ZIF-8@SA releases the loaded MT in response to acetic acid produced by roots and acidic oxides produced by root respiration. The rate of release was 37.67% higher at pH 5.25 compared with pH 8.60. The control efficiency can reach 89.08% under greenhouse conditions. The above results demonstrate that the prepared MT/ZIF-8@SA not only exhibited excellent efficacy but also demonstrated a pH-responsive release of the nematicide.

Spontaneous nanoemulsification of cinnamon essential oil: Formulation, characterization, and antibacterial and antibiofilm activity against fish spoilage caused by Serratia rubidaea BFMO8

The contemporary food industry's uses of nanoemulsions (NEs) include food processing, effective nutraceutical delivery, the development of functional chemicals, and the synthesis of natural preservatives, such as phytocompounds. Although cinnamon essential oil (CEO) is widely used in the cosmetic, pharmaceutical, and food industries, it is difficult to add to aqueous-based food formulations due to its weak stability and poor water solubility. This study describes the formulation of a CEO nanoemulsion (CEONE) by spontaneous emulsification and evaluates its antibacterial and antibiofilm properties against biofilm-forming Serratia rubidaea BFMO8 isolated from spoiled emperor fish (Lethrinus miniatus). Bacteria causing spoilage in emperor fish were isolated and identified as S. rubidaea using common morphological, cultural, and 16S RNA sequencing methods, and their ability to form biofilms and their susceptibility to CEONE were assessed using biofilm-specific methods. The spontaneous emulsification formulation of CEONE was accomplished using water and Tween 20 surfactant by manipulating organic and aqueous phase interface properties and controlling particle growth by capping surfactant increases. The best emulsification, with highly stable nano-size droplets, was accomplished at 750 rpm and a 1:3 ratio concentration. The stable CEONE droplet size, polydispersity index, and zeta potential values were 204.8 nm, 0.115, and -6.05 mV, respectively. FTIR and high-resolution liquid chromatography-mass spectrometry (HR-LCMS) analyses have revealed carboxyl, carbonyl, and phenol-like primary phytochemical functional groups in CEO and CEONE, which contribute to their antibacterial and antibiofilm properties.

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.

OPTIMIZATION AND CHARACTERIZATION OF ESSENTIAL OILS FORMULATION FOR ENHANCED STABILITY AND DRUG DELIVERY SYSTEM OF MEFLOQUINE

Objective: This work aims to choose suitable essential oil formulations to improve the bioavailability and long-term aqueous stability of mefloquine in drug delivery systems. Methods: Oil phases of pomegranate oil, black cumin seed oil, and garlic oil. To choose the proper oil and surfactant for creating pseudo-ternary phase diagrams, cremophore EL, tween®20 and tween®80 (surfactants), and brij 35 (co-surfactants) were used in a variety of concentrations and combinations (Smix). Mefloquine was estimated to be soluble in a variety of oils, surfactants, and co-surfactants. Drug solubility, drug release research, thermodynamic stability, mean hydrodynamic size and zeta potential. Results: Garlic with smix of cremophore EL and brij 35, Pomegranate with Tween 2.0, and Black cumin seed oil with Tween 80 showed the highest solubilization and emulsification capabilities and were further investigated using ternary phase diagrams. When combined with the co-surfactants under investigation, cremophore EL demonstrated a greater self-emulsification zone than tween® 80 and tween 20. Garlic oil, cremophore EL, and brij 35 nanoemulsion showed smaller size, greater zeta potential, less emulsification time, high transmittance, and better drug solubility than microemulsion formulations on especially those made with tween®20 and tween 80. Mefloquine loaded garlic oil nanoemulsion showed considerably low release in body fluid (32.48%) and a good release in intestinal fluid (82.78%) by 12 h in a drug release study. Conclusion: Garlic oil as the oil phase and a mixture of cremophore EL and brij 35 as the surfactant phase are ideal surfactants and co-surfactant for mefloquine loaded garlic oil nanoemulsion with greater drug release in release kinetics investigation.

Alginate Based Core-Shell Capsules Production through Coextrusion Methods: Recent Applications

Encapsulation is used in various industries to protect active molecules and control the release of the encapsulated materials. One of the structures that can be obtained using coextrusion encapsulation methods is the core-shell capsule. This review focuses on coextrusion encapsulation applications for the preservation of oils and essential oils, probiotics, and other bioactives. This technology isolates actives from the external environment, enhances their stability, and allows their controlled release. Coextrusion offers a valuable means of preserving active molecules by reducing oxidation processes, limiting the evaporation of volatile compounds, isolating some nutrients or drugs with undesired taste, or stabilizing probiotics to increase their shelf life. Being environmentally friendly, coextrusion offers significant application opportunities for the pharmaceutical, food, and agriculture sectors.

Multi-drug loaded eugenol-based nanoemulsions for enhanced anti-mycobacterial activity

Tuberculosis is one of the oldest bacterial infections known to mankind caused by Mycobacterium tuberculosis. The aim of this research is to optimize and formulate a multi-drug loaded eugenol based nanoemulsion system and to evaluate its ability as an antimycobacterial agent and its potential to be a low cost and effective drug delivery system. All the three eugenol based drug loaded nano-emulsion systems were optimized using response surface methodology (RSM)-central composite design (CCD) and were found stable at a ratio of 1 : 5 (oil : surfactant) when ultrasonicated for 8 minutes. The minimum inhibitory concentration (MIC) values against strains of Mycobacterium tuberculosis highly proved that these essential oil-based nano-emulsions showed more promising results and an even improved anti-mycobacterium activity on the addition of a combination of drugs. The absorbance of 1st line anti-tubercular drugs from release kinetics studies showed a controlled and sustained release in body fluids. Thus, we can conclude that this is a much more efficient and desirable method in treating infections caused by Mycobacterium tuberculosis and even its MDR/XDR strains. All these nano-emulsion systems were stable for more than 3 months.

Core-shell micro/nanocapsules: from encapsulation to applications

Encapsulation is the way to wrap or coat one substance as a core inside another tiny substance known as a shell at micro and nano scale for protecting the active ingredients from the exterior environment. A lot of active substances, such as flavours, enzymes, drugs, pesticides, vitamins, in addition to catalysts being effectively encapsulated within capsules consisting of different natural as well as synthetic polymers comprising poly(methacrylate), poly(ethylene glycol), cellulose, poly(lactide), poly(styrene), gelatine, poly(lactide-co-glycolide)s, and acacia. The developed capsules release the enclosed substance conveniently and in time through numerous mechanisms, reliant on the ultimate use of final products. Such technology is important for several fields counting food, pharmaceutical, cosmetics, agriculture, and textile industries. The present review focuses on the most important and high-efficiency methods for manufacturing micro/nanocapsules and their several applications in our life.

Effects of black cumin-based antimalarial drug loaded with nano-emulsion of bovine and human serum albumins by spectroscopic and molecular docking studies

The growing understanding of nanoemulsion biomedical applications necessitates a basic understanding of protein-drug-loaded nanoemulsion interaction. In our present study, we investigated the binding interactions of Mefloquine (MEF)-loaded black cumin seed oil (Thymoquinone) nanoemulsion of different concentrations towards human and bovine serum albumin (HSA&BSA).Fluorescenceemission,three-dimensionalspectra,UV-visible spectroscopy, and FTIR-spectroscopy, techniques were used together with molecular docking studies to identify the binding effects. The ground state complex formation between Mefloquine-loaded black cumin seed oil nanoemulsion and protein fluorophores was confirmed by a decrease in fluorescence intensity and disputed hyper-chronicity found in the UV-visible spectra of albumins. According to three-dimensional fluorescence spectral analysis, the addition of MEF in thymoquinone impacted the microenvironment around aromatic amino acid (tryptophan and tyrosine) residues in HSA. The quenching mechanism is determined to be static contact by stern-volmer analysis, resulting in the formation of a stable bioconjugate. Significant modifications in the amide FTIR frequencies at around 1600 cm-1 correlate to variations in the secondary alpha-helical structures of biomolecules at the MEF-loaded nanoemulsion interface. Molecular dynamic studies have shown the binding affinity scores of the proteins BSA and HSA with the drug, MEF-loaded black cumin seed oil nanoemulsion. The determined thermodynamic parameters were found to agree with molecular docking data, indicating that vander-waals and hydrogen bonding forces were important in the interaction process. MEF prefers a highly polar binding site at the exterior area of domains in HSA than BSA, as shown in the molecular model, and the hydrogen bonds are highlighted. From our results, we have observed that drug delivery has a detrimental effect on protein frame confirmation by altering its physiological function.

Nanoencapsulation application to prolong postharvest shelf life

This review offers our opinion on current and future trends regarding nanoencapsulation interventions to extend postharvest shelf life of stored grains, fruits, and vegetables. Herein, we considered two major factors influencing postharvest shelf life for comments: aerobic food spoilage microorganisms and stored pests. Nanoemulsions, edible/active coatings, and nanopackaging loading essential oils as antimicrobial, antioxidant, or pesticide showed promising results in prolonged shelf life at room/cold storage without compromising quality, organoleptic properties, and postharvest physiology. Trends with nanoencapsulation using plant-based pesticides as agrochemical-free methods to keep produce fresh longer were commented as potential candidates for prolonging the shelf life of stored grains and fruits at the postharvest stage. Research with potential large-scale feasibility is intensive, but safety assessment is required and remains little explored.

Formulation and characterisation of Azadirachta indica nanobiopesticides for ecofriendly control of wheat pest Tribolium castaneum and Rhyzopertha dominica

This study aimed to formulate the green, sustainable, and ecofriendly nanobiopesticides of Azadirachta indica with enhanced pest control efficacy. Nanoprecipitation method was used for the development of nanobiopesticides. Optimisation was done by response surface methodology. Nanoformulations were characterised by zetasizer, scanning electron microscopy, energy dispersive x-ray spectroscopy, atomic force microscopy, and Fourier transform infrared spectroscopy. Pesticidal potential of nanosuspensions was evaluated by insecticide impregnated filter paper method. Optimised nanobiopesticide showed an average particle size of 275.8 ± 0.95 nm, polydispersity index (PDI) 0.351 ± 0.002, and zeta potential of -33 ± 0.90 mV. Nanobiopesticides exhibited significantly higher mortality rates of 86.81 ± 3.04 and 84.97 ± 2.83% against Tribolium castaneum and Ryzopertha dominica, respectively, as compared to their crude extract. Minor change in particle size from 275.8 ± 0.95 to 298.8 ± 1.00 nm and PDI from 0.351 ± 0.002 to 0.445 ± 0.02 were observed after 3 months of storage at 4 °C. Pesticidal efficacy of A. indica was significantly enhanced by the formulation of its nanobiopesticides.

Novel Biopesticides Based on Nanoencapsulation of Azadirachtin with Whey Protein to Control Fall Armyworm

Biopesticides have become a global trend in order to minimize the hazards derived from synthetic chemical pesticides and improve the safety, efficacy, and environmental friendliness of agricultural pest management. Herein, we report a novel biopesticide composite encapsulating azadirachtin with the size of 260.9 ± 6.8 nm and its effects on the insect pest Spodoptera frugiperda (fall armyworm). The nanocomposite biopesticide was produced via nano emulsification and freeze-drying process using whey protein isolate as a nanocarrier matrix to encapsulate azadirachtin, a natural insect-killing compound obtained from neem seed. We found that the nanocomposite biopesticide acted quicker and with greater efficacy than bulk azadirachtin treatment with corresponding LC₅₀ values within 11 days of S. frugiperda larvae survival. Through confocal microscopy, we found the enhanced biodistribution of the nanocomposite to all parts of the insect body. Photodegradation assays revealed an enhanced UV stability facilitated by light-scattering stemming from the intrinsic nanostructure and UV scavenging vitamin-E component.

Study on the preparation of sustained-release thiamethoxam microspheres by blending microcrystalline wax with tapioca starch ester or dehydroabietic acid ester as the matrix

The controlled release formulations (CRFs) are considered an effective way to solve damage to the environment caused by traditional pesticide formulations. To change the defects of traditional neonicotinoid formulations that dissolve quickly in soil, three types of thiamethoxam (TM) CRFs microspheres with content of 20% TM were prepared using microcrystalline wax (MK) as the matrix, laurate acid tapioca starch ester (MSK) and stearyl dehydroabietic acid ester (MDK) as the regulators of ingredient release. The release behavior of CRFs microspheres in water and soil showed that the microspheres had superior stability and different TM sustained-release periods, and TM release of the microspheres in soil was faster than that in water. The release rate is TM/MDK > TM/MSK > TM/MK. In water, the release of thiamethoxam technical was finished after 38 hours. However, for TM/MK, the release rate was 94% after 240 hours, and the release time was extended by 6 times. Meanwhile, TM/MDK has a particular pH-responsive release. Research shows that using microcrystalline wax as the matrix, by adding MSK or MDK to adjust the release of ingredients, pesticide CRFs microspheres with different release periods can be prepared to achieve the purpose of controlling the release of pesticides.

Efficacy of Mandarin Crust Oil, Marigold Extract and Their Nanoemulsions, on Spodoptera littoralis (Boisd.) Larvae

<b>Background and Objective:</b> In recent years, nanoemulsions have been used to target pest toxicity due to the dangers of chemical pesticides. The current study investigated the insecticidal activity of the mandarin crust oil (<i>Citrus reticulata</i>) and marigold extract (<i>Calendula officinalis </i>L.) in the form of nanoemulsions formulations and plant oil against 2nd instars larvae of <i>Spodoptera littoralis</i>. (Boisduval). <b>Materials and Methods:</b> To assess the toxicity of treatments to 2nd instar larvae, the leaf-dipping technique was used. The toxicity was recorded after one, three, five and seven days post-treatment and LC<sub>50</sub> values were calculated. <b>Results:</b> The results indicated that nanoemulsion of plant oil extracts has the highest insecticidal activity against <i>S. littoralis</i>, followed by plant oil extracts. The major constituents identified by GC-MS analysis in marigold extract and mandarin crust oil were, 6-epi-shyobunol (Longiborneol) and D-Limonene, respectively. Furthermore, at LC<sub>50</sub>, all treatments decreased AST/GOT and ALT/GPT activity, showing a significant reduction in creatinine activity when compared to control. <b>Conclusion:</b> According to the current study, the use of the nanoemulsion formulation could be useful in integrated pest management programs.

Eco-Friendly Castor Oil-Based Delivery System with Sustained Pesticide Release and Enhanced Retention

The deposition of pesticides and their retention on plant surfaces are critical challenges for modern precision agriculture, which directly affect phytosanitary treatment, bioavailability, efficacy, and the loss of pesticides. Herein, a novel and eco-friendly waterborne polyurethane delivery system was developed to enhance the spray deposition and pesticide retention on plant surfaces. More specifically, biobased cationic and anionic waterborne polyurethane dispersions were synthesized from castor oil. Both cationic and anionic polyurethane dispersions exhibited remarkable microstructural, amphiphilic, and nanoparticle morphologies with a core-shell structure that served to encapsulate a biopesticide (azadirachtin) in their hydrophobic cores (WPU-ACT). The results indicated that the cationic WPU-ACT carriers exhibited a better sustained release behavior and a better protective effect from light and heat for azadirachtin. In addition, the simultaneous spray of anionic and cationic WPU-ACT significantly enhanced the spray deposition and prolonged the retention of pesticides due to the reduced surface tension and surface precipitation induced by the electrostatic interaction when two droplets with opposite charges come into contact with each other. A field efficacy assessment also indicated that the simultaneous spray of anionic and cationic WPU-ACT could control the infestation of brown planthopper in rice crops. Castor oil-based waterborne polyurethanes in this study work as an efficient pesticide delivery system by exhibiting enhanced deposition, rainfastness, retention ability, protection, and sustained release behavior, holding great promise for spraying pesticide formulations in modern and environmentally friendly agricultural applications.

Advances in controlled release pesticide formulations: Prospects to safer integrated pest management and sustainable agriculture

As the world is striving hard towards sustainable agricultural practices for a better tomorrow, one of the primary focuses is on effective pest management for enhanced crop productivity. Despite newer and potent chemicals as pesticides, there are still substantial crop losses, and if by any means this loss can be tackled; it will alleviate unwanted excessive use of chemical pesticides. Scientific surveys have already established that pesticides are not being utilized by the crops completely rather a significant amount remains unused due to various limiting factors such as leaching and bioconversion, etc., resulting in an adverse effect on human health and ecosystems. Concerted efforts from scientific diaspora toward newer and innovative strategies are already showing promise, and one such viable approach is controlled release systems (CRS) of pesticides. Moreover, to bring these smart formulations within the domain of current pesticide regulatory framework is still under debate. It is thus, paramount to discuss the pros and cons of this new technology vis-à-vis the conventional agrarian methods. This review deliberates on the developmental updates in this innovative field from the past decades and also appraises the challenges encumbered. Additionally, critical information and the foreseeable research gaps in this emerging area are highlighted.

Porous starch citrate biopolymer for controlled release of carbofuran in the management of root knot nematode Meloidogyne incognita

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Starch bio-polymer is a promising material in controlled release formulations for Meloidogyne incognita management.

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The porous starch and starch citrate bio-polymer was prepared and characterised with FTIR, SEM and TGA.

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The SEM revealed highly stabilized biopolymers and the TGA showed increased thermal stability of the materials, while the FTIR confirmed successful synthesis of the bio-polymer.

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Effective control was achieved with porous starch citrate.

The undesirable environmental impacts of inappropriate application of pesticides have brought about research into new matrices for controlled release of pesticides. Porous starch citrate biopolymer was designed for the release of carbofuran in this experiment and characterized using Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM) and Thermo-Gravimetric Analysis (TGA) for functional group, surface morphology and thermal stability properties respectively. The SEM revealed highly stabilized porous starch citrate biopolymers with porous structures and gradients suitable for controlled release studies. The transmittance bands at 3347, 1714 and 1073 cm⁻¹ for OH, CO and COC— Created by potrace 1.16, written by Peter Selinger 2001-2019 ]]>—— stretching vibrations further confirms the successful synthesis of the biopolymer. TGA showed an increase in the thermal stability after citric acid modification with one-step decomposition from 290 ^ᵒC to 500 ^ᵒC. From Korsemeyer-Peppas model, the carbofuran-porous starch citrate (CBFN/PRS/STH/CTRT) followed a lower diffusion release model with gradual increment in all the quantity of carbofuran loaded. An accelerated rate of diffusion percentage was seen in direct application of carbofuran. Egg hatch and mortality of juveniles were recorded on daily basis for seven days. Direct application of carbofuran (CBFN/DRT) and carbofuran-porous starch citrate biopolymer gave the best results with significant (p < 0.05) reduction in egg hatch and higher percentage mortality. The rate of release of carbofuran from the starch citrate bio polymer matrix was significantly lower than the direct application, and in spite of the slow rate of release, higher juvenile mortality and reduction in egg hatch was achieved.

Cytotoxic, antioxidant and antibacterial activities of copper oxide incorporated chitosan-neem seed biocomposites

In this study biopolymer-inorganic material of chitosan‑copper oxide-neem seed (CS-CuO-NS) biocomposite was successfully synthesized by simple precipitation method and characterized by FT-IR, XRD, HR-SEM, TEM and TGA analyses. From HR-SEM and TEM analysis, CS-CuO-NS biocomposite shows flower and needle like structure respectively. The size of the as prepared CS-CuO-NS biocomposite is found to be 20-100 nm. All the synthesized materials were tested for antibacterial activity against both gram positive like Staphylococcus aureus (S. aureus) and Streptococcus pyogenes (S. pyogenes) and gram negative like Escherichia coli (E. coli) and Klebsiella aerogenes (K. aerogenes) bacterial strains. The maximum zone of inhibition is obtained for CS-CuO-NS biocomposite against S. aureus (23 mm), S. pyogenes (21 mm), E. coli (22 mm) and K. aerogenes (20 mm). The minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) were determined. The antioxidant activity was determined by free radicals scavenging such as 1, 1-Diphenyl-2-picryhydrazyl (DPPH) and 2, 2-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS). Furthermore, the cytotoxicity effect was investigated against human breast cancer (MCF-7) cell line and the highest cytotoxicity (IC₅₀:16.33 μg/mL) is found to be in biocomposite. From the results of antibacterial, antioxidant and cytotoxic activities, it is concluded that CS-CuO-NS biocomposite may be suitable for biomedical applications.

Formulation and evaluation of norcanthridin nanoemulsions against the Plutella xylostella (Lepidotera: Plutellidae)

Background

Norcantharidin (NCTD), a demethylated derivative of cantharidin (defensive toxin of blister beetles), has been reported to exhibit insecticidal activity against various types of agricultural pests. However, NCTD applications are limited by its poor water solubility and high dosage requirement. Nanoemulsions have attracted much attentions due to the transparent or translucence appearance, physical stability, high bioavailability and non-irritant in nature. In general, nanoemulsions with small droplet size can enhance the bioavailability of drugs, whereas this phenomenon is likely system dependent. In present study, NCTD nanoemulsions were developed and optimized to evaluate and improve the insecticidal activity of NCTD against Plutella xylostella (Lepidotera: Plutellidae) by a spontaneous emulsification method.

Results

Triacetin, Cremophor EL and butanol were selected as the constituents of NCTD nanoemulsions via solubility determination, emulsification efficiency and ternary phase diagram construction. Insecticidal activity of NCTD nanoemulsion was associated with the content of surfactant and cosurfactant: (1) Higher effective toxicity exhibited at Smix (surfactant to cosurfactant mass ratio) = 3:1 that may be associated with the changes in interfacial tension; (2) NCTD nanoemulsion at 3:7 < SOR (surfactant to oil mass ratio) < 6:4 was more effective at lower surfactant level, which was attributed to the relatively slow diffusion rate of NCTD hindering by excess surfactant. Interestingly, nanoemulsions with smaller droplets were not found to be more effective in our study.

Conclusions

The optimized NCTD nanoemulsion (triacetin/Cremophor EL/butanol (60/20/20, w/w)) exhibited effective insecticidal activity (LC₅₀ 60.414 mg/l, LC₉₀ 185.530 mg/l, 48 h) than the NCTD acetone solution (LC₅₀ 175.602 mg/L, LC₉₀ 303.050 mg/L, 48 h). Spontaneous emulsifying nanoemulsion employed to formulate this poor water-soluble pesticide is a potential system for agriculture application.

Electronic supplementary material

The online version of this article (10.1186/s12896-019-0508-8) contains supplementary material, which is available to authorized users.

Development of an attract-and-kill co-formulation containing Saccharomyces cerevisiae and neem extract attractive towards wireworms

BACKGROUND

Wireworms (Coleoptera: Elateridae) are major insect pests of worldwide relevance. Owing to the progressive phasing-out of chemical insecticides, there is great demand for innovative control options. This study reports on the development of an attract-and-kill co-formulation based on Ca-alginate beads, which release CO₂ and contain neem extract as a bioinsecticidal compound. The objectives of this study were to discover: (1) whether neem extract can be immobilized efficiently, (2) whether CO₂ -releasing Saccharomyces cerevisiae and neem extract are suitable for co-encapsulation, and (3) whether co-encapsulated neem extract affects the attractiveness of CO₂ -releasing beads towards wireworms.

RESULTS

Neem extract was co-encapsulated together with S. cerevisiae, starch and amyloglucosidase with a high encapsulation efficiency of 98.6% (based on measurement of azadirachtin A as the main active ingredient). Even at enhanced concentrations, neem extract allowed growth of S. cerevisiae, and beads containing neem extract exhibited CO₂ -emission comparable with beads without neem extract. When applied to the soil, the beads established a CO₂ gradient of >15 cm. The co-formulation containing neem extract showed no repellent effects and was attractive for wireworms within the first 24 h after exposure.

CONCLUSION

Co-encapsulation of S. cerevisiae and neem extract is a promising approach for the development of attract-and-kill formulations for the control of wireworms. This study offers new options for the application of neem extracts in soil. © 2017 Society of Chemical Industry.

Oil encapsulation in core-shell alginate capsules by inverse gelation II: comparison between dripping techniques using W/O or O/W emulsions

In the first part of this article, it was described an innovative method of oil encapsulation from dripping-inverse gelation using water-in-oil (W/O) emulsions. It was noticed that the method of oil encapsulation was quite different depending on the emulsion type (W/O or oil-in-water (O/W)) used and that the emulsion structure (W/O or O/W) had a high impact on the dripping technique and the capsules characteristics. The objective of this article was to elucidate the differences between the dripping techniques using both emulsions and compare the capsule properties (mechanical resistance and release of actives). The oil encapsulation using O/W emulsions was easier to perform and did not require the use of emulsion destabilisers. However, capsules produced from W/O emulsions were more resistant to compression and showed the slower release of actives over time. The findings detailed here widened the knowledge of the inverse gelation and gave opportunities to develop new techniques of oil encapsulation.

Controlled release for crop and wood protection: Recent progress toward sustainable and safe nanostructured biocidal systems

We review biocide delivery systems (BDS), which are designed to deter or control harmful organisms that damage agricultural crops, forests and forest products. This is a timely topic, given the growing socio-economical concerns that have motivated major developments in sustainable BDS. Associated designs aim at improving or replacing traditional systems, which often consist of biocides with extreme behavior as far as their solubility in water. This includes those that compromise or pollute soil and water (highly soluble or volatile biocides) or those that present low bioavailability (poorly soluble biocides). Major breakthroughs are sought to mitigate or eliminate consequential environmental and health impacts in agriculture and silviculture. Here, we consider the most important BDS vehicles or carriers, their synthesis, the environmental impact of their constituents and interactions with the active components together with the factors that affect their rates of release such as environmental factors and interaction of BDS with the crops or forest products. We put in perspective the state-of-the-art nanostructured carriers for controlled release, which need to address many of the challenges that exist in the application of BDS.

Nanotechnology in Sustainable Agriculture: Recent Developments, Challenges, and Perspectives

Nanotechnology monitors a leading agricultural controlling process, especially by its miniature dimension. Additionally, many potential benefits such as enhancement of food quality and safety, reduction of agricultural inputs, enrichment of absorbing nanoscale nutrients from the soil, etc. allow the application of nanotechnology to be resonant encumbrance. Agriculture, food, and natural resources are a part of those challenges like sustainability, susceptibility, human health, and healthy life. The ambition of nanomaterials in agriculture is to reduce the amount of spread chemicals, minimize nutrient losses in fertilization and increased yield through pest and nutrient management. Nanotechnology has the prospective to improve the agriculture and food industry with novel nanotools for the controlling of rapid disease diagnostic, enhancing the capacity of plants to absorb nutrients among others. The significant interests of using nanotechnology in agriculture includes specific applications like nanofertilizers and nanopesticides to trail products and nutrients levels to increase the productivity without decontamination of soils, waters, and protection against several insect pest and microbial diseases. Nanotechnology may act as sensors for monitoring soil quality of agricultural field and thus it maintain the health of agricultural plants. This review covers the current challenges of sustainability, food security and climate change that are exploring by the researchers in the area of nanotechnology in the improvement of agriculture.

Prospects for malaria control through manipulation of mosquito larval habitats and olfactory-mediated behavioural responses using plant-derived compounds

Malaria presents an overwhelming public health challenge, particularly in sub-Saharan Africa where vector favourable conditions and poverty prevail, potentiating the disease burden. Behavioural variability of malaria vectors poses a great challenge to existing vector control programmes with insecticide resistance already acquired to nearly all available chemical compounds. Thus, approaches incorporating plant-derived compounds to manipulate semiochemical-mediated behaviours through disruption of mosquito olfactory sensory system have considerably gained interests to interrupt malaria transmission cycle. The combination of push-pull methods and larval control have the potential to reduce malaria vector populations, thus minimising the risk of contracting malaria especially in resource-constrained communities where access to synthetic insecticides is a challenge. In this review, we have compiled information regarding the current status of knowledge on manipulation of larval ecology and chemical-mediated behaviour of adult mosquitoes with plant-derived compounds for controlling mosquito populations. Further, an update on the current advancements in technologies to improve longevity and efficiency of these compounds for field applications has been provided.

Budding trends in integrated pest management using advanced micro- and nano-materials: Challenges and perspectives

One of the most vital supports to sustain human life on the planet earth is the agriculture system that has been constantly challenged in terms of yield. Crop losses due to insect pest attack even after excessive use of chemical pesticides, are major concerns for humanity and environment protection. By the virtue of unique properties possessed by micro and nano-structures, their implementation in Agri-biotechnology is largely anticipated. Hence, traditional pest management strategies are now forestalling the potential of micro and nanotechnology as an effective and viable approach to alleviate problems pertaining to pest control. These technological innovations hold promise to contribute enhanced productivity by providing novel agrochemical agents and delivery systems. Application of these systems engages to achieve: i) control release of agrochemicals, ii) site-targeted delivery of active ingredients to manage specific pests, iii) reduced pesticide use, iv) detection of chemical residues, v) pesticide degradation, vi) nucleic acid delivery and vii) to mitigate post-harvest damage. Applications of micro and nano-technology are still marginal owing to the perception of low economic returns, stringent regulatory issues involving safety assessment and public awareness over their uses. In this review, we highlight the potential application of micro and nano-materials with a major focus on effective pest management strategies including safe handling of pesticides.

Electrospun nanofibres in agriculture and the food industry: a review

The interesting characteristics of electrospun nanofibres, such as high surface-to-volume ratio, nanoporosity, and high safety, make them suitable candidates for use in a variety of applications. In the recent decade, electrospun nanofibres have been applied to different potential fields such as filtration, wound dressing, drug delivery, etc. and a significant number of review papers have been published in these fields. However, the use of electrospun nanofibres in agriculture is comparatively novel and is still in its infancy. In this paper, the specific applications of electrospun nanofibres in agriculture and food science, including plant protection using pheromone-loaded nanofibres, plant protection using encapsulation of biocontrol agents, preparation of protective clothes for farm workers, encapsulation of agrochemical materials, deoxyribonucleic acid extraction in agricultural research studies, pre-concentration and measurement of pesticides in crops and environmental samples, preparation of nanobiosensors for pesticide detection, encapsulation of food materials, fabrication of food packaging materials, and filtration of beverage products are reviewed and discussed. This paper may help researchers develop the use of electrospun nanofibres in agriculture and food science to address some serious problems such as the intensive use of pesticides. © 2016 Society of Chemical Industry.

Comparative cytotoxic and genotoxic effects of permethrin and its nanometric form on human erythrocytes and lymphocytes in vitro

The research on the novel pesticides such as nanopesticides has become inevitable to control the mosquito population. Nanopermethrin (NP), one of such kind was formulated in pesticide loaded oil-in-water (o/w) microemulsion by rapid evaporation. Even though NP possess improved efficacy against the target pests, the toxicological investigation on the human or mammalian system remains unexplored. So, the present study focused on a comparative investigation of the cytotoxic and genotoxic effects of NP in vitro and its commercial parental bulk form of permethrin (BP) on human peripheral erythrocyte/lymphocyte by erythrocyte morphology analysis, cell viability assay, and cytokinesis-block micronucleus (CBMN) assay. The NP and BP concentrations (10, 25, 50 and 100 μg/ml) interacted with human blood cells, and the morphological changes were observed using a phase contrast microscope. The drastic increase of echinocyte was observed at 24, 48 and 72 h treatment as compared with the control. The cell viability studies have shown the significant decrease with increase in NP and BP concentration. CBMN study showed a series correlation in the number of micronuclei, bridge, bud, trinucleated and tetranucleated when interacted with different levels of NP and BP, as comparative to control *p < 0.05, **p < 0.001, ***p < 0.0001.

Comparative cytotoxicity and genotoxicity of cobalt (II, III) oxide, iron (III) oxide, silicon dioxide, and aluminum oxide nanoparticles on human lymphocytes in vitro

Despite the extensive use of nanoparticles (NPs) in various fields, adequate knowledge of human health risk and potential toxicity is still lacking. The human lymphocytes play a major role in the immune system, and it can alter the antioxidant level when exposed to NPs. Identification of the hazardous NPs was done using in vitro toxicity tests and this study mainly focuses on the comparative in vitro cytotoxicity and genotoxicity of four different NPs including cobalt (II, III) oxide (Co3O4), iron (III) oxide (Fe2O3), silicon dioxide (SiO2), and aluminum oxide (Al2O3) on human lymphocytes. The Co3O4 NPs showed decrease in cellular viability and increase in cell membrane damage followed by Fe2O3, SiO2, and Al2O3 NPs in a dose-dependent manner after 24 h of exposure to human lymphocytes. The oxidative stress was evidenced in human lymphocytes by the induction of reactive oxygen species, lipid peroxidation, and depletion of catalase, reduced glutathione, and superoxide dismutase. The Al2O3 NPs showed the least DNA damage when compared with all the other NPs. Chromosomal aberration was observed at 100 µg/ml when exposed to Co3O4 NPs and Fe2O3 NPs. The alteration in the level of antioxidant caused DNA damage and chromosomal aberration in human lymphocytes.

Antibacterial activity of neem nanoemulsion and its toxicity assessment on human lymphocytes in vitro

Neem (Azadirachta indica) is recognized as a medicinal plant well known for its antibacterial, antimalarial, antiviral, and antifungal properties. Neem nanoemulsion (NE) (O/W) is formulated using neem oil, Tween 20, and water by high-energy ultrasonication. The formulated neem NE showed antibacterial activity against the bacterial pathogen Vibrio vulnificus by disrupting the integrity of the bacterial cell membrane. Despite the use of neem NE in various biomedical applications, the toxicity studies on human cells are still lacking. The neem NE showed a decrease in cellular viability in human lymphocytes after 24 hours of exposure. The neem NE at lower concentration (0.7-1 mg/mL) is found to be nontoxic while it is toxic at higher concentrations (1.2-2 mg/mL). The oxidative stress induced by the neem NE is evidenced by the depletion of catalase, SOD, and GSH levels in human lymphocytes. Neem NE showed a significant increase in DNA damage when compared to control in human lymphocytes (P<0.05). The NE is an effective antibacterial agent against the bacterial pathogen V. vulnificus, and it was found to be nontoxic at lower concentrations to human lymphocytes.