Encapsulation and controlled release of hydrophilic pesticide in shell cross-linked nanocapsules containing aqueous core

Protein-polymer bioconjugation, immobilization, and encapsulation: a comparative review towards applicability, functionality, activity, and stability

Polymer-based biomaterials have received a lot of attention due to their biomedical, agricultural, and industrial potential. Soluble protein-polymer bioconjugates, immobilized proteins, and encapsulated proteins have been shown to tune enzymatic activity, improved pharmacokinetic ability, increased chemical and thermal stability, stimuli responsiveness, and introduced protein recovery. Controlled polymerization techniques, increased protein-polymer attachment techniques, improved polymer surface grafting techniques, controlled polymersome self-assembly, and sophisticated characterization methods have been utilized for the development of well-defined polymer-based biomaterials. In this review we aim to provide a brief account of the field, compare these methods for engineering biomaterials, provide future directions for the field, and highlight impacts of these forms of bioconjugation.

Gas-Phase Functionalization of Phytoglycogen Nanoparticles and the Role of Reagent Structure in the Formation of Self-Limiting Hydrophobic Shells

A suite of acyl chloride structural isomers (C6H11OCl) was used to effect gas-phase esterification of starch-based phytoglycogen nanoparticles (PhG NPs). The surface degree of substitution (DS) was quantified using X-ray photoelectron spectroscopy, while the overall DS was quantified using 1H NMR spectroscopy. Gas-phase modification initiates at the NP surface, with the extent of surface and overall esterification determined by both the reaction time and the steric footprint of the acyl chloride reagent. The less sterically hindered acyl chlorides diffuse fully into the NP interior, while the branched isomers are restricted to the near-surface region and form self-limiting hydrophobic shells, with shell thicknesses decreasing with increasing steric footprint. These differences in substitution were also reflected in the solubility of the NPs, with water solubility systematically decreasing with increasing DS. The ability to separately control both the surface and overall degree of functionalization and thereby form thin hydrophobic shells has significant implications for the development of polysaccharide-based biopolymers as nanocarrier delivery systems.

Unleashing the potential of nanoparticles on seed treatment and enhancement for sustainable farming

The foremost challenge in farming is the storage of seeds after harvest and maintaining seed quality during storage. In agriculture, studies showed positive impacts of nanotechnology on plant development, seed storage, endurance under various types of stress, detection of seed damages, and seed quality. Seed's response varies with different types of nanoparticles depending on its physical and biochemical properties and plant species. Herein, we aim to cover the impact of nanoparticles on seed coating, dormancy, germination, seedling, nutrition, plant growth, stress conditions protection, and storage. Although the seed treatment by nanopriming has been shown to improve seed germination, seedling development, stress tolerance, and seedling growth, their full potential was not realized at the field level. Sustainable nano-agrochemicals and technology could provide good seed quality with less environmental toxicity. The present review critically discusses eco-friendly strategies that can be employed for the nanomaterial seed treatment and seed enhancement process to increase seedling vigor under different conditions. Also, an integrated approach involving four innovative concepts, namely green co-priming, nano-recycling of agricultural wastes, nano-pairing, and customized nanocontainer storage, has been proposed to acclimatize nanotechnology in farming.

Research Progress of a Pesticide Polymer-Controlled Release System Based on Polysaccharides

In recent years, with the development of the nanomaterials discipline, many new pesticide drug-carrying systems-such as pesticide nano-metal particles, nano-metal oxides, and other drug-carrying materials-had been developed and applied to pesticide formulations. Although these new drug-loading systems are relatively friendly to the environment, the direct exposure of many metal nanoparticles to the environment will inevitably lead to potential effects. In response to these problems, organic nanomaterials have been rapidly developed due to their high-quality biodegradation and biocompatibility. Most of these organic nanomaterials were mainly polysaccharide materials, such as chitosan, carboxymethyl chitosan, sodium alginate, β-cyclodextrin, cellulose, starch, guar gum, etc. Some of these materials could be used to carry inorganic materials to develop a temperature- or pH-sensitive pesticide drug delivery system. Herein, the pesticide drug-carrying system developed based on polysaccharide materials, such as chitosan, was referred to as the pesticide polymer drug-carrying system based on polysaccharide materials. This kind of drug-loading system could be used to protect the pesticide molecules from harsh environments, such as pH, light, temperature, etc., and was used to develop the function of a sustained release, targeted release of pesticides in the intestine of insects, and achieve the goal of precise application, reduction, and efficiency of pesticides. In this review, the recent progress in the field of polysaccharide-based polymer drug delivery systems for pesticides has been discussed, and suggestions for future development were proposed based on the current situation.

Nanopesticides in comparison with agrochemicals: Outlook and future prospects for sustainable agriculture

Agrochemicals are products of advanced technologies that use inorganic pesticides and fertilizers. Widespread use of these compounds has adverse environmental effects, leading to acute and chronic exposure. Globally, scientists are adopting numerous green technologies to ensure a healthy and safe food supply and a livelihood for everyone. Nanotechnologies significantly impact all aspects of human activity, including agriculture, even if synthesizing certain nanomaterials is not environmentally friendly. Numerous nanomaterials may therefore make it easier to create natural insecticides, which are more effective and environmentally friendly. Nanoformulations can improve efficacy, reduce effective doses, and extend shelf life, while controlled-release products can improve the delivery of pesticides. Nanotechnology platforms enhance the bioavailability of conventional pesticides by changing kinetics, mechanisms, and pathways. This allows them to bypass biological and other undesirable resistance mechanisms, increasing their efficacy. The development of nanomaterials is expected to lead to a new generation of pesticides that are more effective and safer for life, humans, and the environment. This article aims to express at how nanopesticides are being used in crop protection now and in the future. This review aims to shed some light on the various impacts of agrochemicals, their benefits, and the function of nanopesticide formulations in agriculture.

Recent Advances in Nano-Enabled Seed Treatment Strategies for Sustainable Agriculture: Challenges, Risk Assessment, and Future Perspectives

Agro seeds are vulnerable to environmental stressors, adversely affecting seed vigor, crop growth, and crop productivity. Different agrochemical-based seed treatments enhance seed germination, but they can also cause damage to the environment; therefore, sustainable technologies such as nano-based agrochemicals are urgently needed. Nanoagrochemicals can reduce the dose-dependent toxicity of seed treatment, thereby improving seed viability and ensuring the controlled release of nanoagrochemical active ingredients However, the applications of nanoagrochemicals to plants in the field raise concerns about nanomaterial safety, exposure levels, and toxicological implications to the environment and human health. In the present comprehensive review, the development, scope, challenges, and risk assessments of nanoagrochemicals on seed treatment are discussed. Moreover, the implementation obstacles for nanoagrochemicals use in seed treatments, their commercialization potential, and the need for policy regulations to assess possible risks are also discussed. Based on our knowledge, this is the first time that we have presented legendary literature to readers in order to help them gain a deeper understanding of upcoming nanotechnologies that may enable the development of future generation seed treatment agrochemical formulations, their scope, and potential risks associated with seed treatment.

Advances in Biopolymeric Nanopesticides: A New Eco-Friendly/Eco-Protective Perspective in Precision Agriculture

Pesticides are essential to contemporary agriculture and are required to safeguard plants from hazardous pests, diseases, and weeds. In addition to harming the environment, overusing these pesticides causes pests to become resistant over time. Alternative methods and agrochemicals are therefore required to combat resistance. A potential solution to pesticide resistance and other issues may be found in nanotechnology. Due to their small size, high surface-area-to-volume ratio, and ability to offer novel crop protection techniques, nanoformulations, primarily biopolymer-based ones, can address specific agricultural concerns. Several biopolymers can be employed to load pesticides, including starch, cellulose, chitosan, pectin, agar, and alginate. Other biopolymeric nanomaterials can load pesticides for targeted delivery, including gums, carrageenan, galactomannans, and tamarind seed polysaccharide (TSP). Aside from presenting other benefits, such as reduced toxicity, increased stability/shelf life, and improved pesticide solubility, biopolymeric systems are also cost-effective; readily available; biocompatible; biodegradable; and biosafe (i.e., releasing associated active compounds gradually, without endangering the environment) and have a low carbon footprint. Additionally, biopolymeric nanoformulations support plant growth while improving soil aeration and microbial activity, which may favor the environment. The present review provides a thorough analysis of the toxicity and release behavior of biopolymeric nanopesticides for targeted delivery in precision crop protection.

Repurposing of Marine Raw Materials in the Formulation of Innovative Plant Protection Products

Over the years, the growth of the world population has caused a huge agricultural production to support the population's needs. Since plant protection products are essential to preserve agricultural crops and to optimize vital plant processes, it is crucial to use more sustainable, biodegradable, and biocompatible raw materials, without harming the environment and human health. Although the development of new plant protection products is a costly process, the environmental benefits should be considered. In this context, marine raw materials obtained as byproducts of fishing industries, possessing a wide variety of physicochemical and biological properties, can serve as a promising source of such materials. They have a high potential for developing alternative and safe formulations for agricultural applications, not only as biocompatible excipients but also as effective and selective, or even both. It is also possible to promote a synergistic effect between an active substance and the biological activity of the marine polymer used in the formulation, enabling plant protection products with lower concentrations of the active substances. Thus, this review addresses the repurposing of marine raw materials for the development of innovative plant protection products, focusing on micro- and nanoparticulate formulations, to protect the environment through more ecological and sustainable strategies.

Modelling and assessment of plasticizer migration and structure changes in hydrophobic starch-based films

The structures of starch and starch-based materials determine additives migration from material matrix. Propionylated starch derived from waxy, normal, G50 and G80 starch were selected as the matrix, the amylose effect on plasticizer (triacetin) migration as well as structural changes in hydrophobic starch-based films were discussed. The constant (k₁) of first-order rate and initial release rate (V₀) of triacetin migration were consistent with the increment of amylose content. Meanwhile, diffusion model disclosed that Fick's second law was apposite to characterize the short-term migration of triacetin, and larger diffusion coefficient (D) values of short- and long-term migration were also found in films with higher amylose content, indicating that amylose-formed structures were in favor of triacetin migration. In comparison of propionylated amylopectin, Van der Waals's interactions between propionylated amylose and triacetin were easier to be weakened with the migration of triacetin, which promoted the decrease of wavenumber of C-O-C, and enlarged the inter-planner spacing of crystalline structures, promoting the formation of amorphous structures and wrinkles and embossments in films with higher amylose content. This work confirmed that regulating the structures of starch were effective to control the migration behavior of additives from starch-based films.

Smart nanomaterial and nanocomposite with advanced agrochemical activities

Conventional agriculture solely depends upon highly chemical compounds that have negatively ill-affected the health of every living being and the entire ecosystem. Thus, the smart delivery of desired components in a sustainable manner to crop plants is the primary need to maintain soil health in the upcoming years. The premature loss of growth-promoting ingredients and their extended degradation in the soil increases the demand for reliable novel techniques. In this regard, nanotechnology has offered to revolutionize the agrotechnological area that has the imminent potential over conventional agriculture and helps to reform resilient cropping systems withholding prominent food security for the ever-growing world population. Further, in-depth investigation on plant-nanoparticles interactions creates new avenues toward crop improvement via enhanced crop yield, disease resistance, and efficient nutrient utilization. The incorporation of nanomaterial with smart agrochemical activities and establishing a new framework relevant to enhance efficacy ultimately help to address the social acceptance, potential hazards, and management issues in the future. Here, we highlight the role of nanomaterial or nanocomposite as a sustainable as well stable alternative in crop protection and production. Additionally, the information on the controlled released system, role in interaction with soil and microbiome, the promising role of nanocomposite as nanopesticide, nanoherbicide, nanofertilizer, and their limitations in agrochemical activities are discussed in the present review.

Fate of Biodegradable Engineered Nanoparticles Used in Veterinary Medicine as Delivery Systems from a One Health Perspective

The field of veterinary medicine needs new solutions to address the current challenges of antibiotic resistance and the need for increased animal production. In response, a multitude of delivery systems have been developed in the last 20 years in the form of engineered nanoparticles (ENPs), a subclass of which are polymeric, biodegradable ENPs, that are biocompatible and biodegradable (pbENPs). These platforms have been developed to deliver cargo, such as antibiotics, vaccines, and hormones, and in general, have been shown to be beneficial in many regards, particularly when comparing the efficacy of the delivered drugs to that of the conventional drug applications. However, the fate of pbENPs developed for veterinary applications is poorly understood. pbENPs undergo biotransformation as they are transferred from one ecosystem to another, and these transformations greatly affect their impact on health and the environment. This review addresses nanoparticle fate and impact on animals, the environment, and humans from a One Health perspective.

Electrostatic wrapping of eupatorium-based botanical herbicide with chitosan derivatives for controlled release

To avoid the negative effects of chemical herbicides and prepare herbicide with long-term efficacy, the active ingredients of eupatorium adenophorum spreng (AIEAS, negatively charged) were used as a botanical herbicide, and based on electrostatic attraction, the self-assembled hydroxyl isopropyl chitosan (HPCTS, positively charged) and carboxymethyl chitosan (CMC, with good water solubility) were successfully employed as degradable and water-soluble carrier for AIEAS to realize its controlled release. The release of AIEAS from the chitosan carrier in water could be divided into two stages. In the first stage, a fast release of AIEAS was detected and the total amount of the released AIEAS reached 41.5 %, while the release rate effectively slowed down in the second stage, indicating that good balance between fast control of weeds and long-term efficacy was achieved through this controlled delivery system. The release kinetics of AIEAS during the whole release process showed good fit to the Ritger-Peppas model with Fickian diffusion as the dominant release mechanism. Moreover, it found that the released AIEAS from chitosan carrier showed fine herbicidal effect on barnyard grass.

Effects of microencapsulated abamectin on the mechanical, cross-linking, and release properties of PBS

Herein, nanocomposite microencapsulated abamectin (A-G-G) have been prepared by composite coacervation method with gelatin and gum arabic as the wall materials and abamectin (A-W) as core material. The formation mechanism of A-G-G was determined by fourier-transform infrared spectroscopy, scanning electron microscopy, and other characterization methods. Then, polybutylene succinate (PBS)/A-G-G composite films with different contents of A-G-G microcapsules were prepared. The effects of adding A-G-G microcapsules on the mechanical and sustained-release properties of the composite films were studied. Results show that there is a strong interaction between the CO groups in PBS and free OH of the A-G-G microcapsules. With an increase in the A-G-G microcapsule content, the elongation at the break of composite films increases significantly. When the A-G-G content is 15 %, the elongation at break of the composite films reaches 178.6 ± 6.26 %. The maximum water absorption is 329 ± 5.84 %. Overall, the PBS/A-G-G composite films exhibit good slow-release performance.

Chitosan-Based Agronanochemicals as a Sustainable Alternative in Crop Protection

The rise in the World's food demand in line with the increase of the global population has resulted in calls for more research on the production of sustainable food and sustainable agriculture. A natural biopolymer, chitosan, coupled with nanotechnology could offer a sustainable alternative to the use of conventional agrochemicals towards a safer agriculture industry. Here, we review the potential of chitosan-based agronanochemicals as a sustainable alternative in crop protection against pests, diseases as well as plant growth promoters. Such effort offers better alternatives: (1) the existing agricultural active ingredients can be encapsulated into chitosan nanocarriers for the formation of potent biocides against plant pathogens and pests; (2) the controlled release properties and high bioavailability of the nanoformulations help in minimizing the wastage and leaching of the agrochemicals' active ingredients; (3) the small size, in the nanometer regime, enhances the penetration on the plant cell wall and cuticle, which in turn increases the argochemical uptake; (4) the encapsulation of agrochemicals in chitosan nanocarriers shields the toxic effect of the free agrochemicals on the plant, cells and DNA, thus, minimizing the negative impacts of agrochemical active ingredients on human health and environmental wellness. In addition, this article also briefly reviews the mechanism of action of chitosan against pathogens and the elicitations of plant immunity and defense response activities of chitosan-treated plants.

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

Inefficient usage and overdosage of conventional pesticide formulations has resulted in large economic losses and environmental pollution due to their poor water solubility and weak adhesion to foliage. In order to develop a green and efficient pesticide formulation, a kind of alkyd resin (AR) based on vegetable oil was first synthesized and used to fabricate the lambda-cyhalothrin/AR (LC/AR) nanoemulsion via in situ phase inverse emulsification, and its properties were then investigated. Results showed that the particle size of the LC/AR nanoemulsion was 50-150 nm with maximum LC loading capacity of as much as 40.9 wt %, high encapsulation efficiency >90%, and great stability in multiple environments. The LC/AR nanoemulsion exhibited better controlled release characteristics compared with LC commercial formulations, and a stronger adhesion on the foliage of the resulted nanoemulsion was also observed, which was attributed to low surface tension and strong interactions with foliar surfaces.

Neem oil-loaded cross-linked biodegradable polymeric capsules: Its larvicidal activity against Culex quinquefasciatuss larvae

Background:

Pesticide delivery system has been formulated in the form of emulsifiable concentrates, water solutions, aerosols, or spray formulations. However, such formulations showed health hazards. Encapsulation technique is the more suitable method to reduce health hazard and to deliver and release the pesticides. Natural biopolymers have been widely studied for encapsulation of pesticide compounds, as they are biodegradable, biocompatible, and low toxic to mammalian. Neem oil has been reported for controlling of the mosquitoes and more eco-friendly insecticide than synthetic insecticides. The present study was designed to prepare a cross-linked polymeric network capsules loaded with neem oil as effective controlled release formulation against Culex quinquefasciatus larvae.

Materials and Methods:

Neem oil-loaded chitosan/alginate/gelatin capsules were prepared by cross-linking method. Neem oil-loaded capsules were characterized with respect to their capsule size, scanning electron microscopy (SEM) analysis, and swelling property. In vitro larvicidal activity of neem oil-loaded polymeric capsules was studied against C. quinquefasciatus larvae.

Results:

The cross-linking method produced spherical shape of neem oil-loaded capsules. Ultraviolet spectroscopy analysis indicated that 10% of neem oil was loaded with capsule. A swelling study indicated that swelling of the loaded capsules tends to be more stable. SEM analysis showed that loading of the neem oil with the capsules fills all pores and capsules were found with good compatibility between chitosan, alginate, and gelatin due to the uniform shape of the capsule. Formulated neem oil-loaded capsules showed potential larvicidal activity (100% of mortality) against C. quinquefasciatus larvae in an in vitro model.

Conclusion:

Formulated neem oil-loaded capsules showed a simple method of preparation and eco-friendly. These polymeric capsule containing neem oil exhibited potential larvicidal activity against C. quinquefasciatus larvae.

Local applications but global implications: Can pesticides drive microorganisms to develop antimicrobial resistance?

Pesticides are an important agricultural input, and the introduction of new active ingredients with increased efficiencies drives their higher production and consumption worldwide. Inappropriate application and storage of these chemicals often contaminate plant tissues, air, water, or soil environments. The presence of pesticides can lead to developing tolerance, resistance or persistence and even the capabilities to degrade them by the microbiomes of theses environments. The pesticide-degrading microorganisms gain and employ several mechanisms for attraction (chemotaxis), membrane transport systems, efflux pumps, enzymes and genetical make-up with plasmid and chromosome encoded catabolic genes for degradation. Even the evolution and the mechanisms of inheritance for pesticide-degradation as a functional trait in several microorganisms are beginning to be understood. Because of the commonalities in the microbial responses of sensing and uptake, and adaptation due to the selection pressures of pesticides and antimicrobial substances including antibiotics, the pesticide-degraders have higher chances of possessing antimicrobial resistance as a surplus functional trait. This review critically examines the probabilities of pesticide contamination of soil and foliage, the knowledge gaps in the regulation and storage of pesticide chemicals, and the human implications of pesticide-degrading microorganisms with antimicrobial resistance in the global strategy of 'One Health'.

Plant-Derived Substances Used Against Beetles-Pests of Stored Crops and Food-and Their Mode of Action: A Review

Plants are sources of numerous active substances that are used to protect crops. Currently, due to the limitations of using synthetic insecticides, plant products have attracted increasing attention as possible pesticides. In this review, we discuss some of the most interesting plant products (for example, Solanaceae, or Asteraceae extracts, Artemisia absinthium or Citrus spp. essential oils, and single compounds like α-chaconine, or α-solanine) that exhibit insecticidal activity against beetles that are pests of stored food products. Next, we describe and discuss the mode of action of these products, including lethal and sublethal effects, such as antifeedant or neurotoxic activity, ultrastructural malformation, and effects on prooxidant/antioxidant balance. Furthermore, the methods of application of plant-derived substances in food storage areas are presented.

Development of a Chlorantraniliprole Microcapsule Formulation with a High Loading Content and Controlled-Release Property

Microcapsule formulations have been widely developed and used in agriculture to improve pesticide utilization and reduce environmental pollution. However, commercial formulations of chlorantraniliprole (CAP) are only traditional formulations due to poor solubility of CAP in organic solvents. Here, adopting a solid in oil in water (S/O/W) double-emulsion method combined with premix membrane emulsion, we successfully constructed CAP microcapsule formulations with a high loading content. The microcapsule formulations with good light and thermal stability showed a significantly sustained release for a long period, which could be optimally regulated by tuning the surface porosity and size of the porous microcapsules. Bioassay studies showed that control efficacy of the porous microcapsule formulations against Plutella xylostella was superior to that of the commercial formulation. These results demonstrated that such a porous microcapsule delivery system should have great potential for further exploration as a commercial CAP formulation.

Construction and Characterization of a Novel Sustained-Release Delivery System for Hydrophobic Pesticides Using Biodegradable Polydopamine-Based Microcapsules

Microcapsule formulations have been highly desirable and widely developed for effective utilization of pesticides and environmental pollution reduction. However, commercial and traditional microcapsule formulations of λ-cyhalothrin (LC) were prepared by complicated synthesis procedures and thereby specific organic solvents were needed. In this work, LC was encapsulated into versatile, robust, and biodegradable polydopamine (PDA) microcapsules by self-polymerization of dopamine. LC-loaded PDA microcapsules were characterized by transmission electron microscopy (TEM), small-angle X-ray scattering (SAXS), and thermogravimetric analysis measurements (TGA). LC-loaded PDA microcapsules have uniform morphology with nanoscale, decent LC loading content (>50.0% w/w), and good physicochemical stability and sustained release properties. The bioassay against housefly ( Musca domestica) showed that the bioactivity and long-term efficiency of LC-loaded PDA microcapsules was superior to that of the commercial formulation. All of these results demonstrated that LC-loaded PDA microcapsules could be applied as a commercial LC microcapsule formulation with fewer environmental side effects and higher effective delivery.

Fabrication and characterization of β-cypermethrin-loaded PLA microcapsules prepared by emulsion-solvent evaporation: loading and release properties

Microcapsulses can be designed to effectively encapsulate, protect, and control the release of pesticides. In this study, emulsion-solvent evaporation method was used to fabricate microcapsules using dichloromethane as the solvent, polylactic acid (PLA) as the carrier materials, poly(vinyl alcohol) as the emulsifier, and β-cypermethrin as the entrapped pesticide. The effects of process parameters on the microcapsules characteristics (size, loading content, and encapsulation efficiency) were investigated. Also, the release behavior of the β-cypermethrin was measured experimentally and modeled mathematically. Kinetic analysis indicated that release mechanism of β-cypermethrin was compatible to Fickian diffusion. By optimizing the process parameters, β-cypermethrin-loaded microcapsules were successfully produced with spherical shape, smooth surface, high encapsulation efficiency (> 80%), and a range of pesticide contents. These parameters could be adjusted to achieve delivery systems with desirable release profiles. The results are beneficial to develop delivery systems for rational and effective usage of pesticides.

One-Step Generation of Salt-Responsive Polyelectrolyte Microcapsules via Surfactant-Organized Nanoscale Interfacial Complexation in Emulsions (SO NICE)

Polyelectrolyte microcapsules are versatile compartments for encapsulation, protection, and controlled/triggered release of active agents. Conventional methods of polyelectrolyte microcapsule preparation require multiple steps or do not allow for efficient encapsulation of active agents in the lumen of the microcapsule. In this work, we present the fabrication of hollow polyelectrolyte microcapsules with a salt-responsive property based on surfactant organized nanoscale interfacial complexation in emulsions (SO NICE). In SO NICE, polyelectrolyte microcapsules are templated by water-in-oil-in-water (W/O/W) double emulsions. One polyelectrolyte is dissolved in the inner water droplet of the W/O/W double emulsions, whereas the second polyelectrolyte is dissolved in the organic phase by hydrophobic ion paring with an oppositely charged hydrophobic surfactant. Interfacial complexation of the two polyelectrolytes generates a few hundred-nanometer thick film at the inner water-oil interface of the W/O/W double emulsions. SO NICE microcapsules can be triggered to release their cargo by increasing the ionic strength of the solution, which is a hallmark of polyelectrolyte-based microcapsules. By enabling dissolution and interfacial complexation of polyelectrolytes in organic solvents, SO NICE widens the pallet of polymers that can be used to generate functional polyelectrolyte microcapsules with high encapsulation efficiency for applications in encapsulation and controlled/triggered release.

Electrolyte and pH-sensitive amphiphilic alginate: synthesis, self-assembly and controlled release of acetamiprid

In this study, a pH-responsive amphiphilic alginate (Ugi-Alg) was synthesized via Ugi reaction without using a catalyst. The structure of Ugi-Alg was confirmed by FT-IR and ¹H NMR spectroscopy. Amphiphilic alginate can form micelles in an aqueous medium due to it's amphiphilic nature.. The impacts of Na⁺ concentration and pH on the micelle size were characterized by dynamic light scattering (DLS) and transmission electron microscopy (TEM). The dynamic light scattering observations showed that micelle size increases with the decrease in Na⁺ concentration in aqueous solution. However, the micelle size decreases first and then increases as the pH value decreases from 5.3 to 2.0. Transmission electron microscopy confirmed that the mean size of micelles is 30–200 nm. In addition, a model hydrophobic pesticide (acetamiprid) was loaded in the micelles. The encapsulation efficiency and release behavior of micelles were studied, which could be controlled by Na⁺ concentration and pH. The results indicated that encapsulation efficiency of acetamiprid increases from 55% to 96% due to the increase in Na⁺ concentration from 0.01 M to 0.3 M. Moreover, with the decrease in pH from 5.3 to 2.0, encapsulation efficiency increases from 55% to 80%. Furthermore, the data of acetamiprid release kinetics could be well-fitted by the Weibull model.

Schematic of Ugi-Alg aggregation in aqueous solution of different NaCl concentrations and pH values.

A two-step synthesis for preparing metal microcapsules with a biodegradable polymer substrate

Novel method of producing metal microcapsules, using nanoparticles as the stabiliser, allows better control of nanoparticle distribution thus optimisation of metal shells.

Understanding the Mechanisms of Gold Shell Growth onto Polymer Microcapsules to Control Shell Thickness

Polymer microcapsules have been used commercially for decades, however they have an inherent flaw which renders them impractical as a carrier of small, volatile molecules. The porous nature of the polymer shell allows for diffusion of the encapsulated molecules into the bulk. The use of metal shells is an innovative way to prevent undesired loss of small molecules from the core of microcapsules, however it is important, particularly when using expensive metals to ensure that the resulting shell is as thin as possible. Here we investigate the fundamental mechanisms controlling the gold shell thickness when a fragrance oil is encapsulated in a poly(methyl methacrylate) shell. We consider the distribution of the nanoparticles on the capsule surface, and from quantification of the adsorbed nanoparticle (NP) density and resulting shell thickness, we propose mechanisms to describe the gold shell growth for systems with high and low NP surface coverage. We suggest from our observations that the gold grows to fill in the gaps between NPs. At low NP concentrations, thicker metal shells form. We postulate that this is due to the low NP density on the surface, forcing the gold clusters to grow larger before they meet the adjacent ones. Thus, to grow the thinnest possible shells a densely packed monolayer of platinum nanoparticles is required on the capsule surface.

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.

Platinum covalent shell cross-linked micelles designed to deliver doxorubicin for synergistic combination cancer therapy

The preparation of polymer therapeutics capable of controlled release of multiple chemotherapeutic drugs has remained a tough problem in synergistic combination cancer therapy. Herein, a novel dual-drug co-delivery system carrying doxorubicin (DOX) and platinum(IV) (Pt[IV]) was developed. An amphiphilic diblock copolymer, PCL-b-P(OEGMA-co-AzPMA), was synthesized and used as a nanoscale drug carrier in which DOX and Pt(IV) could be packaged together. The copolymers were shell cross-linked by Pt(IV) prodrug via a click reaction. Studies on the in vitro drug release and cellular uptake of the dual-drug co-delivery system showed that the micelles were effectively taken up by the cells and simultaneously released drugs in the cells. Futhermore, the co-delivery polymer nanoparticles caused much higher cell death in HeLa and A357 tumor cells than either the free drugs or single-drug-loaded micelles at the same dosage, exhibiting a synergistic combination of DOX and Pt(IV). The results obtained with the shell cross-linked micelles based on an anticancer drug used as a cross-linking linkage suggested a promising application of the micelles for multidrug delivery in combination cancer therapy.

Preparation and properties of lambda-cyhalothrin/polyurethane drug-loaded nanoemulsions

A new lambda-cyhalothrin/castor oil-based polyurethane formulation with controlled-release behavior and good foliage adhesion properties is prepared.

Construction of a controlled-release delivery system for pesticides using biodegradable PLA-based microcapsules

Conventional pesticides usually need to be used in more than recommended dosages due to their loss and degradation, which results in a large waste of resources and serious environmental pollution. Encapsulation of pesticides in biodegradable carriers is a feasible approach to develop environment-friendly and efficient controlled-release delivery system. In this work, we fabricated three kinds of polylactic acid (PLA) carriers including microspheres, microcapsules, and porous microcapsules for controlled delivery of Lambda-Cyhalothrin (LC) via premix membrane emulsification (PME). The microcapsule delivery system had better water dispersion than the other two systems. Various microcapsules with a high LC contents as much as 40% and tunable sizes from 0.68 to 4.6μm were constructed by manipulating the process parameters. Compared with LC technical and commercial microcapsule formulation, the microcapsule systems showed a significantly sustained release of LC for a longer period. The LC release triggered by LC diffusion and matrix degradation could be optimally regulated by tuning LC contents and particle sizes of the microcapsules. This multi-regulated release capability is of great significance to achieve the precisely controlled release of pesticides. A preliminary bioassay against plutella xylostella revealed that 0.68μm LC-loaded microcapsules with good UV and thermal stability exhibited an activity similar to a commercial microcapsule formulation. These results demonstrated such an aqueous microcapsule delivery system had a great potential to be further explored for developing an effective and environmentally friendly pesticide-release formulation.