Coacervate-Enhanced Deposition of Sprayed Pesticide on Hydrophobic/Superhydrophobic Abaxial Leaf Surfaces

Tailoring Peptide Coacervates for Advanced Biotechnological Applications: Enhancing Control, Encapsulation, and Antioxidant Properties

The increasing interest in protein and peptide coacervates is accompanied by the development of various applications, from drug delivery to biosensor preparation. However, the impact of peptide end groups and charges on coacervation remains unclear. For this purpose, we designed four peptide derivatives with varying end groups and net charges. These inherently fluorescent peptides readily formed coacervates in solution or during evaporation. The ability to control the coacervation process, the coacervate's appearance, and the encapsulation capabilities were thoroughly investigated. The coacervates displayed significant antioxidant properties, protecting the encapsulated material. Additionally, control of the deposition of coacervates on surfaces was achieved. These abilities highlight the potential of these coacervates in biotechnological applications, including biosensor development and the delivery of compounds such as drugs and dietary supplements. Exploiting the dynamic characteristics of coacervates with the unique properties of these peptides underscores their practical advantages.

Stepwise Self-Assembly of Multisegment Mesoporous Silica Nanobamboos for Enhanced Thermal Insulation

Imitating the multinodal structures of plants and arthropods, precisely engineered multisegment nanostructures demonstrate enhanced synergistic properties and exceptional functionalities that surpass those of individual components. Utilizing micelle assemblies for constructing segments allows for precise structural control but requires management of interactions and assembly from molecular to mesoscopic levels, posing a significant challenge. In this paper, we present a stepwise self-assembly strategy to fabricate multisegment mesoporous silica (mSiO2) nanobamboos. The nanobamboos are characterized by 16-25 shuttle-shaped mesoporous segments connected end-to-end in line, forming the main chains with an overall length of approximately 0.7-1.0 μm. Each individual segment is composed of 10-13 parallel layers, with an average layer thickness of ∼2.5 nm. The formation of this multisegment mesoporous nanobamboos, as proven by in situ testing, is initiated by the formation of shuttle-shaped segments from small bilayer micelle units, which then further assemble to form the nanobamboo. This stepwise self-assembly can be regulated from a kinetic perspective, thereby obtaining multisegment mesoporous nanostructures with varying lengths and branched morphologies. Due to multiple segments along with multilayer mesostructures, the nanobamboos can significantly restrict gas flow, resulting in a very low thermal conductivity (∼41.67 mW·m-1·K-1). By blending the multisegment mSiO2 nanobamboos with cellulose nanofibers, mechanically stable, lightweight, and porous aerogels with an ultralow thermal conductivity (∼19.85 mW·m-1·K-1) can be obtained, verifying their potential in thermal insulation devices. The fabrication of this multisegment mesoporous nanobamboos enhances our understanding of micro-to-nanoscale assembling, establishing a foundation for precise control of complex structures.

From De Novo Conceived Small Molecules to Multifunctional Supramolecular Nanoparticles: Dual Biofilm and T3SS Intervention, Enhanced Foliar Affinity, and Effective Rice Disease Control

Conventional antimicrobials typically exhibit suboptimal deposition on rice leaves, resulting in poor efficacy, further impaired by biofilms and Type III Secretion Systems (T3SS). Herein, this study presents a supramolecular strategy to fabricate BtP27@β-CD, a sunflower-like material engineered through host-guest recognition between de novo designed molecule BtP27 and β-cyclodextrin. BtP27@β-CD manifests enhanced foliar affinity and in vivo efficiency, demonstrating superior protective (62.67%) and curative (51.16%) activities against bacterial leaf blight at a low-dose of 200 µg mL-1 compared to commercial thiodiazole-copper (37.78%/38.13%) without compromising safety. This multifunctional material, structurally derived from dufulin, inherit progenitor's systemic and conductive properties, alongside the capacity to activate salicylic acid-mediated plant defense pathways. Moreover, it is endowed with the anticipated abilities to disorganize biofilm barriers, annihilate encased pathogens, and inhibit T3SS. This constitutes the inaugural report of a supramolecular-based biofilm/T3SS dual inhibitor. An expanded investigation into substrate and indication screening identified additional molecules that self-assemble with β-cyclodextrin to form supramolecular materials, exhibiting superior potency against other rice diseases, with protective potency ranging from 63.53% to 73.30% and curative efficacy spanning 42.18% to 60.41% at 200 µg mL-1. In brief, this work establishes a paradigm for designing guest molecules from scratch to construct supramolecular materials with tailored characteristics.

Coacervates Composed of Low-Molecular-Weight Compounds- Molecular Design, Stimuli Responsiveness, Confined Reaction

The discovery of coacervation within living cells through liquid-liquid phase separation has inspired scientists to investigate its fundamental principles and significance. Indeed, coacervates composed of low-molecular-weight compounds based on supramolecular strategy can offer valuable models for biomolecular condensates and useful tools. This mini-review highlights recent findings and advances in coacervates (artificial condensates), primarily composed of low-molecular-weight compounds, with focuses on their molecular design, stimuli responsiveness, and controlled reactions within or leading to the coacervates.

Component Effects on Agricultural Spray

Regulating the spray behavior of liquids is of great importance in various practical applications, especially in improving pesticide utilization efficiency because the spray states are directly related to the spray drift and deposition efficiency. The components of pesticides, including surfactants, polymers, and active ingredients, were found to influence spray behavior significantly. However, because of both the complexity of interactions in sprayed liquids and the technology limit, only a few specific aspects of the formation of droplets have been studied, and a comprehensive and general understanding is still lacking. This brief review summarizes the effects of surfactants, polymers, and active ingredients on spray and highlights the underlying mechanisms related to sheet breakup and droplet formation. Other factors that warrant detailed exploration in the future are proposed, including dilatational viscoelasticity, zeta potential, aggregation, and sheet thickness. Finally, insights into the design of spray additives for agricultural applications are provided.

Fabrication of Multifunctional Three-Component Supramolecular Nano-Biscuits via Two Macrocycles-Involved Self-Assembly for Rice, Citrus and Kiwifruit Protections

Bacterial plant diseases, worsened by biofilm-mediated resistance, are increasingly threatening global food security. Numerous attempts have been made to develop agrochemicals that inhibit biofilms, however, their ineffective foliar deposition and difficulty in removing mature biofilms remain major challenges. Herein, multifunctional three-component supramolecular nano-biscuits (NI6R@CB[7]@β-CD) are successfully engineered via ordered self-assembly between two macrocycles [cucurbit[7]uril (CB[7]), β-cyclodextrin (β-CD)] and (R)-2-naphthol-based bis-imidazolium bromide salt (NI6R). This macrocycles-involved bactericidal material combines many advantages. 1) Alleviate the off-target movement of droplets on hydrophobic blade surfaces. 2) Enhance the biofilm-disrupting ability. At a low-dose of 4.44 µg mL-1, the inhibition rate of biofilm formation reached 78.3%. At 35.5 µg mL-1, the potency to remove mature biofilms reached 77.6%. 3) Efficiently hinder bacterial reproduction, swimming, extracellular polysaccharide production, extracellular enzyme secretion, and virulence to plants. These superior characteristics are undoubtedly transmitted to the in vivo control effect. At 200 µg mL-1, this smart material exhibits superior control efficiencies of 49.6%/65.0%/85.4% against three kinds of bacterial diseases (rice leaf blight, citrus canker, and kiwifruit canker), respectively, surpassing the commercial bactericide-thiodiazole-copper-20%SC (33.6%/41.5%/43.2%) and NI6R (40.3%/51.2%/71.2%). Furthermore, NI6R@CB[7]@β-CD is biosafe to non-target organisms. This study is instructive for constructing multifunctional agrochemicals in sustainable crop protection.

From Natural Product Derivative to Hexagonal Prism Supermolecule: Potent Biofilm Disintegration, Enhanced Foliar Affinity, and Effective Management of Tomato Bacterial Canker

Clavibacter michiganensis (Cmm), designated as an A2 quarantine pest by the European and Mediterranean Plant Protection Organization (EPPO), incites bacterial canker of tomato, which presently eludes rapid and effective control methodologies. Dense biofilms formed by Cmm shield internal bacteria from host immune defenses and obstruct the ingress of agrochemicals. Even when agrochemicals disintegrate biofilms, splashing and bouncing during application disperse active ingredients away from target sites. Herein, we present a supramolecular strategy to fabricate a hexagonal prism-shaped material, BPGA@CB[8], assembled from an 18β-glycyrrhetinic acid derivative (PBGA) and host molecule-cucurbit[8]uril (CB[8]) via host-guest recognition. This positively charged material manifests multifaceted functionalities, notably the ability to surmount biofilm barriers, annihilate the encased pathogenic bacteria, and enhance foliar affinity of droplets. The strong in vitro potency and effective deposition of BPGA@CB[8] foster optimal conditions for robust in vivo efficacy, demonstrating superior protective and curative activities (56.9 %/53.4 %) against canker of tomato at a low-dose of 100 μg⋅mL-1 compared to BPGA (44.6 %/42.2 %), kasugamycin (30.1 %/28.4 %), and thiodiazole copper (35.4 %/31.0 %). This supramolecular material, based on natural product derivatives, provides a potent treatment for high-risk canker of tomato, and exemplifies the utility of supramolecular strategies in optimizing the attributes of natural products for managing plant bacterial diseases.

Self-powered Wraparound (Abaxial) Droplet Deposition via a Superhydrophobic Surface Aid

Many diseases and pests are fond of the backs of leaves, making wraparound deposition essential for enhancing agrochemical utilization and minimizing environmental hazards. We present a superhydrophobic surface decorated with fluorinated-SiO2 nanoparticles on the adaxial (front) side, improving sprayed droplet wraparound behaviors and achieving a 10-fold increase in abaxial (backside) deposition without using an electrostatic sprayer. Solid-liquid contact electrification boosts the positive charge-to-mass ratio of rebound spraying from 17 to 454 nC g-1, with the abaxial surface acquiring opposite electric charges at kilovolt-level voltages. This intensified droplet-solid electrostatic attraction guides droplets to wrap around and deposit on the abaxial surface. Further, a homemade fluorinated superhydrophobic tube enhances spray charge and abaxial deposition density on superhydrophobic plant leaves by 47- and 5- times, respectively, compared to those obtained via direct spraying. This work will significantly improve agrochemical efficiency, reducing environmental risks in sustainable agriculture and related industries.

Smart β-cyclodextrin-dominated helical supramolecular dendritic assemblies improve the foliar affinity and biofilm disruption for treating alarming bacterial diseases

Recent outbreaks of alarming bacterial diseases have significantly impacted global agricultural productivity. Conventional bactericides exhibit certain limitations in efficiently impeding biofilm formation and annihilating biofilm-dispersed pathogens, and often expose to high off-target movement during foliar spraying. Here, we produce an innovative helical dendrimer-like supramolecular material (PhA28@β-CD) assembled by a bioactive small-molecule 2-chlorophenylisopropanolamine (PhA28) and β-cyclodextrin (β-CD) through host-guest recognition principle. In this system, the advisable optimization by a macrocyclic oligosaccharide-β-CD significantly enhances the water-solubility, biocompatibility, and bioavailability of PhA28. At a low-dose of 6.8 μg/mL, PhA28@β-CD discloses an outstanding biofilm disruption rate of 82.4 %, notably exceeding that of PhA28 (60.6 %), which thereby reduces the biofilm-associated virulence. Meanwhile, the self-assembled PhA28@β-CD possesses superior wetting and dispersing properties on hydrophobic leaves, leading to effective foliar deposition and prolong retention of active components. In vivo studies reveal that PhA28@β-CD exhibits superior curative (66.0 %) and protective (72.6 %) activities against citrus canker at 200 μg/mL, markedly surpassing those of the existing bactericide thiodiazole‑copper (46.8 % and 52.2 %) and single PhA28. This material also has broad-spectrum control efficiency (53.0 % ~ 59.5 %) against rice bacterial blight. This research lays the groundwork for developing carbohydrate-optimized multifunctional dendrimer-like assemblies aimed at disrupting biofilms and improving sustained bioavailability to combat bacterial diseases.

Biocompatible Nano-Cocrystal Engineering for Targeted Herbicide Delivery: Enhancing Efficacy through Stimuli-Responsive Release and Reduced Environmental Losses

In addressing the critical challenges posed by the misuse and inefficiency of traditional pesticides, we introduce a Nano-Cocrystal material composed of the herbicide clopyralid and coformer phenazine. Developed through synergistic supramolecular self-assembly and mechanochemical nanotechnology, this Nano-Cocrystal significantly enhances pesticide performance. It exhibits a marked improvement in stability, with reductions in hygroscopicity and volatility by approximately 38%. Moreover, it intelligently modulates release according to environmental factors, such as temperature, pH, and soil inorganic salts, demonstrating decreased solubility by up to four times and improved wettability and adhesion on leaf surfaces. Importantly, the herbicidal activity surpasses that of pure clopyralid, increasing suppression rates of Medicago sativa L. and Oxalis corniculata L. by up to 27% at the highest dosage. This Nano-Cocrystal also shows enhanced crop safety and reduced genotoxicity compared to conventional formulations. Offering a blend of simplicity, cost-effectiveness, and robust stability, our findings contribute a sustainable solution to agricultural practices, favoring the safety of nontarget organisms.

Engineering Entomopathogenic Fungi Using Thermal-Responsive Polymer to Boost Their Resilience against Abiotic Stresses

Entomopathogenic fungi offer an ecologically sustainable and highly effective alternative to chemical pesticides for managing plant pests. However, the efficacy of mycoinsecticides in pest control suffers from environmental abiotic stresses, such as solar UV radiation and temperature fluctuations, which seriously hinder their practical application in the field. Herein, we discovered that the synthetic amphiphilic thermal-responsive polymers are able to significantly enhance the resistance of Metarhizium robertsii conidia against thermal and UV irradiation stresses. The thermosensitive polymers with extremely low cytotoxicity and good biocompatibility can be engineered onto the M. robertsii conidia surface by anchoring hydrophobic alkyl chains. Further investigations revealed that polymer supplementation remarkably augmented the capacity for penetration and the virulence of M. robertsii under heat and UV stresses. Notably, broad-spectrum entomopathogenic fungi can be protected by the polymers. The molecular mechanism was elucidated through exploring RNA sequencing and in vivo/vitro enzyme activity assays. This work provides a novel avenue for fortifying the resilience of entomopathogenic fungi, potentially advancing their practical application as biopesticides.

Lignin/Surfactin Coacervate as an Eco-Friendly Pesticide Carrier and Antifungal Agent against Phytopathogen

Excessive usage of biologically toxic fungicides and their matrix materials poses a serious threat to public health. Leveraging fungicide carriers with inherent pathogen inhibition properties is highly promising for enhancing fungicide efficacy and reducing required dosage. Herein, a series of coacervates have been crafted with lignin and surfactin, both of which are naturally derived and demonstrate substantial antifungal properties. This hierarchically assembled carrier not only effectively loads fungicides with a maximum encapsulation efficiency of 95% but also stably deposits on hydrophobic leaves for high-speed impacting droplets. Intriguingly, these coacervates exhibit broad spectrum fungicidal activity against eight ubiquitous phytopathogens and even act as a standalone biofungicide to replace fungicides. This performance can significantly reduce the fungicide usage and be further strengthened by an encapsulated fungicide. The inhibition rate reaches 87.0% when 0.30 mM pyraclostrobin (Pyr) is encapsulated within this coacervate, comparable to the effectiveness of 0.80 mM Pyr alone. Additionally, the preventive effects against tomato gray mold reached 53%, significantly surpassing those of commercial adjuvants. Thus, it demonstrates that utilizing biosurfactants and biomass with intrinsic antifungal activity to fabricate fully biobased coacervates can synergistically combine the functions of a fungicide carrier and antifungal agent against phytopathogens and guarantee environmental friendliness. This pioneering approach provides deeper insights into synergistically enhancing the effectiveness of agrochemicals from multiple aspects, including fungicide encapsulation, cooperative antifungal action, and droplet deposition.

Smart and Sustainable Crop Protection: Design and Evaluation of a Novel α-Amylase-Responsive Nanopesticide for Effective Pest Control

In this study, an α-amylase-responsive controlled-release formulation was developed by capping polydopamine onto β-cyclodextrin-modified abamectin-loaded hollow mesoporous silica nanoparticles. The prepared Aba@HMS@CD@PDA were subjected to characterization using various analytical techniques. The findings revealed that Aba@HMS@CD@PDA, featuring a loading rate of 18.8 wt %, displayed noteworthy release behavior of abamectin in the presence of α-amylase. In comparison to abamectin EC, Aba@HMS@CD@PDA displayed a significantly foliar affinity and improved rainfastness on lotus leaves. The results of field trail demonstrated a significantly higher control efficacy against Spodoptera litura Fabricius compared to abamectin EC at all concentrations after 7, 14, and 21 days of spaying, showcasing the remarkable persistence of Aba@HMS@CD@PDA. These results underscore the potential of Aba@HMS@CD@PDA as a novel and persistently effective strategy for sustainable on-demand crop protection. The application of nanopesticides can enhance the effectiveness and efficiency of pesticide utilization, contributing to more sustainable agricultural practices.

Ecofriendly Controlled-Release Insecticide Carrier: pH-/Temperature-Responsive Rosin-Derived Hydrogels for Avermectin Delivery against Mythimna separata (Walker)

The exploration of environmentally friendly, less toxic, sustained-release insecticide is increasing with the growing demand for food to meet the requirements of the expanding population. As a sustained-release carrier, the unique, environmentally friendly intelligent responsive hydrogel system is an important factor in improving the efficiency of insecticide utilization and accurate release. In this study, we developed a facile approach for incorporating the natural compound rosin (dehydroabietic acid, DA) and zinc ions (Zn2+) into a poly(N-isopropylacrylamide) (PNIPAM) hydrogel network to construct a controlled-release hydrogel carrier (DA-PNIPAM-Zn2+). Then, the model insecticide avermectin (AVM) was encapsulated in the carrier at a drug loading rate of 36.32% to form AVM@DA-PNIPAM-Zn2+. Surprisingly, the smart controlled carrier exhibited environmental responsiveness, strongly enhanced mechanical properties, self-healing ability, hydrophobicity, and photostability to ensure a balance between environmental friendliness and the precision of the drug release. The release experiments showed that the carboxyl and amide groups in the polymer chains alter the intermolecular forces within the hydrogel meshes and ingredient diffusion by changing temperatures (25 and 40 °C) and pH values (5.8, 7.4, and 8.5), leading to different release behaviors. The insecticidal activity of the AVM@DA-PNIPAM-Zn2+ against oriental armyworms was good, with an effective minimum toxicity toward aquatic animals. Therefore, AVM@DA-PNIPAM-Zn2+ is an effective drug delivery system against oriental armyworms. We anticipate that this ecofriendly, sustainable, smart-response carrier may broaden the utilization rosin and its possible applications in the agricultural sector.

Understanding and Utilizing Droplet Impact on Superhydrophobic Surfaces: Phenomena, Mechanisms, Regulations, Applications, and Beyond

Droplet impact is a ubiquitous liquid behavior that closely tied to human life and production, making indispensable impacts on the big world. Nature-inspired superhydrophobic surfaces provide a powerful platform for regulating droplet impact dynamics. The collision between classic phenomena of droplet impact and the advanced manufacture of superhydrophobic surfaces is lighting up the future. Accurately understanding, predicting, and tailoring droplet dynamic behaviors on superhydrophobic surfaces are progressive steps to integrate the droplet impact into versatile applications and further improve the efficiency. In this review, the progress on phenomena, mechanisms, regulations, and applications of droplet impact on superhydrophobic surfaces, bridging the gap between droplet impact, superhydrophobic surfaces, and engineering applications are comprehensively summarized. It is highlighted that droplet contact and rebound are two focal points, and their fundamentals and dynamic regulations on elaborately designed superhydrophobic surfaces are discussed in detail. For the first time, diverse applications are classified into four categories according to the requirements for droplet contact and rebound. The remaining challenges are also pointed out and future directions to trigger subsequent research on droplet impact from both scientific and applied perspectives are outlined. The review is expected to provide a general framework for understanding and utilizing droplet impact.

Chirality-Selected Coacervate by Chiral Gemini Surfactant

Chiral surfactants present opportunities to self-assemble into supramolecules with a chiral trait; however, the effects of stereochemistry on the formation of simple coacervates remain unclear. Here, we investigate the chirality-selected phase behavior in mixtures of chiral gemini surfactant 1,4-bis(dodecyl-N,N-dimethylammonium bromide)-2,3-butanediol (12-4(OH)2-12) with an oppositely charged chiral mandelic acid (MA). It demonstrates that altering the chirality of surfactants yields a heightened ability to regulate the phase behavior, leading to the formation of three different network-like structures, i.e., wormlike micelle, coacervate, and hydrogel, in the racemate, enantiomer, and mesomer, respectively. The different aggregate structures arise from the intermolecular and intramolecular hydrogen-bond interactions of the two hydroxyl groups located at stereogenic centers. Intriguingly, although they contain similar microstructures, the solid-like hydrogel and liquid-like wormlike micelle show similar low hydration ability and have no encapsulation capability, whereas only coacervate formed by the enantiomers of 12-4(OH)2-12 displays liquid-like characteristics, strong capacity to sequester diverse solutes, and high affinity for tightly bound water simultaneously. These findings further highlight the unique and advantageous properties of coacervates as a promising model for exploring the biological process and understanding how chirality plays a crucial role in early life scenarios and cell evolution at the molecular level.