Enhanced and sustained pesticidal activity of a graphene-based pesticide delivery system against the diamondback moth Plutella xylostella

An Iron-Based Metal-Organic Framework as Nanocarrier for Lambda-Cyhalothrin Delivery: pH-Responsive Controlled Release, Enhanced Leaf Adhesion, and Prolonged Duration Period against Culex pipiens pallens

Lambda-Cyhalothrin (LC) is a high-efficiency and broad-spectrum insecticide. However, due to its poor water dispersion stability and unstable efficacy, it has many problems in practical applications. Therefore, there is an urgent need to develop new formulations with stability, low toxicity, and environmental friendliness to overcome the drawbacks of traditional pesticide formulations. This study designed an iron-based metal-organic framework (MIL-101(Fe)) as a nanocarrier for the loading of LC and then surface modified it with polydopamine (PDA) to form the nanopesticide PDA-LC-MIL. The results showed that PDA-LC-MIL has good stability and can achieve controlled release of pesticide by adjusting the pH value. In addition, it also has a good leaf affinity and can effectively adhere on crop leaves, improving the utilization rate of pesticides. The insecticidal experimental results indicate that PDA-LC-MIL has significantly improved sustained insecticidal activity. PDA-LC-MIL also has good biocompatibility and shows no significant inhibitory effect on seed germination and seedling growth of Vigna radiata (L.) Wilczek and maize. Therefore, we firmly believe that MIL-based nanopesticides will have broad application prospects in the field of green pesticides and modern agriculture.

Graphene oxide enhances aphid resistance in sorghum via the miR319-SbTCP7-SbLOX3 Pathway

The aphid (Melanaphis sacchari) has emerged as a formidable pest, devastating sorghum plants and highlighting the need for sustainable management strategies. Graphene oxide (GO), as a novel material, has garnered attention for its use in crop cultivation and management, but its effects on biotic stresses remain elusive. Here, we used 10 mg/L GO to spray aphid-stressed sorghum seedlings four times in total. GO exposure reduced 50% H2O2 from the reactive oxygen species (ROS) burst induced by the aphid. Further analysis revealed that GO within the cells acts as a nanozyme, mimicking and enhancing the catalytic activity of the ROS-scavenging system to maintain ROS homeostasis, protecting normal plant growth and development under aphid stress. Moreover, the moderate increase in H2O2 in GO-treated, aphid-infected seedlings blocked the biogenesis of miR319, leading to the induction of its target gene SbTCP7, which in turn activated the transcription of SbLOX3, a rate-limiting enzyme in jasmonic acid (JA) biosynthesis. Subsequent molecular and genetic assays confirmed that the miR319-SbTCP7 module enhances JA metabolism, promoting the accumulation of JA and its active derivative jasmonic acid-isoleucine (JA-Ile) to combat aphids. Our results suggest that GO, as a potential nanozyme, enhances the aphid resistance of sorghum through the miR319-SbTCP7 module to regulate JA synthesis, indicating a novel cultivation strategy for improving pest management via nanomaterials. This frontier research has opened new avenues for crop protection against invasive pests like aphids.

Exploring the Capabilities of Nanosized Graphene Oxide as a Pesticide Nanosorbent: Simulation Studies

The pesticide contamination in the environment has become a global concern. So far, pesticide adsorption from waste solution is one of the most economic strategies for pesticide removal. Carbon-based nanomaterials were reported to be potential pesticide sorbents. To date, nanosized graphene oxide (GO) has been discovered. Its nanosize, which is comparable to pesticide sizes, is attractive enough to explore its performance to be the pesticide sorbent. Thus, herein, the adsorption mechanisms of a single pesticide on GO were studied by comparing 6-pesticide systems. Three types of common pesticides (cyfluthrin (CFT) (pyrethroid), ivermectin (IVM) (avermectin), and diazinon (DZ) (organophosphate)) were used as pesticide models. All pesticides rapidly adhere to GO at the graphene-like region. The π-π and π-alkyl interactions contribute most to pesticide adhesion. The adsorption of CFT and DZ is led by the π-π stacking, whereas bulky IVM uses the π-alkyl forces. Having more pesticides results in self-clustering. Pesticides pile up and avoid lying on the oxygenated area. IVM is the most favorable for GO and shows tight self-packing via dispersion force and hydrogen bonding. Overall, this work displays the encouraging ability of nanosized GO to effectively absorb all pesticides which will benefit future applications in pest control.

Effects of copper/graphene oxide core-shell nanoparticles on Rhipicephalus ticks and their detoxification enzymes

Nanopesticides have been recently introduced as novel pesticides to overcome the drawbacks of using traditional synthetic pesticides. The present study evaluated the acaricidal activity of Copper/Graphene oxide core-shell nanoparticles against two tick species, Rhipicephalus rutilus and Rhipicephalus turanicus. The Copper/Graphene oxide core-shell nanoparticles were synthetized through the solution plasma (SP) method under different conditions. The nanoparticles synthesized at 180 W and 45 min were highly toxic to Rh. rutilus and Rh. turanicus, with 50% lethal concentration (LC50) values of 248.1 and 195.7 mg ml-1, respectively, followed by those which were synthesized at 120 W/30 mins (LC50 = 581.5 and 526.5 mg ml-1), 120 W/15 mins (LC50 = 606.9 and 686.7 mg ml-1), and 100/45 mins (LC50 = 792.9 and 710.7 mg ml-1), after 24 h of application. The enzyme assays revealed that 180 W/45 min treatment significantly inhibited the activity of acetylcholinesterase (115 ± 0.81 and 123 ± 0.33 U/ mg protein/min) and superoxide dismutase (290 ± 0.18 and 310 ± 0.92 U/ mg protein/min) in Rh. rutilus and Rh. turanicus, respectively, as compared with the negative control. The results also revealed a significantly increased catalase activity (895 ± 0.37 and 870 ± 0.31 U/ mg protein/min) in Rh. rutilus and Rh. turanicus, respectively. The above results indicated that Copper/Graphene oxide core-shell nanoparticles could be a promising alternatives for the management of ticks.

Joint Toxicity and Interaction of Carbon-Based Nanomaterials with Co-Existing Pollutants in Aquatic Environments: A Review

This review paper focuses on the joint toxicity and interaction of carbon-based nanomaterials (CNMs) with co-existing pollutants in aquatic environments. It explores the potential harmful effects of chemical mixtures with CNMs on aquatic organisms, emphasizing the importance of scientific modeling to predict mixed toxic effects. The study involved a systematic literature review to gather information on the joint toxicity and interaction between CNMs and various co-contaminants in aquatic settings. A total of 53 publications were chosen and analyzed, categorizing the studies based on the tested CNMs, types of co-contaminants, and the used species. Common test models included fish and microalgae, with zebrafish being the most studied species. The review underscores the necessity of conducting mixture toxicity testing to assess whether the combined effects of CNMs and co-existing pollutants are additive, synergistic, or antagonistic. The development of in silico models based on the solid foundation of research data represents the best opportunity for joint toxicity prediction, eliminating the need for a great quantity of experimental studies.

Functionally Modified Graphene Oxide as an Alternative Nanovehicle for Enhanced dsRNA Delivery in Improving RNAi-Based Insect Pest Control

RNA interference (RNAi) has shown substantial promise as a sustainable pest management solution. However, the efficacy of RNAi-based insecticides heavily relies on advanced nanocarrier-mediated delivery systems. In this study, we modified raw graphene oxide into positively charged nanocarriers (GONs) tailored to bind with double-stranded RNA (dsRNA). The resulting GONs@dsRNA complexes demonstrated a small particle size (106 nm) and maintained stability under various conditions, including insect gut extracts, extreme pH, and extreme temperature. Furthermore, GONs efficiently transported dsRNA molecules into Drosophila S2 cells and Lepidoptera Sf9 cells, leading to an enhanced target transcript knockdown. Targeting the vacuolar ATPase gene, vha26, induced significant mortality and target transcript knockdown in D. suzukii adults but not in S. exigua. Finally, GONs@dsRNA complexes exhibited negligible cytotoxicity at both the cellular and organismal levels. This study demonstrates the potential of GONs as a biosafe nanovehicle for efficient dsRNA delivery into insects, presenting an alternative strategy for advancing RNAi applications in fundamental studies and pest control.

Redox/Near-Infrared Dual-Responsive Hollow Mesoporous Organosilica Nanoparticles for Pesticide Smart Delivery

Extremely inefficient utilization of pesticides has prompted a study of low-cost, sustainable, and smart application systems. Herein, as a promising pesticide nanocarrier, hollow mesoporous organosilica nanoparticles (HMONs) were first synthesized by using inexpensive CaCO3 nanoparticles as the hollow templates. A redox/near-infrared light dual-triggered pesticide release system was further achieved via loading avermectin (AVM) into the HMONs and coating a layer of polydopamine (PDA). The as-prepared AVM@HMONs@PDA displays a favorable pesticide load capability (24.8 wt %), outstanding photothermal performance, and high adhesion to leaves. In addition, with glutathione (GSH), the AVM cumulative release from AVM@HMONs@PDA was 3.5 times higher than that without GSH. Under ultraviolet light irradiation, the half-life of AVM@HMONs@PDA was prolonged by 17.0-fold compared to that of the AVM technical. At day 21 after treatment in the insecticidal activity, the median lethal concentrations (LC50) values displayed that the toxicity of AVM@HMONs@PDA for Panonychus citri (McGregor) was enhanced 4.0-fold compared with the commercial emulsifiable concentrate. In the field trial, at day 28 after spraying, AVM@HMONs@PDA was significantly more control effective than AVM-EC in controlling the P. citri (McGregor), even at a 50% reduced dosage. Moreover, HMONs@PDA was safe for crops. This research presents a novel preparation approach for HMONs, and it also offers a promising nanoplatform for the precise release of pesticides.

Preparation and Characterization of Insecticide/Calix[4]arene Complexes and Their Enhanced Insecticidal Activities against Plutella xylostella

Applications of supramolecular materials in plant protection have attracted significant interest in recent years. To develop a feasible method to improve the efficacy and reduce the usage of chemical pesticides, the effect of calix[4]arene (C4A) inclusion on enhancing the insecticidal activity of commercial insecticides was investigated. Results showed that all three tested insecticides (chlorfenapyr, indoxacarb, and abamectin) with distinct molecular sizes and modes of action were able to form stable 1:1 host-guest complexes with C4A through simple preparation steps. The insecticidal activities of the complexes against Plutella xylostella were effectively enhanced compared to the guest molecule, with the synergism ratio being up to 3.05 (for indoxacarb). An obvious correlation was found between the enhanced insecticidal activity and the high binding affinity between insecticide and C4A, while the improvement in water solubility may not be a determining factor. The work would provide hints for the further development of functional supramolecular hosts as synergists in pesticide formulations.