Mesoporous silica size, charge, and hydrophobicity affect the loading and releasing performance of lambda-cyhalothrin

Optimized nanopesticide delivery of thiamethoxam to cowpeas (Vigna unguiculata) controls thrips (Megalurothrips usitatus) and reduces toxicity to non-target worker bees (Apis mellifera)

Thrips [Megalurothrips usitatus (Bagnall)] (Thysanoptera: Thripidae) is a pest that poses a serious challenge to global crop production and food supply, especially to the cowpea industry. Nano-delivery systems have broad application prospects in the prevention and control of pests in agriculture. Herein, three types of amino acid (AA) modified polysuccinimide nano-delivery carriers (PSI-GABA, PSI-ASP and PSI-GLU) were constructed with a diameter of approximately 150 nm to load thiamethoxam (THX), which enhanced THX effective distribution and use with cowpea plants. Significantly, the PSI-GLU nanocarrier effectively delivered THX to cowpea plant tissues following 6 h of soil application. Compared with commercial THX suspension (SC), the THX content in the leaves of cowpea plants was increased by 2.3 times. Confocal laser scanning microscopy revealed that the FITC-labeled PSI-GLU nanocarrier reached the leaves through the vascular system after being absorbed by the roots of cowpea plants. The PSI-GLU nanocarrier decreased the LC50 of THX from 11.45 to 7.79 mg/L and significantly enhanced the insecticidal effect. The PSI-GLU nanocarrier also improved the safety of THX to worker bees at 48 h, and moreover showed a growth-promoting effect on cowpea seedlings. These results demonstrated that the PSI-GLU nano-delivery carrier has promising uses on improving the effective utilization of THX for the sustainable control of thrips and reducing the risk to non-target pollutions.

High deposition and precise stimulus-response release performance of lignin-coated dendritic mesoporous organosilica nanoparticles for efficient pesticide utilization

The inefficient and improper use of conventional pesticides has prompted the development of targeted and cost-effective pesticide delivery systems, which aim to optimize the efficient utilization of pesticides while minimizing environmental pollution in surrounding areas. In this paper, a dual-stimuli-responsive pesticide slow-release nanopesticide system (NES@DMONs@LGN) was designed in this study, utilizing mesoporous silica (DMONs) as a nanocarrier and lignin (LGN) as a capping agent to encapsulate the pesticide molecules within DMONs. This system enables intelligent release of pesticide molecules while preventing environmental pollution caused by leakage. Additionally, NES@DMONs@LGN exhibit excellent specific loading efficiency. The abundant hydrophilic functional groups in the lignin layer on the surface of NES@DMONs@LGN can establish hydrogen bonds with advanced fatty acids and fatty alcohols present in the waxy epidermis of plants, thereby significantly enhancing carrier wettability and adhesion. Typically, phytophagous lepidopteran pests have an alkaline midgut and possess lignin-degrading enzymes. The NES@DMONs@LGN developed in this study are capable of rapid release under high temperature and alkaline conditions. Therefore, the precise release of pesticide molecules in the target pests can be achieved, thus increasing the actual utilization rate of pesticides. The experimental results demonstrated that NES@DMONs@LGN effectively prevented photodegradation of the active ingredient after 48 h of UV irradiation, resulting in a 3.7-fold improvement in photostability and providing robust UV protection. By encapsulating pesticide molecules with nanocarriers, the release of pesticides in non-targeted environments can be prevented, thereby significantly reducing toxicity to zebrafish. Thus, this study provides a promising solution for sustainable greening of agriculture.

The Developmental Toxicity and Endocrine-Disrupting Effects of Fenpropathrin on Gobiocypris rarus during the Early Life Stage

In the present study, the developmental toxicity and endocrine-disrupting effects of fenpropathrin on Gobiocypris rarus during the early life stage were studied using a semi-static water exposure method. The results showed that the LOEC (lowest observed effect concentration) of fenpropathrin on the incubation of rare minnow embryos was above 2.5 μg·L-1. The LOEC and NOEC (no observed effect concentration) of fenpropathrin on the developmental malformations and death indicators were 2.0 and 1.5 μg·L-1, respectively. After exposure to 1.5 μg·L-1 of fenpropathrin for 31 days, the expressions of androgen receptor genes (AR) and sex hormone-synthesis-related genes (CYP17 and CYP19a) were significantly decreased and the expressions of thyroid hormone receptor genes (TRβ) and aryl hydrocarbon receptor genes (AhR1a and AhR2) were significantly increased in juvenile Gobiocypris rarus. The expression levels of the androgen receptor gene (AR), estrogen receptor gene (ER1), and the sex hormone-synthesis-related genes (HMGR, CYP17, and CYP19a) were significantly decreased, while the estrogen receptor gene (ER2a), thyroid hormone receptor gene (TRβ), and aromatic hydrocarbon receptor genes (AhR1a and AhR2) were upregulated in juvenile Gobiocypris rarus under exposure to 2.0 μg·L-1 of fenpropathrin. Relatively low concentrations of fenpropathrin can affect the expression of sex hormone receptor genes, genes related to sex hormone synthesis, thyroid hormone receptor genes, and aromatic hydrocarbon receptor genes, thus interfering with the reproductive system, thyroid system, and metabolic level in Gobiocypris rarus. Therefore, more attention should be paid to the endocrine-disrupting effect caused by the pyrethroid insecticides in the water environment. Furthermore, studies on the internal mechanism of the endocrine-disrupting effect of pyrethroid insecticides on fish is needed in the future.

A mesoporous silica nanocarrier pesticide delivery system for loading acetamiprid: Effectively manage aphids and reduce plant pesticide residue

A multifunctional nanomaterials-based agrochemical delivery system could supply a powerful tool for the efficient use of pesticides. Redox-responsive carriers as novel delivery systems of pesticide application in agriculture could promote the pest control and reduce plant pesticide residues due to the controllable release of agrochemicals. Herein, neonicotinoid insecticide acetamiprid (Ace) was encapsulated with decanethiol in a mesoporous silica nanocarrier pesticide delivery system for a nanopesticide Ace@MSN-SS-C10. The Ace@MSN-SS-C10 had redox-responsive sustained release behavior triggered by glutathione (GSH). Moreover, the Ace@MSN-SS-C10 possessed excellent wettability, adhesion performance, stability, and biosafety. Greenhouse experiments showed that foliar spraying 1.5 mg Ace@MSN-SS-C10 per plant reduced the populations of adult and juvenile aphids (Aphis craccivora Koch) on Vicia faba L. after 5 days of aphid infestation by 98.7 % and 99.3 %, respectively. Notably, the leaf final Ace residue (0.32 ± 0.004 mg/kg) of Ace@MSN-SS-C10 application at the dose of 1.5 mg/plant after 5 days of aphid infestation was lower than the international Codex Alimentarius Commission (CAC) maximum residue limits (0.4 mg·kg^-1) or much lower (24.87-folds decrease) than those treated with conventional Ace (40 % acetamiprid water dispersible granule). Altogether, this GSH-dependent redox-responsive delivery system for loading acetamiprid can develop as an efficient and environmentally-friendly nanopesticide to control aphids in sustainable agriculture.

Quantifying How Drug-Polymer Interaction and Volume Phase Transition Modulate the Drug Release Kinetics from Core-Shell Microgels

This paper presents a simple experimental-informed theory describing the drug release process from a temperature-responsive core-shell microgel. In stark contrast to the commonly employed power-law models, we couple electric, hydrophobic, and steric factors to characterize the impact of drug-polymer pair interaction on the release kinetics. To this end, we also propose a characteristic time, depicting the drug release process as an interplay between kinetics and thermodynamics. In some instances, the negative correlation between the diffusivity and the (thermodynamics) drug-polymer interaction renders the drug release time non-trivial. In conclusion, our theory establishes a mechanistic understanding of the drug release process, exploring the effect of (hydrophobic adhesion) attractive and (steric exclusion) repulsive pair interactions between the drugs and the microgel in the presence of temperature-induced volume phase transition.