http://hdl.handle.net/123456789/913 2026-04-14T18:44:00Z http://hdl.handle.net/123456789/217610 Title: pH-responsive λ-cyhalothrin nanopesticides for effective pest control and reduced toxicity to Harmonia axyridis Authors: Hou, Ruiquan; Zhou, Jingtong; Song, Zixia; Zhang, Ning; Huang, Suqing; Amir E. Kaziem; Zhao, Chen; Zhang, Zhixiang Abstract: In this study, pH-responsive LC@O-CMCS/PU nanoparticles were prepared by encapsulating λ-cyhalothrin (LC) with O-carboxymethyl chitosan (O-CMCS) to form LC/O-CMCS and then covering it with polyurethane (PU). Characterization and performance test results demonstrate that LC@O-CMCS/PU had good alkaline release properties and pesticide loading performance. Compared to commercial formulations containing large amounts of emulsifiers (e.g., emulsifiable concentrate, EC), LC@O-CMCS/PU showed better leaf-surface adhesion. On the dried pesticide-applied surfaces, the acute contact toxicity of LC@O-CMCS/PU to Harmonia axyridis (H. axyridis) was nearly 20 times lower than that of LC EC. Due to the slow-releasing property of LC@O-CMCS/PU, only 16.38 % of LC was released at 48 h in dew and effectively reduced the toxicity of dew. On the pesticide-applied leaves with dew, exposure to the LC (EC) caused 86.66 % mortality of H. axyridis larvae significantly higher than the LC@O-CMCS/PU, which was only 16.66 % lethality. Additionally, quantitative analysis demonstrated 11.33 mg/kg of λ-cyhalothrin in the dew on LC@O-CMCS/PU lower than LC (EC) with 4.54 mg/kg. In summary, LC@O-CMCS/PU effectively improves the safety of λ-cyhalothrin to H. axyridis and has great potential to be used in pest control combining natural enemies and chemical pesticides. 2023-02-15T00:00:00Z http://hdl.handle.net/123456789/217607 Title: Effects of Exposure to Different Types of Metal-Organic Framework Nanoparticles on the Gut Microbiota and Liver Metabolism of Adult Zebrafish Authors: Yang, Liupeng; Chen, Huiya; Amir E. Kaziem; Miao, Xiaoran; Huang, Suqing; Cheng, Dongmei; Xu, HanHong; Zhang, Zhixiang Abstract: Metal-organic framework nanoparticles (MOF NPs) have received much attention for their potential use in nanopesticides. However, little is known about the potential health and environmental risks associated with these materials. In this study, the toxicological responses of zebrafish exposed to five MOF NPs for short and long periods of time were evaluated. The acute toxicity results showed that the toxicity of the five MOF NPs to zebrafish embryos and adult zebrafish was in the order of Cu-MOF > ZIF-90 > ZIF-8 > Fe-MOF > Zr-MOF. Histopathological analysis revealed that ZIF-8, ZIF-90, and Cu-MOF NPs caused liver swelling and vacuolization in zebrafish. The cellular ultrastructure showed that ZIF-8, ZIF-90, and Cu-MOF NPs severely damaged the mitochondrial structure in intestinal epithelial cells and liver cells. The 16S rDNA sequencing data showed that all five MOF NPs significantly altered the dominant microorganisms in the zebrafish intestine. The microbial markers of intestinal inflammation, Proteobacteria (Aeromonas, Plesiomonas, and Legionella), were significantly increased in the Fe-MOF, ZIF-8, Zr-MOF, and Cu-MOF treatment groups. Metabolomics results indicated that the levels of inflammatory promoting factors (Leukotriene E4, 20-hydroxyeicosatetraenoic acid) in arachidonic acid metabolism were decreased, and the levels of inflammatory suppressing factors (8,9-epoxyeicosatrienoic acid) were increased. Metabolites related to oxidative stress, such as glutamine, pyridoxamine, and l-glutamic acid in vitamin B6 metabolism and other signaling pathways, were significantly reduced. Overall, these results suggest that the different MOF NPs had widely varying toxicity to zebrafish, and further attention should be paid to the toxicity of MOF NPs in the real environment. 2024-09-17T00:00:00Z http://hdl.handle.net/123456789/217606 Title: pH/Enzyme-responsive nanocarrier pesticide delivery system: Realizing targeted release in pest gut for enhanced Apis cerana safety Authors: Du, Pengrui; Shao, Xuehua; Wu, Hao; Hou, Ruiquan; Liu, Jun; Chang, Jinzhe; Miao, Xiaoran; Wang, Xin; Liu, Pengpeng; Zhu, Shiqi; Amir E. Kaziem; Zhang, Zhixiang; Zhang, Peiwen Abstract: The application of pesticides has significantly reduced the danger of pests to crops. However, the adverse effects of pesticides on non-target organisms pose a significant environmental threat. Here, we constructed bio-based polymer nanoparticles of indoxacarb (IDC) that can be enzymatically released (trypsin and chymotrypsin) according to the intestinal pH of Spodoptera frugiperda and Apis cerana, thereby improving the safety of indoxacarb to non-target organisms. The results showed that the average diameter of IDC@ZOC NPs was 170.9 nm and had dual responses to pH and enzyme activity. In the simulated S. frugiperda intestinal conditions (pH 8.0–10.0), the nanoparticles disintegrated rapidly under higher trypsin/chymotrypsin activities and released a large amount of drugs. Conversely, under simulated honeybee intestinal conditions (pH 4.5–6.5), nanoparticles aggregated under acidic conditions, reducing the rate at which the nanoparticles were hydrolyzed by proteases. Bioassay results showed that IDC@ZOC NPs were 1.9 times as toxic to S. frugiperda larvae as IDC WP, caused severe damage to the midgut and affected larval growth, development and oxidative stress activity. Notably, the toxicity of IDC@ZOC NPs to honeybees was reduced by 3.09 times compared to IDC WP, significantly reducing the effects on honeybee growth and development. In addition, the increased levels of DCJW in S. frugiperda larval midgut confirmed the enhanced efficacy of IDC@ZOC NPs. In summary, our results propose a nanopesticide delivery system that responds to changes in pH and proteases in the guts of pests and honeybees, providing a new strategy for pest management through an innovative pesticide delivery system. 2025-01-01T00:00:00Z http://hdl.handle.net/123456789/217604 Title: pH-Responsive lignin-modified copper-based metal-organic frameworks for precision thiamethoxam delivery in the targeted control of red imported fire ants (Solenopsis invicta) Authors: Liu, Pengpeng; Amir E. Kaziem; Li, Chen; Wang, Xin; Zhu, Shiqi; Chang, Jinzhe; Cheng, Dongmei; Xu, Han Hong; Zhang, Zhixiang; Yang, Liupeng Abstract: The red imported fire ant (RIFA), Solenopsis invicta, is a globally invasive pest, posing a significant challenge in developing effective control strategies. HKUST-1, a classical metal–organic framework (MOF), holds potential in pest control; however, its water instability limits its practical application. In this study, we address this limitation by synthesizing lignin-modified metal–organic frameworks (L/HKUST-1), using alkaline lignin as a biopolymer carrier in a one-pot synthesis process. The effects of various temperatures, stirring speeds, and lignin concentrations on the morphology and particle size of L/HKUST-1 were systematically investigated. The resulting L/HKUST-1 exhibited an octahedral morphology with an average particle size of 530 nm, along with improved water stability and a thiamethoxam (TMX) loading rate of 26.5 %. A pH-responsive pesticide delivery system (TMX@L/HKUST-1) was developed using L/HKUST-1 as the carrier and TMX, a neonicotinoid insecticide, as the active ingredient. This system effectively controls RIFA by precisely delivering TMX in response to the acidic pH environment of the RIFA gut. In vitro release kinetics demonstrated that TMX@L/HKUST-1 rapidly releases TMX under pH 4.5 conditions. Bioassay results revealed that TMX@L/HKUST-1 significantly enhances toxicity against RIFA by increasing feeding activity and causing damage to intestinal cells. The LC<inf>50</inf> of TMX@L/HKUST-1 was 1.225 mg/L (24 h) and 0.3164 mg/L (48 h), respectively. The system also inhibited key enzymes in detoxification and oxidative stress in RIFA. Furthermore, 16S rDNA analysis showed that TMX@L/HKUST-1 reduced the relative abundance of Serratia, while increasing the abundance of Pseudomonas and Bacillus, thereby weakening RIFA's resistance to pesticides and pathogens. These findings suggest that TMX@L/HKUST-1 is a promising nanopesticide delivery system, offering a novel approach for the efficient control of invasive species such as RIFA. 2025-01-01T00:00:00Z