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1.
ACS Appl Mater Interfaces ; 13(33): 39066-39075, 2021 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-34387079

RESUMO

A controlled release formulation based on silica microcapsules is an ideal selection to improve both the effective utilization and duration of pesticides to decrease ecological damage. Herein, a simple and green method for preparing double-shelled microcapsules was developed using a newly prepared quaternary ammonium ionic liquid (IL) as the functional additive to entrap avermectin (Ave) in mesoporous silica nanospheres (MSNs) and tannic acid-Cu (TA-Cu) complex as the sealing agent to form the core-shell structure (Ave-IL@MSN@TA-Cu). The obtained microcapsules with an average size of 538 nm had pH-responsive release property and good stability in soil. The half-life of microcapsules (34.66 days) was 3 times that of Ave emulsifiable concentrate (EC) (11.55 days) in a test soil, which illustrated that microcapsules could protect Ave from rapid degradation by microorganisms by releasing TA, copper, and quaternary ammonium in the soil. Ave-IL@MSN@TA-Cu microcapsules had better nematicidal activity and antibacterial activity than Ave EC due to the synergistic effect of Ave, IL, and copper incorporated in the microcapsules. Pot experiments showed that the control efficacy of microcapsules was 87.10% against Meloidogyne incognita, which is better than that of Ave EC (41.94%) at the concentration of 1.0 mg/plant by the root-irrigation method after 60 days of treatment owing to the extended duration of Ave in microcapsules. The simple and green method for the preparation of double-shelled microcapsules based on natural quaternary ammonium IL would have tremendous potential for the extensive development of controlled release pesticide formulations.


Assuntos
Cápsulas/química , Preparações de Ação Retardada/química , Controle de Pragas/métodos , Praguicidas/química , Dióxido de Silício/química , Tylenchoidea/efeitos dos fármacos , Animais , Complexos de Coordenação/química , Cobre/química , Preparações de Ação Retardada/farmacologia , Composição de Medicamentos , Liberação Controlada de Fármacos , Química Verde , Concentração de Íons de Hidrogênio , Líquidos Iônicos/química , Ivermectina/análogos & derivados , Ivermectina/química , Ivermectina/farmacologia , Praguicidas/farmacologia , Porosidade , Compostos de Amônio Quaternário/química , Solubilidade , Taninos/química , Fatores de Tempo
2.
J Agric Food Chem ; 69(23): 6485-6494, 2021 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-34077226

RESUMO

Silver nanoparticles (AgNPs) have remarkable and broad-spectrum antibacterial activities against Gram-positive (G+) and Gram-negative bacteria (G-). However, the negative surface potential of AgNPs limits their antibacterial activities due to the electrostatic repulsion with the negatively charged bacterial cell membrane. To address the limitation, AgNPs were loaded in the mesoporous silica nanoparticles by preparing silver core-mesoporous silica shell nanocapsules (Ag@MSNs), and then, a cationic antibacterial polymer, quaternary ammonium polyethyleneimine (QPEI), was used to modify Ag@MSNs for improving their surface potential and antibacterial activities. The results showed that the obtained Ag@MSN-QPEI exhibited a high positive surface potential (+39.6 mV) and a strong electrostatic attraction with Pseudomonas syringae pv. lachrymans cells in coculture, resulting in an excellent bacterial cell-targeting effect. At the same concentration, Ag@MSN-QPEI exhibited less silver content (reducing the silver content of Ag@MSNs by 19%), higher antibacterial activities, and longer effective duration against Clavibacter michiganensis subsp. michiganensis (G+) and P. syringae pv. lachrymans (G-) than Ag@MSNs and QPEI alone. The excellent bacterial cell-targeting effect and synergistic antibacterial action combined with QPEI accounted for the significantly enhanced antibacterial activities of Ag@MSN-QPEI. Therefore, using a cationic antibacterial polymer to confer the bacterial cell-targeting effect and synergistic antibacterial action would be extended to other antimicrobial materials.


Assuntos
Compostos de Amônio , Nanopartículas Metálicas , Nanocápsulas , Antibacterianos/farmacologia , Testes de Sensibilidade Microbiana , Polietilenoimina , Dióxido de Silício , Prata/farmacologia
3.
Sci Total Environ ; 787: 147422, 2021 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-33991920

RESUMO

In this work, a pH-responsive pesticide delivery system using mesoporous silica nanoparticles (MSNs) as the porous carriers and coordination complexes of Cu ions and tannic acid (TA-Cu) as the capping agent was established for controlling pyraclostrobin (PYR) release. The results showed the loading capacity of PYR@MSNs-TA-Cu nanoparticles for pyraclostrobin was 15.7 ± 0.5% and the TA-Cu complexes deposited on the MSNs surface could protect pyraclostrobin against photodegradation effectively. The nanoparticles had excellent pH responsive release performance due to the decomposition of TA-Cu complexes under the acid condition, which showed 8.53 ± 0.37%, 82.38 ± 1.67% of the encapsulated pyraclostrobin were released at pH 7.4, pH 4.5 after 7 d respectively. The contact angle and adhesion work of PYR@MSNs-TA-Cu nanoparticles on rice foliage were 86.3° ± 2.7° and 75.8 ± 3.1 mJ/m2 after 360 s respectively, indicating that TA on the surface of the nanoparticles could improve deposition efficiency and adhesion ability on crop foliage. The control effect of PYR@MSNs-TA-Cu nanoparticles against Rhizoctonia solani with 400 mg/L of pyraclostrobin was 85.82% after 7 d, while that of the same concentration of pyraclostrobin EC was 53.05%. The PYR@MSNs-TA-Cu nanoparticles did not show any phytotoxicity to the growth of rice plants. Meanwhile, the acute toxicity of PYR@MSNs-TA-Cu nanoparticles to zebrafish was decreased more than 9-fold compared with that of pyraclostrobin EC. Thus, pH-responsive PYR@MSNs-TA-Cu nanoparticles have great potential for enhancing targeting and environmental safety of the active ingredient.


Assuntos
Nanopartículas , Peixe-Zebra , Animais , Meio Ambiente , Concentração de Íons de Hidrogênio , Porosidade , Rhizoctonia , Dióxido de Silício , Estrobilurinas
4.
J Hazard Mater ; 414: 125513, 2021 07 15.
Artigo em Inglês | MEDLINE | ID: mdl-34030404

RESUMO

The controlled release of pesticides based on nanoparticle platforms has emerged as a new technology for increasing the efficiency of pesticides and for reducing environmental pollution because of their size-dependent and target-modifying properties. In the present study, pH/cellulase dual stimuli-responsive controlled-release formulations (PYR-HMS-HPC) were designed by grafting hydroxypropyl cellulose onto pyraclostrobin-loaded hollow mesoporous silica nanoparticles via an ester linkage. The PYR-HMS-HPC formulations were characterized by Fourier transform infrared spectroscopy, thermogravimetric analyzer, transmission electron microscope and scanning electron microscope. The results demonstrated that PYR-HMS-HPC with a loading capacity of 12.1 wt% showed excellent pyraclostrobin release behaviors in response to acidic environments and the introduction of cellulase, could effectively prevented pyraclostrobin from photolysis. Compared with commercial pyraclostrobin formulations, the PYR-HMS-HPC formulations showed much stronger and statistically significant fungicidal activity against Magnaporthe oryzae from 7 to 21 days. Furthermore, the Allium cepa chromosome aberration assay demonstrated that the PYR-HMS-HPC formulations reduced the genotoxicity of pyraclostrobin. These pH/cellulase dual stimuli-responsive controlled-release formulations are of great interest for sustainable on-demand crop disease protection.


Assuntos
Fungicidas Industriais , Nanopartículas , Ascomicetos , Celulose/análogos & derivados , Portadores de Fármacos , Porosidade , Dióxido de Silício
5.
J Agric Food Chem ; 69(8): 2382-2391, 2021 Mar 03.
Artigo em Inglês | MEDLINE | ID: mdl-33605718

RESUMO

Considering the severity of plant pathogen resistance toward commonly used agricultural microbicides, as well as the potential threats of agrichemicals to the eco-environment, there is a pressing need for antimicrobial approaches that are capable of inactivating pathogens efficiently without the risk of inducing resistances and harm. In this work, a porphyrin metal-organic framework (MOF) nanocomposite was constructed by incorporating 5,10,15,20-tetrakis(1-methyl-4-pyridinio)porphyrin tetra(p-toluenesulfonate) (TMPyP) as a photosensitizer (PS) in the cage of a variant MOF (HKUST-1) to efficiently produce singlet oxygen (1O2) to inactivate plant pathogens under light irradiation. The results showed that the prepared PS@MOF had a loading rate of PS about 12% (w/w) and excellent and broad-spectrum photodynamic antimicrobial activity in vitro against three plant pathogenic fungi and two pathogenic bacteria. Moreover, PS@MOF showed outstanding control efficacy against Sclerotinia sclerotiorum on cucumber in the pot experiment. Allium cepa chromosome aberration assays and safety evaluation on cucumber and Chinese cabbage indicated that PS@MOF had no genotoxicity and was safe to plants. Thus, porphyrin MOF demonstrated a great potential as an alternative and efficient new microbicide for sustainable plant disease management.


Assuntos
Anti-Infecciosos , Estruturas Metalorgânicas , Porfirinas , Anti-Infecciosos/farmacologia , Ascomicetos , Gerenciamento Clínico , Fármacos Fotossensibilizantes/farmacologia , Porfirinas/farmacologia
6.
J Hazard Mater ; 389: 122075, 2020 05 05.
Artigo em Inglês | MEDLINE | ID: mdl-31972522

RESUMO

It is highly desirable to construct stimuli-responsive nanocarriers for improving pesticides targeting and preventing the pesticides premature release. In this work, a novel redox and α-amylase dual stimuli-responsive pesticide delivery system was established by bonding functionalized starch with biodegradable disulfide-bond-bridged mesoporous silica nanoparticles which loaded with avermectin (avermectin@MSNs-ss-starch nanoparticles). The results demonstrated that the loading capacity of avermectin@MSNs-ss-starch nanoparticles for avermectin was approximately 9.3 %. The starch attached covalently on the mesoporous silica nanoparticles could protect avermectin from photodegradation and prevent premature release of active ingredient. Meanwhile, the coated starch and disulfide-bridged structure of nanoparticles could be decomposed and consequently release of the avermectin on demand when nanoparticles were metabolized by glutathione and α-amylase in insects. The bioactivity survey confirmed that avermectin@MSNs-ss-starch nanoparticles had a longer duration in controlling Plutella xylostella larvae compared to avermectin emulsifiable concentrate. In consideration of the superior insecticidal activity and free of toxic organic solvent, this target-specific pesticide release system has promising potential in pest management.


Assuntos
Portadores de Fármacos/química , Inseticidas/toxicidade , Ivermectina/análogos & derivados , Nanopartículas/química , Dióxido de Silício/química , Amido/química , Animais , Portadores de Fármacos/síntese química , Portadores de Fármacos/metabolismo , Portadores de Fármacos/efeitos da radiação , Liberação Controlada de Fármacos , Estabilidade de Medicamentos , Glutationa/metabolismo , Concentração de Íons de Hidrogênio , Inseticidas/efeitos da radiação , Ivermectina/efeitos da radiação , Ivermectina/toxicidade , Cinética , Luz , Mariposas/efeitos dos fármacos , Mariposas/enzimologia , Nanopartículas/efeitos da radiação , Oxirredução , Controle de Pragas/métodos , Porosidade , Dióxido de Silício/efeitos da radiação , Amido/metabolismo , Amido/efeitos da radiação , alfa-Amilases/metabolismo
7.
J Hazard Mater ; 359: 213-221, 2018 10 05.
Artigo em Inglês | MEDLINE | ID: mdl-30036751

RESUMO

α-Amylase-responsive carrier for controlled release of avermectin (AVM) was prepared based on α-cyclodextrin (α-CD) anchored hollow mesoporous silica (HMS) using α-CD as a capping molecule. The release of AVM was studied at different temperatures, pH values and in the presence or absence of α-amylase. The results revealed that the AVM-encapsulated controlled release formulation (AVM-CRF) has a drastic enzymatic dependence, an excellent encapsulation efficacy reaching 38%, and outstanding UV and thermal shielding ability. The AVM-CRF biological activity survey shows excellent toxicological properties against Plutella xylostella larvae, which confirms that α-CD caps could be uncapped enzymatically in vivo and release AVM, inducing P. xylostella larval death. AVM-CRF has a notable capability to keep 0.6 mg L-1 AVM biologically active until 14th day with 83.33% mortality of the target insect, which was 40% higher than that of treated with AVM commercial formulation. The study provides a theoretical basis for the application of pesticide reduction.


Assuntos
Portadores de Fármacos/administração & dosagem , Inseticidas/administração & dosagem , Ivermectina/análogos & derivados , Dióxido de Silício/administração & dosagem , alfa-Amilases/metabolismo , alfa-Ciclodextrinas/administração & dosagem , Animais , Ivermectina/administração & dosagem , Larva/efeitos dos fármacos , Lepidópteros/efeitos dos fármacos , Porosidade
8.
J Nanosci Nanotechnol ; 18(10): 7058-7063, 2018 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-29954533

RESUMO

The porous SnO2 nanospheres were fabricated by hydrothermal method and then the carbon layer was coated as a buffer cushion through a facile hydrothermal process in aqueous D-glucose followed by a subsequent calcination at 500 °C in a nitrogen (N2) atmosphere. The materials were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), thermogravimetric analysis and Raman spectra. Based on the experimental results, the thickness of carbon layer could be well-controlled by hydrothermal time and D-glucose concentration. The typical as-prepared carbon-coated porous SnO2 nanospheres show an initial discharge capacity of 711.26 mAhg-1 and a stabilized capacity at 414 mAhg-1 after 50 cycles. It was shown that the carbon-coated porous SnO2 nanospheres exhibited better electrochemical properties in terms of high Columbic efficiency and rate performance, which are attributed to the porous structure and the outer carbon layer.

9.
J Agric Food Chem ; 65(36): 7854-7864, 2017 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-28809107

RESUMO

In the present study, enzymatic responsive controlled release formulations (CRFs) were fabricated. The CRFs were achieved by anchoring mechanically interlocked molecules using α-cyclodextrin onto the surface pore rims of hollow mesoporous silica (HMS). The CRFs were characterized using Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, and thermogravimetric analysis. The results showed that the CRFs had extraordinary loading ability for chlorantraniliprole (42% w/w) and could effectively preserve chlorantraniliprole against degradation under thermal conditions and UV radiation. The CRFs have been proven to be enzyme-sensitive. The release ratio of chlorantraniliprole from CRFs can be accelerated observably when external α-amylase was introduced. The persistence of CRFs was evaluated by regular sampling feeding experiment using Plutella xylostella as the target insect. The results showed that the larval mortality of P. xylostella was much higher than that of Coragen under all concentrations after 14 days, which proved that CRFs had remarkable persistence.


Assuntos
Preparações de Ação Retardada/síntese química , Preparações de Ação Retardada/farmacologia , Inseticidas/síntese química , Inseticidas/farmacologia , Mariposas/efeitos dos fármacos , alfa-Amilases/química , Animais , Química Farmacêutica , Preparações de Ação Retardada/química , Portadores de Fármacos/química , Comportamento Alimentar , Inseticidas/química , Mariposas/fisiologia , Nanopartículas/química , Tamanho da Partícula , Porosidade , Dióxido de Silício/química , alfa-Ciclodextrinas/química
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