Dispersible silica nanoparticles as carrier for enhanced bioactivity of chlorfenapyr

Abstract

Pesticides are being used in agriculture to control pests for better yield and production. However, due to evaporation, rain waste-out, photodegradation, hydrolysis and other factors, most pesticides are lost before they reach their targets.1) Extensive quantities of pesticides are used to compensate for the losses that lead to serious environmental pollution and human toxicity.1,2) An e ective way to solve these problems is nanotechnology. e increase in the surface to volume ratio and surface energy of nanopesticides facilitates the penetration and attachment of an e ective agent on the surface of plant. As a result, the e cacy could be signi cantly increased by the application of nanopesticides. 3,4) In some cases, controlled release technology can integrate into the advantages of nanopesticides. 5)erefore, it is believed that the production of nanopesticides will result in the use of smaller amount and fewer applications.3) Nanopesticides are environmentally friendly and provide new opportunities and wide application prospects for pesticide research. 3)Recently, the use of silica nanoparticles in pesticides has been attracting progressively more attention. 6,7) ey have been shown to be biocompatible and has potential as drug delivery vehicles for medical and veterinary treatments. Hollow and mesoporous silica nanoparticles have also been developed as carriers. [8][9][10] Experiments have demonstrated that they are e ective in the protection against UV degradation and controlled release dependently on the pore diameter and shell thickness. 8,9) However, the cost and industrialization of the carrier is usually the main impediment to the application of a nanopesticide. erefore, to accelerate the application of nanopesticides, inexpensive and commercialized carriers are required, and related studies are important.In research, s) both hydrophilic and hydrophobic silica nanoparticles have been reported to provide insecticide activity on their own. Dispersible silica nanoparticles have been inexpensively commercialized for years. ese nanoparticles were modi ed with an organic surfactant that made them dispersible into organic solvent, 11) enhancing the ability of a carrier to load a hydrophobic drug because the enormous surface-to-volume ratio will not be wasted by aggregation. In this paper, an e ective chlorfenapyr nanoformulation was prepared based on the above carrier.In a typical drug-loading process, 0.5 g of silica nanoparticles and 2.0 g of chlorfenapyr are added to acetone. e mixture is then stirred continuously by a magnetic follower at room temperature. A white turbid suspension appears, and the process continues for 30 min to ensure maximum drug loading. e white turbid suspension is centrifuged and washed with ethanol.e nal product is a white powder that has been dried in air at 40°C for 24 hr and ground in a ceramic pestle and mortar.The morphology and size of chlorfenapyr-loaded silica nanoparticles were measured with a JEM 2100 transmission electron microscopy (TEM) instrument. As shown in Fig. 1, the...

Safe nanotechnologies for increasing the effectiveness of environmentally friendly natural agrochemicals

“…A novel formulation based on silica NPs has also been proposed for improving the effectiveness and slowing the release of the pro‐insecticide chlorfenapyr, with promising results. Field tests showed that the insecticidal activity associated with silica NPs was at least twice that of chlorfenapyr, associated with microparticles or without particles, and the insecticide release was slowed down to over 20 weeks, providing high‐localized concentration over a long period …”

“…Field tests showed that the insecticidal activity associated with silica NPs was at least twice that of chlorfenapyr, associated with microparticles or without particles, and the insecticide release was slowed down to over 20 weeks, providing high-localized concentration over a long period. 13 Mesoporous silica nanoparticles (MSNs) are synthetic particles possessing well defined and tuneable pore sizes (2-50 nm), large pore volumes, high surface areas with easily-modifiable surface properties, chemical stability, resistance to microbial attack, tailorable nanostructures, biocompatibility, and aqueous degradability. 14,15 Moreover, MSN protect loaded active ingredients (AIs) against enzymatic degradation as no swelling or changes in porosity occur in response to external stimuli, such as pH and temperature.…”

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“…Las nanoemulsiones permiten mejorar la dispersión y absorción del ingrediente activo y hasta incrementan su toxicidad (Kookana et al, 2014;Chinnamuthu y Boopathi, 2009). Song et al, (2012) evaluaron el incremento de la toxicidad del clorfenapir (un insecticida y acaricida de uso agrícola) a través de la utilización de nanopartículas de sílice como portador. Tanto en sus estudios de laboratorio como de campo, observaron que la toxicidad para los insectos se duplicó con respecto a la formulación a nivel micro.…”

“…Nanoemulsions allow to improve dispersion and absorption of the active ingredient and even to increase its toxicity (Kookana et al, 2014;Chinnamuthu and Boopathi, 2009). Song et al, (2012) evaluated the increase of toxicity of chlorfenapyr (an insecticide and acaricide of agricultural use) throungh thw utilization of nanoparticles of silica as carrier. Both in their laboratory and field studies they observed that toxicity for insects doubled in respect to micro formulation.…”

Preparation of nanoscale Bacillus thuringiensis chitinases using silica nanoparticles for nematicide delivery

“…Recently, numerous studies have focused on silica nanoparticles (SNPs) use in pesticides [10]. They have been shown to be high stability, chemical versatility, biocompatibility, and low cost have potential as nano-pesticide delivery system for agro-biotechnological applications [11][12][13].…”