Assessing the Fate of Superparamagnetic Iron Oxide Nanoparticles Carrying Usnic Acid as Chemical Cargo on the Soil Microbial Community

Abstract

In the present study we evaluate the effect of superparamagnetic iron oxide nanoparticles (SPIONs) carrying usnic acid (UA) as chemical cargo on the soil microbial community in a dystrophic red latosol (oxysol). Herein, 500 ppm UA or SPIONs-framework carrying UA were diluted in sterile ultrapure deionized water and applied by hand sprayer on the top of the soil. The experiment was conducted in a growth chamber at 25 °C, with a relative humidity of 80% and a 16 h/8 h light–dark cycle (600 lx light intensity) for 30 days. Sterile ultrapure deionized water was used as the negative control; uncapped and oleic acid (OA) capped SPIONs were also tested to assess their potential effects. Magnetic nanostructures were synthesized by a coprecipitation method and characterized by scanning and transmission electron microscopy (SEM and TEM), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), zeta potential, hydrodynamic diameter, magnetic measurements, and release kinetics of chemical cargo. Uncapped and OA-capped SPIONs did not significantly affect soil microbial community. Our results showed an impairment in the soil microbial community exposed to free UA, leading to a general decrease in negative effects on soil-based parameters when bioactive was loaded into the nanoscale magnetic carrier. Besides, compared to control, the free UA caused a significant decrease in microbial biomass C (39%), on the activity of acid protease (59%), and acid phosphatase (23%) enzymes, respectively. Free UA also reduced eukaryotic 18S rRNA gene abundance, suggesting a major impact on fungi. Our findings indicate that SPIONs as bioherbicide nanocarriers can reduce the negative impacts on soil. Therefore, nanoenabled biocides may improve agricultural productivity, which is important for food security due to the need of increasing food production.

Nano-Iron Oxide (Fe3O4) Mitigates the Effects of Microplastics on a Ryegrass Soil–Microbe–Plant System

“…In terms of nanoenabled plant protection, the results showed a positive effect of nano-Fe 3 O 4 from plant belowground soils. Moreover, Fe-based NP products can be applied by spraying them on the top of the soil as nanocarriers of biopesticides, which can weaken the toxicity of pesticides to soil microbiota . NPs can also be applied as a foliar spray to enhance crop nutritional quality.…”

“…Moreover, Fe-based NP products can be applied by spraying them on the top of the soil as nanocarriers of biopesticides, which can weaken the toxicity of pesticides to soil microbiota. 77 NPs can also be applied as a foliar spray to enhance crop nutritional quality. These findings reflect the potential of NPs as an ecofriendly, high-efficiency, and sustainable plant protection strategy.…”

New Advances in Nano-Enabled Weed Management Using Poly(Epsilon-Caprolactone)-Based Nanoherbicides: A Review

“…Numerous studies have been conducted for the development of nanoherbicides due to their superior effectiveness and environmentally friendly advantages [39][40][41][42]. Hence, nanomaterials for assembling nanoherbicides can be categorized based on their purpose: they can be put together in a way to make water-insoluble active components more soluble, to gradually slow down how quickly they release their active ingredients, to complete targeted distribution, and to promote chemical permanence [43].…”