Biodegradable polymeric nanoparticles have the potential to significantly impact the agrochemical industry. It is imperative to study their behavior in plant systems to determine their effectiveness as sustainable agrochemical delivery systems. In this study we explore translocation of methoxyfenozide (MFZ) delivered by zein and lignin nanoparticles (ZNPs and LNPs) in soybean plants exposed to the particles through the roots under hydroponic conditions. ZNPs were synthesized by nanoprecipitation from zein with SDS as a surfactant, and LNPs were synthesized by emulsion evaporation from lignin-graft-poly(lactic-<i>co</i>-glycolic) acid. Both types of particles were loaded with MFZ, a non-systemic pesticide (6.2 % (w/w) in ZNPs, and 2.7 % (w/w) in LNPs). Dynamic light scattering confirmed that LNPs measured 106 nm in diameter, with a narrow size distribution and a zeta potential of – 42 mV. ZNPs measured 126.4 nm and had a zeta potential of 44.75 mV. Soybeans were grown hydroponically and were treated with 0.02, 0.2 or 2 mg/ml of LNPs or ZNPs at 28 days after germination. Plants were harvested after 6, 12, and 24 hours of continuous particle exposure to the root. Root, stem and leaves were collected and concentration of methoxyfenozide was quantified. Results indicated that both ZNPs and LNPs were effective at translocating MFZ from the hydroponic solution to the roots, and from the roots to the leaves of the plants relative to the control, free MFZ. LNPs were more effective than ZNPs at transporting MFZ from the hydroponic solution to the roots of the plants. For example, MFZ concentrations in the roots of plants treated with high concentration of LNPs were 184, 377, and 519 µg/g at 6, 12, and 24 hrs, relative to the much smaller 33, 46, and 143 µg/g delivered by the ZNPs even though the amount of MFZs available in the Hoagland solution spiked with ZNPs was higher than for LNPs at the same NP concentration, due to the higher loading of MFZ in the ZNPs. ZNPs translocated 16.2, 10.2 and 2.8 % of the available MFZ in the roots to the leaves (equivalent to 1.94, 3.68, and 5.08 µg) at low, medium, and high concentrations respectively. The LNPs translocation percentages were smaller 2.9, 3.4, 0.3 %, but led to similar amounts (0.23, 1.13, and 5 µg) in the leaves. In conclusion, ZNPs and LNPs were found suitable as sustainable delivery systems for MFZ and can be further developed to efficiently deliver other types of agrochemicals to plants.

Biodegradable zein and lignin nanoparticles as methoxyfenozide delivery systems in soybean plants

ACS Spring Meeting 2021

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