Zein Nanoparticles Uptake by Hydroponically Grown Soybean Plants

In the interest of developing and characterizing a polymeric nanoparticle pesticide delivery vehicle to soybeans, zein nanoparticle (ZNP) uptake by the roots and biodistribution to the leaves of soybean plants was measured. Zein was tagged with fluorescein isothiocyanate (FITC) and made into nanoparticles (135 ± 3 nm diameter. 0.202 ± 0.034 PDI and 81 ± 4 mV zeta-potential at pH 6) using an emulsion-diffusion method. After 10 days of hydroponic exposure, association between particles and roots of plants was found to vary based on bulk nanoparticle concentration. While 0.37 mg NP/mg dry weight were detected in roots immersed in 0.88 mg NP/mL nanoparticle suspension, 0.58 mg NP/mg dry weight associated with roots immersed in a high dose nanoparticle suspension of 1.75 mg NP/mL at 10 days. Nanoparticle root uptake followed second order kinetics. A small amount of increased fluorescence was detected in the hydroponically exposed plant's leaves, suggesting that either small amounts of particles or other fluorescent contaminants of zein were up taken by the roots and biodistributed within the plant. To the authors' knowledge, this is the first study in which the uptake and time-dependent association between polymeric nanoparticles and soybeans are quantified.