Nanoparticles Based on Modified Starch for Enhanced Herbicides’ Penetration and Efficiency

Nowadays, herbicides are widely used for effectively growing agricultural produce by spraying it in a high concentration over the entire plant. As a result, part of the herbicide penetrate and contaminate the soil, and consequently the contamination of ground water is of high potential.

This study is attempting to minimize these problems using a herbicide controlled release system that is based on the electrostatically formation of nanoparticles comprised of positively charged quaternized (quaternary amine) starch (Q-starch) as a carrier, and negatively charged herbicide. The use of these nanoparticles can improve both, the herbicide infiltration into the plant, and the movement of the herbicide inside the xylem and phloem. In addition, the controlled release of the herbicide might allow us to use lower concentrations, which can prevent the pollution of the soil and ground water.

In the study, Q-starch was synthesized and identified by FTIR, H-NMR, and elementary analysis, and the nanoparticles were created and characterized by Nanosight and Zeta-potential for their size and charge respectively. Subsequently, the parameters controlling the nanoparticles’ size and rate of herbicide release were evaluated. After establishing the optimal nanoparticles’ formation protocol, that allow the formation of nanoparticles at the proper size and concentration, they were tested on tobacco plants. In order to test the nanoparticles entrance pathway into the plant, the carrier was labelled fluorescently by 5-(4,6-Dichlorotriazinyl) Aminofluorescein. After exposure to a precise amount of nanoparticles, the tobacco leaf was examined under a confocal microscope and the nanoparticles entrance was evaluated.

Our results demonstrated that the nanoparticles infiltrate into the plant, act more effectively than the herbicide alone. Moreover, the herbicide apparently passes from one leaf to other parts of the plant. As a result, it might be possible to use the herbicide in a lower concentration and to minimize its harm to the environment.