An enzyme-responsive core-double shell structured nano pesticide delivery system for improving the UV stability of emamectin benzoate (EB)

Currently, the inefficient application of pesticides results in substantial cost wastage and severe environmental contamination. The rapid advancement of nanomaterials and controlled/sustained-release technologies offer a promising guidance for reducing pesticide usage and enhancing pesticide bioavailability. In this study, naturally derived Zein and β-cyclodextrin (β-CD) polysaccharide were employed for synergistic encapsulation of emamectin benzoate (EB) pesticide molecule. Specifically, amino-functionalized Zein (AM-Zein) was effectively self-assembled onto β-cyclodextrin (β-CD) through electrostatic and hydrogen bonding interactions, with simultaneous encapsulation of EB through hydrophobic interactions, thereby establishing a core-double shell structured nano pesticide delivery system (EB@β-CD/AM-Zein). Compared to the single AM-Zein and β-CD, the double shell structured β-CD/AM-Zein demonstrated a notably higher encapsulation efficiency for EB. Importantly, the half-life period (t0.5) under UV irradiation of EB for EB@β-CD/AM-Zein was almost three times longer than that of EB alone. Enzyme-responsive controlled-release tests for EB@β-CD/AM-Zein revealed that the majority of EB was encapsulated within the inner β-CD layer. Specifically, the degradation of β-CD by α-amylase enabled the intelligent responsive release feature of EB. Moreover, the insecticidal activity of EB@β-CD/AM-Zein remained stable. This research offers valuable insights for developing effective and environmentally safe nano pesticide systems.