Impact of Type of Lignin, Alkaline and Lignosulfonate, on Release and Soil Adsorption of Methoxyfenozide Delivered with Lignin-graft-PLGA Nanoparticle
Abstract
The intensive application of pesticides in agriculture suffers from poor dispersion, runoff, and rapid degradation, which has raised serious environmental and economic concerns. This study investigates the use of lignin-based nanoparticles (LNPs) as sustainable carriers for the controlled delivery of methoxyfenozide (MFZ), enhancing delivery efficiency and reducing environmental impact. Core–shell nanoparticles were synthesized using alkaline lignin (ALN) and lignosulfonate (SLN), both grafted with poly(lactic-co-glycolic acid) (PLGA) biopolymers. Both systems achieved 3 wt % MFZ loading with entrapment efficiencies exceeding 50% (52.7% for SLNPs and 56.3% for ALNPs), yielding spherical, negatively charged particles of different sizes: SLNPs (250.3 ± 9.2 nm) and ALNPs (165 ± 0.4 nm). Release studies evaluated under two pH and temperature conditions demonstrated that the lignin type used influenced NP size and active component release, correlating with differences in the functional group composition (sulfonic, carboxylic, and phenolic groups) of ALN and SLN. Soil adsorption experiments showed enhanced MFZ adhesion to soil when delivered via LNPs (80% MFZ adsorbed compared to 40% when delivered in free form), potentially reducing runoff and overapplication. Overall, these findings identify key governing parameters, providing a mechanistic basis for engineering lignin-based nanoparticles with customizable release profiles and soil adsorption as pesticide delivery systems.