Polysaccharide nanocarriers as sustainable material systems for agrochemical delivery: Design strategies, recent advances, and future directions

Polysaccharides are naturally abundant, sustainable biopolymers that are non-toxic, biodegradable and biocompatible. The molecular architecture and supramolecular organization of polysaccharides including glycosidic linkages, branching, crystallinity, charge distribution, functional groups, and block copolymer sequences govern their self-assembly, gelation, swelling, and responsiveness. These characteristics make polysaccharides highly beneficial for synthesizing nanocarriers with tailored loading capacities, triggered and controlled release, and plant compatibility, which are essential for efficient delivery of agrochemicals. Recent research suggests that polysaccharide nanoparticles can serve as seed coverings, foliar delivery agents, soil additives, and controlled-release systems for fertilizers and pesticides, thereby enhancing agrochemical efficacy and reducing environmental impact. This review critically assesses the synthesis methodologies, material design concepts, and plant absorption mechanisms of polysaccharide nanocarriers, highlighting the impact of molecular characteristics on nanoparticle stability, mobility, and translocation within plants. These insights enhance understanding of key challenges, such as large-scale production, reproducibility, and limited field studies, while highlighting emerging opportunities for developing more effective and scalable solutions toward green and sustainable agriculture.