Unravelling the role of nanoparticle morphology during uptake and transport in eggplants

Abstract

Understanding how the morphology of nanocarriers influences their interaction with plants is crucial for assessing their impact on plant health, human safety, and the environment, as well as exploring their potential applications in environmental remediation, plant sensing, and target delivery in plants. In this study, we designed and synthesized hydrophilic gold (Au) nanospheres and nanowires encapsulated in beta-cyclodextrin (β-CD) polymer as target nutrient carriers, and studied their translocation in eggplants. Electron microscopy and elemental analysis reveal that both nanocarrier types can penetrate the leaf surface, redistribute within leaf tissues, and undergo long-distance transport to stems and roots via vascular-associated pathways. Distinct morphology-dependent behaviour is observed: spherical nanocarriers largely retain their shape during transport, whereas wire-shaped nanocarriers frequently appear as fragmented segments within plant tissues. Given the low fraction of nanospheres in the initial suspension, this observation indicates in planta transformation rather than selective uptake of pre-existing fragments. Nanocarriers are predominantly localised in cell walls, intercellular spaces, and phloem-associated regions, with roots acting as terminal compartments for accumulation or exclusion of non-essential elements. Together, these results demonstrate that nanocarrier morphology influences both structural stability and spatial distribution in plants following foliar exposure. While the underlying molecular transport mechanisms remain to be fully resolved, this study provides experimentally supported insights into morphology-dependent nanocarrier behaviour and offers a framework for the future design of plant-compatible nanocarrier systems.