(608b) Toward Precision Agrochemical Delivery: A Botanokinetic Framework for Organic Nanocarrier Evaluation in Plants

Current agrochemical application methods are notoriously inefficient, with less than 0.1% of applied active ingredients reaching their intended physiological targets in plants. This inefficiency is particularly problematic given the growing pressures of global food demand, climate-induced stressors, and increasing pathogen resistance. Nanotechnology offers a promising route to enhance the systemic delivery of agrochemicals, yet the mechanistic understanding of how nanocarriers (NCs) translocate through plant tissues remains limited. To address this gap, we are developing a botanokinetic framework in Solanum lycopersicum (tomato), a model dicot, to systematically evaluate how NC characteristics such as surface charge, particle size, and surface biomolecule composition affect uptake and distribution in planta as a function of time.

Using Flash Nanoprecipitation (FNP), we produced NCs with a hydrophobic gadolinium-based core—chosen for its traceability via ICP-MS—and amphiphilic stabilizers forming the tunable shell. Two surface chemistries, lecithin and poly(styrene)-block-poly(acrylic acid) (PS-b-PAA), were selected. NCs were applied adaxially to the second true petiole of 4-week-old tomato plants, and tissues were harvested at five timepoints post-dosing (0.5, 1, 3, 7, and 30 days). Following drying and microwave digestion of tissue sections, gadolinium levels were quantified via ICP-MS to generate spatial and temporal translocation profiles.

Our initial findings indicate that lecithin-based NCs exhibited rapid uptake and complete systemic distribution within 12 hours of foliar application. In contrast, PS-b-PAA-based NCs displayed prolonged mobility, continuing to redistribute within the plant over 30 days. Particle size and zeta potential measurements confirmed differences in charge and hydrodynamic diameter between the two formulations. These data suggest that the identity of the surface biomolecule—not just electrostatic or size considerations—plays a critical role in governing NC internalization and translocation. This finding underscores the need to consider surface chemistry as a key design parameter for plant-targeted nanocarriers.

This research provides one of the first kinetic models for organic NC transport in a crop species. It lays the foundation for a predictive framework to design nanocarrier-based delivery systems rationally. By linking physicochemical properties to in planta behavior, we move closer to developing targeted, efficient, and sustainable agrochemical delivery platforms for the next generation of crop management strategies