Precise and High-Throughput Delivery of Micronutrients in Plants Enabled by Pollen-inspired Spiny and Biodegradable Microcapsules.

Decarbonizing food production and mitigating agriculture's environmental impact require new technologies for precise delivery of fertilizers and pesticides to plants. The cuticle, a waxy barrier that protects the surface of leaves, causes 60-90% runoff of fertilizers and pesticides, leading to the wastage of intensive resources, soil depletion, and water bodies pollution. Solutions to mitigate runoff include adding chemicals (e.g., surfactants) to decrease surface tension and enhance cuticles' permeability but have low efficacy. In this study, we use vapor-induced synergistic differentiation (VISDi) to nanomanufacture echinate pollen-like, high payload content (∼50 wt%) microcapsules decorated with robust spines that mechanically disrupt the cuticle and adhere to the leaf. VISDi induces a core-shell structure in the spines, enabling the release of agrochemicals from the microparticles' body into the leaf. As proof of concept, we demonstrated precise and high throughput delivery of iron fertilizer in Fe-deficient spinach plants. Spray of spiny microparticles improved leaf adhesion by mechanical interlocking, reduced wash-off by a ∼12.5 fold, and enhanced chlorophyll content by ∼7.3 times compared to the application of spherical counterparts. Together, these results show that spiny microparticles can mitigate agricultural runoff and provide a high throughput tool for precise plant drug delivery. This article is protected by copyright. All rights reserved.