Visual tracking of engineered nanomaterials-facilitated pesticide absorption and translocation in plants

Visualizing the movement of pesticides carried by engineered nanoparticles within plants is vital for understanding their behavior. This research presents a novel visualization technique for intuitively monitoring the manner of nanocarriers delivering pesticides to plants. Using in situ surface-enhanced Raman spectroscopy (SERS) imaging analysis, the performance of engineered nanomaterials (ENMs) as carriers to enhance the transdermal transport of pesticides on plant leaves was successfully evaluated. The hydrophilic nature of polyvinylpyrrolidone (PVP) was observed to facilitate the stable adsorption of ENMs such as gold nanoparticles (Au NPs) on the hydrophilic molecules or functional groups on the leaf surface. Additionally, the gold-sulfur bond between Au NPs and dimethoate enhanced the adhesion and absorption of the pesticide by the plant. Notably, the small-sized Au NPs-dimethoate complex exhibited greater penetration depth and velocity compared to its larger counterpart. The uneven distribution of the Au NPs-dimethoate complex across the leaf cross-section was influenced by the physical structure. Overall, the penetrating capacity of Au NPs on plant leaves played a crucial role in enhancing the effective delivery of dimethoate, increasing both the adsorption capacity and penetration rate. This advancement results in a reduction in the quantity of pesticide applied, fundamentally mitigating the environmental pollution and aligning with environmental conservation objectives.