Leaf elemental imaging using a custom 3D-Printed slicing device following quantum dot exposure

Owing to the growing use of nanomaterials in botany and agriculture, nanoparticles entered into soil and water bodies may be taken up by plants and disturb their nutrient homeostasis. Here we developed a laboratory-made 3D-printed multi-well slicing device that cuts an intact leaf into a uniform grid and permits in-well acid digestion directly in the array, followed by ICP-MS, providing a low-cost approach to spatial elemental imaging for leaves. Pumpkin seedlings were exposed hydroponically for 8 days to 20 or 100 pmol mL^-1 CdSe/ZnS-GSH. Neither dose caused significant root damage, as indicated by Evans Blue uptake, malondialdehyde content, and Schiff's reagent staining, whereas total leaf fresh weight increased by 16.7 ± 9.1% and 19.9 ± 5.9%, respectively. Bulk leaf analysis showed that most nutrients (Mg, Ca, B, Mn, Na, and Fe) remained unchanged; only Zn was elevated 3.75- and 5.68-fold, Cu was reduced by approximately 21.5% at the high dose, Se increased dose-dependently while Cd did not. Spatial imaging further revealed that Se and Zn redistributed along leaf veins, with Se migrating more readily than Cd. This device offers a simple techniques to quantitatively imaging for leaf elements, and the effects of quantum dots on the spatial homeostasis of plant nutrient elements also offers a new perspective on plant responses.