New approach for mapping and physiological test of silica nanoparticles accumulated in sweet basil (Ocimum basilicum) by LA-ICP-MS

Abstract Behavior of silica nanoparticles (SiNPs) in sweet basil was studied using laser ablation inductively coupled plasma mass spectroscopy (LA-ICP-MS) as an in situ monitoring tool. Although the use of SiNP for environmental applications is interesting, detailed studies in plants for distributional mapping and quantitative determination have been difficult because the detection of 28 Si + suffers from severe molecular interference and high background in ICP-MS. In this work, yttrium/fluorescein-isothiocyanate-doped silica nanoparticles (Y/FITC-doped SiNPs) synthesized in our lab were used to substitute for undoped SiNP, allowing the doped 89 Y + to be monitored instead of 28 Si + , while retaining the same surface properties. Based on this model, the physiological influence was studied by nourishing them with a nutrient solution spiked with the synthesized SiNPs and a co-pollutant, Cs ion. Mapping images obtained by LA-ICP-MS showed distinct accumulation patterns associated with exposure. For example, Cs was distributed widely over the leaves, whereas SiNPs were concentrated in specific regions such as main veins, leaf margins, and tips. Furthermore, the possible effect of SiNP and Cs on the photochemical reaction was confirmed through monitoring the change of the concentration of chlorophyll and carotenoid and the superoxide dismutase (SOD) activity.