Effects of nanoTiO2 on tomato plants under different irradiances.

In this study, we investigated the physiological and photochemical influences of nanoTiO2 exposure on tomato plants (Lycopersicum esculentum Mill.). Tomato plants were exposed to 100 mg L-1 of nanoTiO2 for 90 days in a hydroponic system. Light irradiances of 135 and 550 µmolphoton m-2 s-1 were applied as environmental stressors that could affect uptake of nanoTiO2. To quantify nanoTiO2 accumulation in plant bodies and roots, we used transmission electron microscopy, energy-dispersive X-ray spectroscopy, inductively coupled plasma mass spectrometry, and X-ray powder diffraction. Phenotypic and physiological influences such as color change, growth rate, fruit productivity, pigment concentration, and enzyme activity (SOD, CAT, APX) were monitored. We observed numerous effects caused by high irradiance and nanoTiO2 exposure, such as rapid chlorophyll decrease, increased anthocyanin and carotenoid concentrations, high enzymatic activity, and an approximately eight-fold increase in fruit production. Moreover, light absorption in the nanoTiO2-treated tomato plants, as measured by a ultraviolet-visible light spectrometer, increased by a factor of approximately 19, likely due to natural pigments that worked as sensitizers, and this resulted in an ∼120% increase in photochemical activities on A, ФPSII, ФCO2, gsw, and E.

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

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 28Si+ 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 89Y+ to be monitored instead of 28Si+, 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.

Quantitative mapping of elements in basil leaves (Ocimum basilicum) based on cesium concentration and growth period using laser ablation ICP-MS.

Quantitative elemental mapping of metallic pollutants in sweet basil was studied by laser ablation (LA)-ICP-MS. For this, the sweet basil was cultivated in Hoagland nutrient solution spiked with 100 and 1000 ng mL-1 of Cs for 10-60 days. Then, the Cs distribution in collected leaves was determined by LA-ICP-MS using lab-synthesized standard pellets based on NIST 1573a tomato leaves. For comparison, S, Ca, and K were also simultaneously determined in this measurement with a13C+ signal from the leaves as an internal standard. The obtained calibration curves showed linear coefficient of determination (R2) of 0.991 for K and 0.999 for Cs. The concentration of Cs measured in the basil leaves increased with growth period and pollutant concentration, and accumulation followed the order of leaf margin, petiole, midrib, and veins. Although no visible symptom was detected, significant suppression of the growth rate was observed due to the presence of high-concentration Cs. The experimental model demonstrated herein showed potential for studying the influence of radioactive pollutants on plants and other organisms in the food chain.

Metal-doped inorganic nanoparticles for multiplex detection of biomarkers by a sandwich-type ICP-MS immunoassay.

Metal-doped inorganic nanoparticles were synthesized for the multiplex detection of biomarkers by a sandwich-type inductively coupled plasma mass spectrometry (ICP-MS) immunoassay. The synthesized Cs-doped multicore magnetic nanoparticles (MMNPs) were used not only for magnetic extraction of targets but also for ratiometric measurement in ICP-MS. In addition, three different metal/dye-doped silica nanoparticles (SNPs) were synthesized as probes for multiplex detection: Y/RhBITC (rhodamine B isothiocyanate)-doped SNPs for CRP (cardiovascular disease), Cd/RhBITC-doped SNPs for AFP (tumor), and Au/5(6)-XRITC (X-rhodamine-5-(and-6)-isothiocyanate)-doped SNPs for NSE (heart disease). For quantification, the doped metals of SNPs were measured by ICP-MS and then the signal ratio to Cs of MMNPs was plotted with respect to the concentration of targets by a ratiometry. Limits of detection (LOD) of 0.35 ng/mL to 77 ng mL(-1) and recoveries of 83%-125% were obtained for serum samples spiked with the biomarkers. Since no sample treatment was necessary prior to the extraction, the proposed method provided short analysis time and convenience for the multiplex determination of biomarkers, which will be valuable for clinical application.