In vivo biosynthesis and spatial distribution of Ag nanoparticles in maize (Zea mays L.)

Biosynthesis of Ag nanoparticles and two-dimensional element distribution in Arabidopsis

Metallic nanoparticles can be synthesised in living plants, which provide a friendly approach. In this work, the authors aimed to study the synthesis of silver nanoparticles (AgNPs) in Arabidopsis and the two-dimensional (2D) distribution of Ag and other elements (Ca, P, S, Mg, and CI) in the Arabidopsis plant tissues. The concentrations of Ag in the plant tissues were determined by inductively coupled plasma-atomic emission spectrometer, showing that the majority of Ag was retained in the roots. Transmission electron micrographs showed the morphology of AgNPs and the location in plant cells. The distributions of Cl and Ag were consistent in plant tissues by 2D proton-induced X-ray emission. In conclusion, this is the first report of the AgNP synthesis in Arabidopsis living plants and its 2D distribution of important elements, which provide a new clue for further research.

Investigation on the 2D-Distribution of Metallic Elements after Hair Dyeing

Long-term use of hair dyes has potential effects on metal content in hair. However, little research dissects the specific distribution and composition variations of the metal after dyeing. In this study, we investigated the morphological change and metallic elements content variation after dyeing. The results showed that the concentration of essential metal elements decreased, among which the Ca, K, and Na decreased sharply even above 50%. As for the heavy metal, the most significant observation is that Pb increased almost by five times after dyeing. Besides, it revealed, using scanning electron microscope coupled with energy-dispersive X-ray spectroscopy (SEM-EDS), that Pb concentrated at the outer layer of the hair. In addition, two-dimensional proton-induced X-ray emission (2D-PIXE) was applied to analyze the distribution of metallic elements along the longitudinal and cross section of the hair. The results showed that Ca and Zn distributed evenly in the hair along the longitudinal and cross section. It is the first time that 2D-PIXE is applied to analyze the metallic distribution in the hair. This method exhibits high sensitivity and can be widely used in the environmental and medical field to analyze the distribution of metallic elements.

Nanoparticles: biosynthesis, translocation and role in plant metabolism

Nanotechnology is an emerging field of science that applies particles between 1 and 100 nm in size for a range of practical uses. Nano-technological discoveries have opened novel applications in biotechnology and agriculture. Many reactions involving nanoparticles (NPs) are more efficient compared to those of their respective bulk materials. NPs obtained from plant material, denoted as biogenic or phytosynthesised NPs, are preferred over chemically synthesised NPs due to their low toxicity, rapid reactions and cost-effective production. NPs impart both positive and negative impacts on plant growth and development. NPs exhibit their unique actions as a function of their size, reactivity, surface area and concentration. An insight into NP biosynthesis and translocation within the plant system will shed some light on the roles and mechanisms of NP-mediated regulation of plant metabolism. This review is a step towards that goal.