Bideposited silver nanocolloid arrays with strong plasmon-induced birefringence for SERS application

Silver nano-rod, nano-zigzag, nano-saw, and nano-particle arrays are fabricated with glancing angle bideposition. The structure-dependent anisotropic optical properties of those bideposited nanostructured arrays are measured and investigated. The equivalent birefringence values of nano-rod and nano-zigzag arrays are much larger than crystals found in nature and liquid crystal used in display products. The fact that induced localized plasmon-magnetic field between nanorods dominates the strong phase retardation between p-polarized and s-polarized transmitted wave. For the nano-saw, the strong localized electric field induced between the saw teeth leads to strong SERS signals. Although the bideposited nanoparticles own weak morphological anisotropy, strong optical phase retardation is still detected at wavelengths near 400 nm.

The Influence of Copper and Silver Nanocolloids on the Quality of Pressed Spring Rapeseed Oil

The aim of this study was to evaluate the quality of virgin oil pressed from spring rape seeds cultivated with the use of colloidal nanosilver and nanocopper solutions for processing seeds and as foliar fertilizer. The results show that the use of nanometals for seed processing and foliar fertilization increased the content of carotenoid pigments in the oil. The pigment concentration was higher compared to oil pressed from control seeds. The application of nanocolloids onto the seeds and subsequently on the growing plants contributed to the increase of the oxidative stability of oils. Both the acid number (AN) and peroxide number (PN) values were higher in the studied oils as compared to the control, but did not exceed the required allowable levels. Increased content of silver ions and slightly increased copper content was observed in the pressed oil. An infrared spectral analysis (Fourier-Transformed Infra-Red) conducted in combination with chemometrics allowed the classification of the studied oils in terms of their chemical composition. The analysis revealed the presence of bands characteristic of Cu-O-H vibrations after soaking the seeds and spraying the plants with copper nanocolloid, and of C-O-Ag after fertilization with silver nanocolloid.

Commercial Metal-Based Nanocolloids - Evaluation of Cytotoxicity

The purpose of the study was to determine the cytotoxicity of commercial silver, gold, and copper nanocolloids towards two established cell lines (NIH/3T3 and GMK) and primary chick embryo cell culture (CECC), using routine colorimetric assays: MTT, NRU, and LDH, which enable a preliminary evaluation of the mechanism of cytotoxic effect of the tested substances. The MTT assay evaluates the activity of mitochondria, NRU assay reveals the damage to lysosomes, while LDH assay shows injuries to the cytoplasmic membrane. The NRU assay proved to be non-applicable to the tested nanocolloids, most probably due to the interaction of nanoparticles with neutral red dye, which affected the colorimetric reaction. The MTT assay was more sensitive than LDH because the intercellular effect of a substance occurs before permanent damage to the cytoplasmic membrane. Silver nanocolloid was distinguished by the highest cytotoxicity, irrespective of the applied cell model, although the other two metals showed some cytotoxic effects as well, with gold nanocolloid being more toxic than copper one. Although the primary chick embryo cell culture, as a model reflecting more faithfully the conditions in a living organism than continuous cell lines, was undistinguished by elevated tolerance to the most toxic silver nanocolloid, it showed the tendency to recovery from the growth suppression with longer exposure after the application of less toxic gold and copper nanocolloids.