ABSTRACT
We present a highly efficient structural color filtering approach for large-area application, using a nanoporous anodic alumina (NAA) film overlaid with an aluminum (Al) layer on top of an optically thick Al substrate. The NAA film, consisting of a self-assembled nanopore array in a hexagonal lattice, is equivalent to a quasi-homogeneous medium according to effective medium theory. The proposed structure enables strong absorption at resonance owing to the Fabry-Perot resonance supported by the metal-dielectric-metal configuration and the plasmonic effect mediated by the top nanoporous Al layer. The reflection colors can be readily tuned by altering the NAA thickness that is determined by anodization time, thereby allowing the flexible creation of complicated color images on a single platform. By fabricating three samples with different NAA thicknesses in a large area of 2 cm × 2 cm, it is confirmed that the proposed color filtering scheme exhibits highly enhanced color purity and high reflection efficiency of up to 73%, which is superior to that generated by previously reported NAA-based approaches. The presented strategy can pave the way for the efficient fabrication of large-area color filtering devices for various potential applications, including color display devices, imaging sensors, structural color printing, and photovoltaic cells.
ABSTRACT
OBJECTIVE: To investigate the effect of docosahexaenoic acid (DHA) on invasiveness of aflatoxin B1 (AFB1)-induced hepatocellular carcinoma cells in vitro. METHODS: HepG2.2.15 cells were exposed to different concentrations of AFB1 and DHA plus AFB1. The cell migration and invasion were assessed using wound-healing and Transwell assay, and flow cytometry was used to analyze the cell cycle changes. The ultrastructural changes of the cells were observed by transmission electron microscopy. RESULTS: Compared with the control group, the cells exposed to2 µmol/L AFB1 showed obviously enhanced migration and invasion with decreased cell ratio in G1/G1 phase and increased cell ratio in G2/M phase but no changes in S phase cells; transmission electron microscopy revealed the presence of multiple nucleoli and significantly increased mitochondria and Golgi apparatus in the exposed cells. Compared with AFB1-exposed cells, the cells treated with DHA and AFB1 showed decreased migration and invasion abilities, and the G1/G1 phase cells increased and G2/M phase cells decreased significantly; ultrastructurally, the cells contained single nucleoli with decreased mitochondria and vacuolization occurred in the cytoplasm. CONCLUSION: DHA can significantly inhibit AFB1-induced enhancement of cell migration and invasion in hepatocellular carcinoma cells in vitro.
