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Enrichment of selenium (Se) by seaweed is of great significance for mariculture. In this study, the green alga Ulva fasciata was cultured with a selenite (NaSeO) concentration from 0 to 1,250 mg L. Se accumulation in the algal biomass was linearly related to NaSeO concentration in the culture medium. Lower Se concentrations (≤750 mg L) increased the activities of guaiacol peroxidase (GPX), catalase (CAT), peroxidase (POD) and superoxide dismutase (SOD) and the content of photosynthetic pigments, and as well induced lipid peroxidation (LPO) and intracellular reactive oxygen species (ROS) levels. Meanwhile, the cell growth rate and concentrations of organic Se increased. In contrast, these changes were the opposite in U. fasciata exposed to Se concentrations higher than 750 mg L. In all cases, Se- Ulva was able to remove inorganic nutrients effectively. Therefore, U. fasciata is tolerant to Se, and Se- Ulva has potential as a source of antioxidative food and an effective control of eutrophication. [ABSTRACT FROM AUTHOR]

Gracilaria is the second most productive genus of mariculture seaweeds after Laminaria in China. It is important to increase its economic value. The purpose of this study was to document the accumulation and biotransformation of selenium in Gracilaria lemaneiformis. The seaweed was cultured for 12 days in medium containing from 0 to 2000 mg L−1 selenite. At concentrations lower than 750 mg L−1, seaweed growth was promoted and the amount of chlorophyll a decreased. The organic Se content in the seaweed was over 80% in all groups and was as much as 400 μg g−1 of dry weight. Se enrichment induced a decrease in the activities of superoxide dismutase in the seaweed cells. These results suggest that G. lemaneiformis is tolerant to Se and prevents phytotoxicity by altering various metabolic processes. Furthermore, this seaweed exhibits great potential to transform inorganic Se into the organic form and therefore could be a safe candidate for the production of Se-enriched functional food. [ABSTRACT FROM AUTHOR]

Highlights: 2D Sn nanosheets (SnNSs) were prepared through the combination of cryogenic exfoliation and liquid-phase exfoliation. The functionalized 2D SnNSs have good stability, superior biocompatibility, high photothermal conversion efficiency, and multimode imaging capability.Stanene (Sn)-based materials have been extensively applied in industrial production and daily life, but their potential biomedical application remains largely unexplored, which is due to the absence of the appropriate and effective methods for fabricating Sn-based biomaterials. Herein, we explored a new approach combining cryogenic exfoliation and liquid-phase exfoliation to successfully manufacture two-dimensional (2D) Sn nanosheets (SnNSs). The obtained SnNSs exhibited a typical sheet-like structure with an average size of ~ 100 nm and a thickness of ~ 5.1 nm. After PEGylation, the resulting PEGylated SnNSs (SnNSs@PEG) exhibited good stability, superior biocompatibility, and excellent photothermal performance, which could serve as robust photothermal agents for multi-modal imaging (fluorescence/photoacoustic/photothermal imaging)-guided photothermal elimination of cancer. Furthermore, we also used first-principles density functional theory calculations to investigate the photothermal mechanism of SnNSs, revealing that the free electrons in upper and lower layers of SnNSs contribute to the conversion of the photo to thermal. This work not only introduces a new approach to fabricate 2D SnNSs but also establishes the SnNSs-based nanomedicines for photonic cancer theranostics. This new type of SnNSs with great potential in the field of nanomedicines may spur a wave of developing Sn-based biological materials to benefit biomedical applications. [ABSTRACT FROM AUTHOR]

Ruthenium-based complexes have emerged as promising antitumor and antimetastatic agents during the past decades. However, the limited understanding of the antimetastatic mechanisms of these agents is a roadblock to their clinical application. Herein, we reported that, RuPOP, a ruthenium polypyridyl complex with potent antitumor activity, was able to effectively inhibit growth and metastasis of MDA-MB-231 cells and synergistically enhance TRAIL-induced apoptosis. The selective intracellular uptake and cytotoxic effect of RuPOP was found associated with transferring receptor (TfR)-mediated endocytosis. Further investigation on intracellular mechanisms reveled that RuPOP notably suppressed FAK-mediated ERK and Akt activation. Pretreatment of cells with ERK inhibitor (U0126) and PI3K inhibitor (LY294002) significantly potentiated the inhibitory effect of RuPOP on cell growth, migration and invasion. Moreover, the alternation in the expression levels of metastatic regulatory proteins, including uPA, MMP-2/-9, and inhibition of VEGF secretion were also observed after RuPOP treatment. These results demonstrate the inhibitory effect of RuPOP on the growth and metastasis of cancer cells and the enhancement of TRAIL-induced apoptosis though suppression of FAK-mediated signaling. Furthermore, RuPOP exhibits the potential to be developed as a metal-based antimetastatic agent and chemosensitizer of TRAIL for the treatment of human metastatic cancers. [ABSTRACT FROM AUTHOR]