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Invasion and migration are major characteristics of malignant cancers. Inhibiting the migration of cancer cells, rather than simply removing the primary tumor, is essential for improving the survival rates. Two-dimensional (2D) materials have important application prospects in the field of biomedicine (especially in cancer therapy) due to their unique physicochemical properties. However, the basic biological effects of 2D material cobalt-based layered double hydroxides, especially its cytotoxicity and migration effects on a variety of cells, have not yet been revealed. Herein, the effect of 5 nm thick β-Co(OH)2 nanosheets (NSs) on cell viability and migration of normal cells and various cancer cells and their possible mechanisms were investigated. The cell viability assay and migration ability analysis found that β-Co(OH)2 NSs had a concentration-dependent and selective biological effects on normal cells HUVEC and cancer cells (4T1, SMMC-7721, and B16 cells). Compared with normal cells HUVEC, β-Co(OH)2 NSs showed remarkably stronger and differentiated cytotoxicity to cancer cells (4T1, SMMC-7721, and B16 cells), and it was found by wound healing and transwell assays that β-Co(OH)2 NSs also can inhibit cancer cell migration more sensitively which may be attributed to the down-regulation of the key epithelial-mesenchymal transition protein Snail2. This study on revealing the basic biological effects of cobalt-based nanosheets will not only promote the understanding of the interaction between nanosheets and cells, but will also help in developing cancer treatment platforms based on cobalt-based nanosheets to promote their applications in the inhibition of tumor migration and metastasis. [ABSTRACT FROM AUTHOR]

Exploiting cost-effective, highly efficient and stable alkaline electrocatalysts is a great challenge for the hydrogen evolution reaction (HER). Herein, NiMoO4 and CoFe layered double hydroxide (CoFe LDH) with poor crystallinity were successively deposited on Cu nanowire (Cu NW) grown on Cu foam by a two-step electrodeposition process, which was verified by XRD, Raman, ATR-FTIR, XPS, SEM, TEM and HRTEM characterizations. The HER performance measurement in 1.0 M KOH solution showed the optimal CoFe LDH-60 s/NiMoO4/Cu NW/Cu foam sample demonstrated prominent alkaline HER activity and long-term durability with an ultralow overpotential of 45 mV at −10 mA cm−2 and a Tafel slope of 94.0 mV dec−1, superior to the recently reported transition metal-based electrocatalysts. Further study clarified that the remarkable alkaline HER performance could be attributed to the strong synergistic effect between CoFe LDH-60 s and NiMoO4 in favor of water adsorption/activation and optimizing hydrogen adsorption, and providing plentiful exposed active sites as well as an enhanced electron transfer process offered by the unique 1D nanostructure with Cu nanowire as the core. This work can provide a guidance for designing a highly active and stable electrocatalyst for hydrogen production. [ABSTRACT FROM AUTHOR]