Novel optical materials are crucial for environmental monitoring. Metal nanoclusters ( metal NCs) , typically consisting of several to tens of metal atoms, have attracted more and more attention for recent years. Due to their ultrasmall size, strong fluorescence, low toxicity, excellent stability and unique core-shell structure, metal NCs have been considered as promising optical materials for the construction of excellent fluorescent sensors. In this review, we mainly focus on the recent progress in their applications in environmental monitoring, including the detection of pH, heavy metal ions, inorganic anions and nitroaromatic explosives.

Objective:To investigate the mechanism by which Melittin-K1 reverses multidrug resistance of BEL-7402/5-FU cells.Methods:CCK-8 assay was used to evaluate the effect of Melittin-K1 on the growth of BEL-7402/5-FU cells and to explore whether Melittin-K1 could reverse the drug resistance of BEL-7402/5-FU cells. The expression of MDR1 mRNA level was detected by real-time fluorescence quantitative PCR assay. The flow cytometry was used to measure the expression of P-glycoprotein (P-gp) on the cell membrane surface and the accumulation of rhodamine-123 in cells.Results:Melittin-K1 significantly inhibited the growth of BEL-7402/5-FU cells in vitro in a time and dose-dependent manner. Melittin-K1 suppressed the level of MDR1 mRNA and inhibited the surface expression and function of P-gp in BEL-7402/5-FU cells. Conclusions:Melittin-K1, a novel peptide, exhibited the activity of reversing multidrug resistance of liver cancer cells.