A new method has been developed for the simple, fluorescence, turn-on detection of melamine, which utilizes DNA-templated silver nanoclusters (DNA-AgNCs) as a key component. In the sensor, melamine exhibits the dual functions: one is to enhance the fluorescence signal of DNA-AgNCs by its specific interaction with thymine residues in DNA template, and the other is to prevent Hg(II)-induced fluorescence quenching of DNA-AgNCs via its strong coordination with Hg(II). These consequently enable the sensitive and selective detection of melamine. By exploiting such novel features of melamine, we significantly increased the fluorescence response up to 360%, compared to the previous counterpart that relies on DNA-AgNCs only, and successfully determined melamine down to ca. 49 nM, a value that is 400 times lower than the safety level of 20 μM set by the US Food and Drug Administration. In addition, it was confirmed that the proposed approach works fine even in the real milk samples without any additional pre-treatment steps.
Astaxanthin (AST) exhibits potent antioxidant and anti-inflammatory activities but poor stability and biological efficacy, which limit its application in the food and medical industries. In the present study, a new strategy was proposed to enhance the biological activities of AST using fetal bovine serum-derived extracellular vesicles (EVs). Saponin-assisted incubation was used to load AST owing to its high encapsulation efficiency and loading capacity. AST-incorporated EVs (EV-ASTs) maintained their original EV morphology and showed high stability at 4 °C, 25 °C, and 37 °C over a 28-day period, which was attributed to the protective environment provided by the phospholipid bilayer membrane of the EVs. Additionally, the EV-ASTs exhibited excellent antioxidant and anti-inflammatory activities in HaCaT keratinocytes and RAW 264.7 macrophage cells, respectively; these were significantly higher than those of free AST. Furthermore, the mechanism associated with the enhanced biological activities of EV-ASTs was evaluated by analyzing the expression of genes involved in antioxidation and anti-inflammation, in parallel with cellular in vitro assays. These results provide insights into methods for improving the performance of hydrophobic drugs using nature-derived EVs and will contribute to the development of novel drug-delivery systems.
Aptamers In article 2300854 by Ki Soo Park and co-workers, an aptamer is obtained through in vitro selection targeted at small extracellular vesicles (sEVs), which exhibits exceptional binding affinity and specificity toward colorectal cancer (CRC) and its specific interaction with CRC sEVs further hinders the potential metastatic pathways of CRC progression, ultimately enabling non-invasive diagnostics and therapeutics of CRC.
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