Xiaoxia Li,Yuchen Luo,Shufang Zhou,Jiayi Wang,Futai Lu,Shuo Wang,Qiliang Deng
A sensor capable of sensing of water in various organic solvents ranging from water-soluble to water-miscible solvents is still a challenging task. In this research, a cyclic polymer fluorescence chemosensor (CPFC) has been developed for sensing of water by turn-on model in 9 organic solvents and turn-off model in DMA, where the broadest concentration range and the lowest detection limit was obtained for water in DMA (10 %–90 %) and dioxane (0.011 %), respectively. The sensing mechanism is explored by theory calculation and experimental investigation. The amphiphilic nature endows the polymer probe with great potential for measuring various contaminants from aqueous and nonaqueous mediums. Furthermore, the present search highlights the potential applications of cyclic polymer as fluorescence probes in the field of sensing.
Dehua Deng,Yuanqiang Hao,Ping Yang,Ning Xia,Wenxue Yu,Xiuhua Liu,Lin Liu
A general peptide substrate for the specific detection of proteases is linked with a quencher/fluorophore pair. However, labeling of the substrate with a quencher/fluorophore pair may increase the complexity for the synthesis of peptides and affect the approach of protease to the cleavage site. A peptide with a specific sequence has been shown to bind Cu2+ with high affinity. More intriguingly, Cu2+ exhibits a high inherent quenching ability towards the fluorophore by complexation with the sequence-specific peptide. Based on this fact, this work reports a general single-labeled peptide substrate for the detection of protease activity, screening of potential inhibitors and evaluation of cell apoptosis. The feasibility and applications of the method were demonstrated by assays of caspase-3 and β-secretase with a signal-on and a signal-off format, respectively.