Phenanthroline bridged bis(β-cyclodextrin)s/ adamantane-carboxylic acid supramolecular complex as an efficient fluorescence sensor to Zn~(2+)

摘要

A water-soluble fluorescent Zn~(2+) sensor, 1,10-phenanthroline bridged bis(β-cyclodextrin) (1), was synthesized by “click chemistry”, and its fluorescence sensing behavior toward Zn~(2+) against various metal ions was investigated under physiological conditions. Significantly, 1 showed high selectivity and sensitivity toward Zn~(2+) with a limit of detection (LOD) down to 10~(-7) M. Moreover, the spectrophotometric studies demonstrated that after complexation with 1-admantanecarboxylic acid sodium salt (AdCA), the 1/AdCA complex gave much stronger binding affinity and lower LOD value toward Zn~(2+) through a cyclodextrin/ substrate/Zn~(2+) triple recognition mode. The fluorescence stopped-flow experiments also indicated that the association rate of complex 1/AdCA to Zn~(2+) was much faster than compound 1 to the same ion. Furthermore, the fluorescence intensity of 1 and 1/AdCA was greatly enhanced after binding Zn~(2+) in living cells, and thus 1 and complex 1/AdCA could be considered as a biosensor for Zn~(2+) at the cellular level.