Naphthalene-based water-soluble fluorescent boronic acid isomers suitable for ratiometric and off-on sensing of saccharides at physiological pH
作者:Xingming Gao、Yanling Zhang、Binghe Wang
DOI:10.1039/b413376e
日期:——
Two water-soluble naphthalene-based fluorescent boronic acid isomers, 5-(dimethylamino)naphthalene-1-boronic acid (5-DMANBA, 1) and 4-(dimethylamino)naphthalene-1-boronic acid (4-DMANBA, 2), have been synthesized; their fluorescent properties upon binding with carbohydrates have been determined in aqueous phosphate buffer at pH 7.4. The difference in substitution pattern between 1 and 2 leads to significant differences in their fluorescence properties. For example, addition of fructose (50 mM) to a solution of 1 induced a 61% fluorescence intensity decrease at 513 nm and a 36-fold increase at 433 nm. This revealed that compound 1 is a potential sensor for ratiometric sensing of sugars. The pH titration curves of 1 in the absence and the presence of fructose (50 mM) showed a 93- and 200-fold fluorescence intensity increase at 433 nm, respectively, when pH was increased from 3 to 10. Compound 2, however, does not show ratiometric fluorescent intensity changes, but shows significant fluorescence intensity increase upon addition of a sugar (41-fold intensity increase with 50 mM fructose). The emission intensity of 2 increased by over 170-fold at 445 nm upon changing the pH from 2 to 11.
合成了两种水溶性萘基荧光硼酸异构体,即 5-(二甲基氨基)萘-1-硼酸(5-DMANBA,1)和 4-(二甲基氨基)萘-1-硼酸(4-DMANBA,2);在 pH 值为 7.4 的磷酸水缓冲液中测定了它们与碳水化合物结合时的荧光特性。1 和 2 之间取代模式的不同导致了它们荧光特性的显著差异。例如,在 1 的溶液中加入果糖(50 mM)后,513 纳米波长处的荧光强度降低了 61%,而 433 纳米波长处的荧光强度增加了 36 倍。这表明化合物 1 是一种潜在的糖类比率测量传感器。在没有果糖(50 mM)和有果糖(50 mM)的情况下,化合物 1 的 pH 滴定曲线显示,当 pH 值从 3 升至 10 时,在 433 nm 处的荧光强度分别增加了 93 倍和 200 倍。然而,化合物 2 并未显示出比率荧光强度变化,但在加入糖类后荧光强度显著增加(50 mM 果糖时强度增加 41 倍)。当 pH 值从 2 变为 11 时,化合物 2 在 445 纳米波长处的发射强度增加了 170 多倍。