香豆素-半花菁-苯硼酸对唾液酸的识别与光学传感

Recognition and optical sensing of sialic acid via coumarin-hemicyanine-phenylboronic acid

以共轭连接的香豆素和半花菁为信号报告基团,以苯硼酸为识别基团,设计合成了一种对唾液酸具有选择性识别的比色型荧光传感分子,命名为CHB,并采用吸收和荧光光谱方法研究其对唾液酸(N-乙酰神经氨酸)及其他糖类分子(如葡萄糖、蔗糖和麦芽三糖等)的响应.结果表明,CHB仅对N-乙酰神经氨酸表现出显著的吸收和荧光光谱响应,并通过高分辨质谱研究证实二者以1∶1计量比通过共价作用结合形成复合物.N-乙酰神经氨酸与苯硼酸的共价作用和静电作用共同影响了香豆素-半花菁共轭体系的分子内电荷转移,从而引起显著的溶液颜色变化和高选择性的光谱响应,因此CHB可用于N-乙酰神经氨酸的可视化检测.

A colorimetric and fluorescent chemosensor CHB was designed and synthesized,using a coumarin-hemicyanine conjugate skeleton as the signal reporter and phenylboronic acid as the receptor.The interactions of CHB with N-acetylneuraminic acid(Neu5 Ac)and other saccharides such as glucose,sucrose,maltotriose were investigated using absorption and fluorescence spectroscopy.Significant absorption and fluorescence spectral responses and obvious color changes were only observed in the presence of Neu5 Ac,whereas the other saccharides produced weak spectral changes and exerted practically no interference.And it was proved with high resolution mass spectroscopy(HRMS)that CHB and Neu5 Ac formed a complex via covalent bonding at a ratio of 1∶1.It was suggested that Neu5 Ac modulated the intramolecular charge transfer of coumarin-hemicyanine conjugate system in CHB together with the covalent interaction and electrostatic interaction,allowing a highly selective spectral sensing of Neu5 Ac,with the potential of visual recognition.