基于FRET的双发射荧光探针的传感机理及分子设计

Sensing Mechanism and Molecular Design of FRET based Dual-emission Fluorescent Probe

氢过硫化物(R-SSH)是调节哺乳动物生理过程中重要的反应活性硫物种.采用密度泛函理论(DFT)和含时密度泛函理论(TD-DFT)方法,研究了香豆素和氧杂蒽为给受体的R-SSH探针的电子结构及光物理性质,并对其响应机制进行了理论分析.计算结果表明,氧化后电子吸收光谱的明显蓝移源于分子内局域激发本质发生根本改变.由于电荷转移跃迁特征增强导致长波发射带消失,使荧光共振能量转移由开到关,实现了氢过硫化物的可逆比率荧光检测.设计的PX1和PX2满足荧光共振能量转移和比率荧光探针条件,可作为氢过硫化荧光探针使用.

Hydrogen persulfide(R-SSH)was an important reactive sulfur species that regulates the physiological processes of mammals.Density functional theory(DFT)and the time-dependent density functional theory(TD-DFT)method was used to investigate electronic structure and photophysical properties of R-SSH probe contained coumarin donor and xanthene acceptor.Response mechanism of the probe molecule were analyzed by theoretical calculations.The results indicated that the obvious blue shift of the electron absorption spectrum after oxidation originates from the fundamental change of the intramolecular local excitation nature.Due to the enhancement of the charge transfer transition feature,the long-wave emission band disappears,and the fluorescence resonance energy transfer(FRET)is turned from"on"to"off",realizing the reversible ratiometric detection of hydrogen persulfide.The designed PX1 and PX2 meet the conditions of fluorescence resonance energy transfer and ratio fluorescent probe and can be used as R-SSH fluorescent probe.