Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, Jilin University, Liutiao Road 2#, Changchun 130061, China.
Phys Chem Chem Phys. 2018 Dec 19;21(1):281-291. doi: 10.1039/c8cp06050a.
The level of hydrogen peroxide (H2O2) plays an essential role in regulating biological processes. The in vivo or in vitro detection of H2O2 in deep tissues by utilizing two-photon (TP) fluorescent probes can significantly alleviate the detection damage inflicted onto living organisms as well as facilitate high-resolution imaging when compared with one-photon (OP) fluorescent probes. However, few TP fluorescent probes possess both high fluorescence efficiency and easily distinguishable spectra for measuring H2O2. Therefore, an in-depth understanding of the relationship between the electronic structure and TP fluorescent properties and fabricating probes with excellent performance are still challenging. Consequently, we designed a series of benzocoumarin-based ratiometric TP fluorescent probes and corresponding product molecules for H2O2 detection. Thereafter, we theoretically evaluated the TP recognition performance of these compounds and studied the relationship between their molecular structure and TP performance by means of time-dependent density functional theory and quadratic response theory. Moreover, we determined their spectral properties and fluorescence efficiencies. Fortunately, in this study, we were able to propose an excellent TP probe BC-3 and the corresponding product molecule DCCA-3, which exhibit large TPA cross-sections in the NIR region (3420 GM/988 nm; 316 GM/939 nm) and large Stokes (116 nm; 60 nm) and emission (225 nm) shifts. Therefore, this probe enables the simultaneous NIR and TP imaging of H2O2, which is a unique ability and has never been previously reported. Moreover, we comprehensively investigated the effect of the benzene-fused position in the coumarin backbone on the transition dipole moment and nonradiative decay channels, explaining the fluorescence near-quenching mechanism of benzo[f]coumarin derivative DCCA-4 for the first time.
过氧化氢 (H2O2) 的水平在调节生物过程中起着至关重要的作用。利用双光子 (TP) 荧光探针在体内或体外检测深层组织中的 H2O2，可以显著减轻对生物体的检测损伤，并有利于高分辨率成像，与单光子 (OP) 荧光探针相比。然而，很少有 TP 荧光探针具有高荧光效率和易于区分的光谱，用于测量 H2O2。因此，深入了解电子结构与 TP 荧光性质之间的关系，并制造具有优异性能的探针仍然具有挑战性。因此，我们设计了一系列基于苯并香豆素的比率型 TP 荧光探针和相应的产物分子，用于 H2O2 的检测。此后，我们通过时间依赖密度泛函理论和二次响应理论理论上评估了这些化合物的 TP 识别性能，并研究了它们的分子结构与 TP 性能之间的关系。此外，我们确定了它们的光谱性质和荧光效率。幸运的是，在这项研究中，我们能够提出一个出色的 TP 探针 BC-3 和相应的产物分子 DCCA-3，它们在近红外区域 (3420 GM/988 nm; 316 GM/939 nm) 具有大的 TPA 截面和大的斯托克斯 (116 nm; 60 nm) 和发射 (225 nm) 位移。因此，该探针能够同时对 H2O2 进行近红外和 TP 成像，这是一种独特的能力，以前从未有过报道。此外，我们全面研究了香豆素骨架中苯并环的融合位置对跃迁偶极矩和非辐射衰减通道的影响，首次解释了苯并[f]香豆素衍生物 DCCA-4 荧光近猝灭的机制。
