Photosensitizers (PSs) with effective two-photon absorption in the therapeutic window are the key to two-photon photodynamic therapy. However, the traditional exogenous PSs usually lead to rejection in the body. Besides, the precise visualization of treatments proposes new demands and challenges for the design of PSs. Accordingly, in this work, a series of quasi-intrinsic PSs are obtained based on the artificial base 2-amino-8-(1′-β-d-2′-deoxyribofuranosyl)-imidazo[1,2-α]-1,3,5-triazin-4(8H)-one (P). The calculations show that the structural modification could enhance the two-photon absorption and fluorescence emission, which is beneficial for tumor localization. Furthermore, the reduced singlet–triplet energy gaps and enhanced spin–orbit coupling contribute to the rapid intersystem crossing process, which results in a triplet state with high quantum yields. To ensure the phototherapeutic performance of the newly designed PSs, we also examined the vertical electron affinity and vertical ionization potential for generation of superoxide anions, as well as the T₁ energy required to produce singlet oxygen.

中文翻译：

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设计具有荧光成像和光动力疗法双重功能的准本征光敏剂


在治疗窗中具有有效双光子吸收的光敏剂 （PS） 是双光子光动力疗法的关键。然而，传统的外源性 PS 通常会导致体内排斥反应。此外，处理的精确可视化对 PSs 的设计提出了新的要求和挑战。因此，在本工作中，基于人工碱基 2-氨基-8-（1′-β-d-2′-脱氧呋喃核糖基）-咪唑[1,2-α]-1,3,5-三嗪-4（8H）-酮 （P） 获得了一系列准内禀 PS。计算表明，结构修饰可以增强双光子吸收和荧光发射，有利于肿瘤定位。此外，减小的单重态-三重态能隙和增强的自旋-轨道耦合有助于快速的系统间交叉过程，从而产生具有高量子产率的三重态。为了确保新设计的 PSs 的光疗性能，我们还检查了产生超氧阴离子的垂直电子亲和力和垂直电离电位，以及产生单线态氧所需的 T₁ 能量。