Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China.
Center for Advanced Quantum Studies, Department of Physics and Applied Optics Beijing Area Major Laboratory, Beijing Normal University, Beijing 100875, China.
J Am Chem Soc. 2021 May 19;143(19):7541-7552. doi: 10.1021/jacs.1c03041. Epub 2021 May 11.
Phototheranostics constitute an emerging cancer treatment wherein the core diagnostic and therapeutic functions are integrated into a single photosensitizer (PS). Achieving the full potential of this modality requires being able to tune the photosensitizing properties of the PS in question. Structural modification of the organic framework represents a time-honored strategy for tuning the photophysical features of a given PS system. Here we report an easy-to-implement metal selection approach that allows for fine-tuning of excited-state energy dissipation and phototheranostics functions as exemplified by a set of lanthanide (Ln = Gd, Yb, Er) carbazole-containing porphyrinoid complexes. Femto- and nanosecond time-resolved spectroscopic studies, in conjunction with density functional theory calculations, revealed that the energy dissipation pathways for this set of PSs are highly dependent on the energy gap between the lowest triplet excited state of the ligand and the excited states of the coordinated Ln ions. The Yb complex displayed a balance of deactivation mechanisms that made it attractive as a potential combined photoacoustic imaging and photothermal/photodynamic therapy agent. It was encapsulated into mesoporous silica nanoparticles (MSN) to provide a biocompatible construct, YbL@MSN, which displays a high photothermal conversion efficiency (η = 45%) and a decent singlet oxygen quantum yield (Φ = 31%). Mouse model studies revealed that YbL@MSN allows for both photoacoustic imaging and synergistic photothermal- and photodynamic-therapy-based tumor reduction in vivo. Our results lead us to suggest that metal selection represents a promising approach to fine-tuning the excited state properties and functional features of phototheranostics.
光热治疗是一种新兴的癌症治疗方法，其中核心的诊断和治疗功能被整合到一个单一的光敏剂（PS）中。要充分发挥这种治疗方式的潜力，就需要能够调整所研究的 PS 的光敏特性。对有机框架的结构修饰是调整特定 PS 系统光物理特性的一种久经考验的策略。在这里，我们报告了一种易于实施的金属选择方法，该方法允许精细调整激发态能量耗散和光热治疗功能，例如一组含镧系元素（Ln = Gd、Yb、Er）咔唑的卟啉类配合物。飞秒和纳秒时间分辨光谱研究，结合密度泛函理论计算，表明该系列 PS 的能量耗散途径高度依赖于配体的最低三重态激发态与配位 Ln 离子的激发态之间的能量差。Yb 配合物显示出一系列失活机制的平衡，使其成为一种有吸引力的潜在的光声成像和光热/光动力治疗联合剂。它被包裹在介孔硅纳米粒子（MSN）中，提供了一种具有生物相容性的构建体 YbL@MSN，其具有高的光热转换效率（η=45%）和良好的单线态氧量子产率（Φ=31%）。小鼠模型研究表明，YbL@MSN 允许在体内进行光声成像和协同光热和光动力治疗以减少肿瘤。我们的结果表明，金属选择是一种精细调整光热治疗剂的激发态性质和功能特性的有前途的方法。
