CAS Key Laboratory for Biomedical Effects, of Nanomaterials and Nanosafety, National Center for Nanoscience and Technology, Beijing, 100190, P.R. China.
School of Public Health, Jilin University, Changchun, 130021, P.R. China.
Chem Asian J. 2018 Nov 16;13(22):3540-3546. doi: 10.1002/asia.201800859. Epub 2018 Aug 27.
In recent years, one of main obstacles in a photodynamic therapy (PDT) process has been that most photosensitizers for PDT are excited by visible light with limited penetrating ability; thus most applications of PDT are for superficial treatments. One of the methods to increase the treatment depth is to introduce a two-photon-active technique into PDT, known as TP-PDT. The difficulty here is to obtain photosensitizers with a large enough two-photon absorption cross-section. In this work, an organic nanocomplex, composed of the two-photon nanoaggregate as the core and photosensitizer as the shell, has been constructed. Photosensitizers could be excited indirectly through a fluorescence resonance energy transfer (FRET) mechanism after the two-photon core was excited by a two-photon laser. The FRET efficiency was extremely high, owing to sufficient energy donors and stable energy acceptors. In this way, a photosensitizer could induce two-photon toxicity for improving the treatment depth in PDT. The nanocomplexes were prepared through a molecular assembly method, which avoided complicated reactions for synthesizing two-photon photosensitizers. The assembly method would expand the selection of photosensitizers and two-photon dyes, and endow traditional photosensitizers with a larger two-photon absorption cross-section for TP-PDT.
近年来，光动力疗法（PDT）过程中的主要障碍之一是，大多数 PDT 光敏剂都被可见光激发，穿透能力有限；因此，PDT 的大多数应用都是用于表面治疗。增加治疗深度的方法之一是将双光子活性技术引入 PDT，称为双光子 PDT（TP-PDT）。这里的难点是获得具有足够大双光子吸收截面的光敏剂。在这项工作中，构建了一种有机纳米复合物，由双光子纳米聚集体作为核和光敏剂作为壳组成。双光子核被双光子激光激发后，光敏剂可以通过荧光共振能量转移（FRET）机制间接被激发。由于有足够的能量供体和稳定的能量受体，FRET 效率非常高。这样，光敏剂可以诱导双光子毒性，从而提高 PDT 的治疗深度。纳米复合物是通过分子组装方法制备的，这种方法避免了合成双光子光敏剂的复杂反应。组装方法将扩大光敏剂和双光子染料的选择范围，并赋予传统光敏剂更大的双光子吸收截面，用于 TP-PDT。
