南方科技大学田雷蕾团队报道了开壳有机自由基，在增强近红外光激活光敏剂抗肿瘤光催化反应中的作用。相关研究成果于2025年1月20日发表在国际顶尖学术期刊《德国应用化学》。

以不成对电子为特征的开壳自由基材料因其独特的光电特性，在材料科学领域取得了革命性的突破。然而，有机自由基参与光动力疗法（PDT）的报道或讨论很少。

该文研究了两种光敏剂类似物。与封闭壳2AM-CS相比，具有扩展π共轭的4AM-OS表现出开放壳自由基特征和增强的I型光动力活性。4AM-OS显示出热可及的三重态特征，导致更多的未配对电子在较高温度下沿着π共轭骨架离域。因此，4AM-OS的温度依赖性光动力活性证实了其与开壳电子结构的关联。

由于开壳4AM-OS中的未配对电子更加离域并产生额外的电子能态，光诱导电荷转移被促进以促进I型光动力反应。这一观察解决了与近红外（NIR）光敏剂（如4AM-OS）相关的挑战，尽管其具有优越的组织穿透深度，但由于NIR光提供的能量有限，4AM-OS在PDT中的疗效通常较低。

总体而言，阐明有机自由基在光动力反应中的有益作用，将为开发高性能近红外光敏剂，和提高PDT治疗深部病变的疗效带来革命性的突破。

附：英文原文

Title: The Role of Open-Shell Organic Radical in Enhancing Anti-Tumor Photocatalysis Reaction of NIR Light-Activated Photosensitizer

Author: Heng Li, Ying Gu, Yafei Ding, Jia Huang, Zhiqiang Yang, Pengbo Ding, Mengying Wang, Liang Han, Bing Yang, Liang Guo, Yuanzhu Zhang, Feng He, Leilei Tian

Issue&Volume: 2025-01-20

Abstract: Open-shell radical materials, which are characterized by unpaired electrons, have led to revolutionary breakthroughs in material science due to their unique optoelectronic properties. However, the involvement of organic radicals in photodynamic therapy (PDT) has rarely been reported or discussed. This work studies two photosensitizer analogs. 4AM-OS with extended π-conjugation exhibits open-shell radical characters and enhanced type-I photodynamic activity compared with closed-shell 2AM-CS. 4AM-OS displays the thermally accessible triplet-state character, resulting in more unpaired electrons delocalized along the π-conjugated backbone at higher temperatures. Accordingly, the temperature-dependent photodynamic activity of 4AM-OS confirms its association with the open-shell electronic structure. As the unpaired electrons in open-shell 4AM-OS are more delocalized and generate additional electronic energy states, photo-induced charge transfer is promoted to facilitate type-I photodynamic reactions. This observation addresses the challenge associated with near-infrared (NIR) photosensitizers, such as 4AM-OS, which often demonstrate low efficacy in PDT due to the limited energy provided by NIR light despite its superior tissue penetration depth. Overall, clarifying the beneficial role of organic radicals in photodynamic reactions will bring revolutionary breakthroughs to developing high-performance NIR photosensitizers and promoting the efficacy of PDT for deep-seated lesions.

DOI: 10.1002/anie.202423023

Source: https://onlinelibrary.wiley.com/doi/10.1002/anie.202423023