Wu Fapu, Lu Yingxi, Mu Xueluer, Chen Zhitai, Liu Shengsen, Zhou Xianfeng, Liu Shaofeng, Li Zhibo
Key Laboratory of Biobased Polymer Materials of Shandong Provincial Education Department, College of Polymer Science and Engineering, Qingdao University of Science and Technology, 53 Zhengzhou Road, Qingdao 266042, P. R. China.
College of Material Science and Engineering, Qingdao University of Science and Technology, Qingdao 266042, P. R. China.
ACS Appl Mater Interfaces. 2020 Jul 22;12(29):32388-32396. doi: 10.1021/acsami.0c07608. Epub 2020 Jul 8.
Organic small-molecule-based photothermal agents such as cyanine dyes have received increasing attention in developing novel cancer therapies with potential clinical utility but suffer from poor stability, low photothermal efficiency, and limited accumulation at tumor sites in molecular forms. Self-assembly of small-molecule dyes into supramolecular assemblies may address these concerns by controlling the molecular organization of dye monomers to form structures of a higher order. Among them, H-aggregates of dyes favor face-to-face contacts with strongly overlapping areas, which always have a negative connotation to exhibit low or no fluorescence in most cases but may emanate energy in nonradiative forms such as heat for photothermal cancer therapy applications. Here, the synergistic self-assembly of cyanine dyes into H-aggregates is developed as a new supramolecular strategy to fabricate small-molecule-based photothermal nanomaterials. Compared to the free cyanine dyes, the H-aggregates assembled from pyrene or tetraphenylethene (TPE) conjugating cyanine exhibit the expected absorption spectral blue shift and fluorescence self-quenching but unique photothermal properties. Remarkably, the obtained H-aggregates are saucer-shaped nanoparticles that exhibit passive tumor-targeting properties to induce imaging-guided photothermal tumor ablation under irradiation. This supramolecular strategy presented herein may open up new opportunities for constructing next-generation small-molecule-based self-assembly nanomaterials for PTT cancer therapy in clinics.
基于有机小分子的光热剂，如菁染料，在开发具有潜在临床应用价值的新型癌症治疗方法方面受到了越来越多的关注，但它们存在稳定性差、光热效率低以及以分子形式在肿瘤部位的积累有限等问题。小分子染料自组装成超分子聚集体可以通过控制染料单体的分子组织以形成更高阶的结构来解决这些问题。其中，染料的H-聚集体有利于面对面接触且具有强烈重叠的区域，在大多数情况下，这些区域总是具有负面含义，表现出低荧光或无荧光，但可能以非辐射形式（如热）释放能量用于光热癌症治疗应用。在此，将菁染料协同自组装成H-聚集体作为一种新的超分子策略，用于制备基于小分子的光热纳米材料。与游离菁染料相比，由芘或四苯乙烯（TPE）共轭菁组装而成的H-聚集体表现出预期的吸收光谱蓝移和荧光自猝灭，但具有独特的光热性质。值得注意的是，所获得的H-聚集体是碟形纳米颗粒，具有被动肿瘤靶向特性，可在照射下诱导成像引导的光热肿瘤消融。本文提出的这种超分子策略可能为构建用于临床光热疗法癌症治疗的下一代基于小分子的自组装纳米材料开辟新的机会。
