Photoelectron Transfer at ZnTPyP Self-Assembly/TiO 2 Interfaces for Enhanced Two-Photon Photodynamic Therapy

• Published in: ACS applied materials & interfaces 2018-01, Vol.10 (2), p.1492-1498
• Main Authors: Liu, Yanyan, Meng, Xianfu, Wang, Han, Tang, Zhongmin, Zuo, Changjing, He, Mingyuan, Bu, Wenbo
• Format: Article
• Language: English
• Subjects: HeLa Cells; Humans; Photochemotherapy; Photosensitizing Agents; Titanium - chemistry
• ISSN: 1944-8244; 1944-8252
• DOI: 10.1021/acsami.7b14451

Two-photon (TP) absorption nanomaterials are highly desirable for deep-tissue clinical diagnostics and orthotopic disease treatment. Here, a well-designed core/shell nanostructure was successfully synthesized with a ZnTPyP self-assembly nanocrystal (ZSN) inner core coated by a homogeneous TiO layer outside (ZSN-TO). The ZSN is a good photosemiconductor, showing both one-photon (OP) and TP absorption properties for red fluorescence emission and electron-hole pair generation; TiO with good biocompatibility acts as the electron acceptor, which can transfer photoelectron from ZSN to TiO for highly effective electron-hole separation, favoring the production of long-life superoxide anion (O ) by electrons and oxygen and strong oxidizing hydroxyl radical (•OH) by holes and surrounding H O. Once pretreated with ZSN-TO, the simultaneous OP-405 nm or TP-800 nm laser stimulation and fluorescent imaging of reactive oxygen species (ROS) showed dynamical and continuous generation of ROS in HeLa cells, with cytotoxicity significantly increasing via the type-1-like photodynamic therapy process. The results demonstrated that the combination of organic ZSN with inorganic TiO has great applications as an excellent photosensitizer for deep-tissue fluorescent imaging and noninvasive disease treatment via TP photodynamic therapy.