| Institution: | 1. State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian, 116024 People's Republic of China;2. Fluorescence Research Group, Singapore University of Technology and Design, 8 Somapah Road, 487372 Singapore, Singapore;3. State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian, 116024 People's Republic of China
Shenzhen Research Institute, Dalian University of Technology, Nanshan District, Shenzhen, 518057 China;4. Department of Pathophysiology, Dalian Medical University, Dalian, 116044 China |
| Abstract: | Upconversion luminescent (UCL) triggered photodynamic therapy (PDT) affords superior outcome for cancer treatment. However, conventional UCL materials which all work by a multiphoton absorption (MPA) process inevitably need extremely high power density far over the maximum permissible exposure (MPE) to laser. Here, a one-photon absorption molecular upconversion sensitizer Cy5.5-Br based on frequency upconversion luminescent (FUCL) is designed for PDT. The unusual super heavy atom effect (SHAE) in Cy5.5-Br strongly enhances its spin-orbit coupling (0.23 cm?1), triplet quantum yield (11.1 %) and triplet state lifetime (18.8 μs) while the potential hot-band absorption of Cy5.5-Br is well maintained. Importantly, Cy5.5-Br can efficiently target the tumour site and kill cancer cells by destroying mitochondria under a biosafety MPE to 808 nm laser. The photostability and antitumor results are obviously superior to that of a Stokes process. This work provides a design criterion for FUCL dyes to realize effective PDT upon a biosafety optical density, possibly bringing more clinical benefits than conventional MPA materials. |
