Synthesis And Biological Application Of Near-Infrared Triarylamine Aggregation-induced Emission Photosensitizer

Photodynamic therapy（PDT）,as a non invasive,low toxic,and highly selective cancer treatment method,has attracted widespread attention.Photosensitizers play a key role in PDT process.Most traditional PSs show poor solubility in water,and suffer from aggregation-caused quenching（ACQ）problem with reducing the generation of reactive reactive oxygen species（ROS）.Triphenylamine（TPA）dyes have typical aggregation-induced emission（AIE）properties,and some TPA dyes with push-pull electron effects have excellent lighting ROS ability,which can be used for fluorescence imaging guild PDT.Herein,we report a series of TPA-based PS with the near-infrared emission.Using the TPA as the skeleton,the low-energy absorption and ROS generation of PS was modulated by push-pull electron effects and-conjugation effects.The phototoxicity and sensing ability of PSs to tumor cells were detailedly investigated.Some interesting results are shown in below:（1）Synthesis and properties of near infrared emission TPA photosensitizers:Five new TPA-based photosensitizers TBZPYME-n（n=1?5）were obtained with different substituents（nitro,aldehyde,hydrogen,methoxy）in the TPA donor moiety,and benzothiadiazole-pyridinium group as the energy receptor.Compared to their precursor TBZPY-n（n=1?5）,TBZPYME-n has a long wavelength absorption spectrum and high ROS generation efficiency.With the increase of the electron donor ability of the substituents,the maximum absorption spectrum of TBZPYME-n in aqueous solution shifts from 454 nm in TBZPY-1 to 532 nm in TBZPY-5.Simultaneous,the efficiency of ROS generation was also increased with increasing the energy donor ability,which is higher than commercial photosensitizer RB.However,all the PSs show weak fluorescence.The TBZPYME-5 photosensitizer had an excellent PDT effect on cancer cells with 660 laser irradiation.（2）Hydrogen peroxide degradation AIE photosensitizer:A new AIE photosensitizer TBZPYBE was obtained from the precursor TBZPY-4 of chapter two.In aqueous solution,TBZPYBE has a good ROS generation under white light irradiation,but its fluorescence is very weak.After adding H₂O₂,the ROS production ability decreases,but its fluorescence increases.TBZPYBE has been successfully used for PDT treatment of cancer cells.Due to its reduced ROS efficiency after reacting with tumor marker H₂O₂,it can effectively solve the toxic and side effects of photosensitizer residues on normal tissues.At the same time,TBZPYBE is also used for fluorescence enhanced imaging to distinguish between normal and cancer cells,achieving integration of diagnosis and treatment.