Multifunctional nano-photosensitizer: A carrier-free aggregation-induced emission nanoparticle with efficient photosensitization and pH-responsibility

Aggregation-induced emission photosensitizers (AIE-PSs) with strong photosensitization perform well in efficient tumor photodynamic therapy. However, small molecule AIE-PSs will cause cytotoxicity of normal cells for the lack of targeting. Researchers used nanocarriers to improve the targeting of photosensitizers and reduce toxic side effects on normal tissues, which would also bring about the safety problems of nanocarriers. In this study, we developed a novel pH-responsive carrier-free AIE nano-photosensitizer (AIE-NPS) self-assembled by amphiphilic AIE photosensitizer (HD-APNNA). This carrier-free AIE-NPS overcomed the safety problems of nanocarriers and the protonation and deprotonation of carboxyl groups of HD-APNNA endowed the AIE-NPS pH-responsibility. Meanwhile, The ROS production efficiency of AIE-NPS is as high as 56.7%, which is superior to the commonly used photosensitizers in clinic. As a result, the AIE-NPS showed a remarkable photodynamic therapeutic effect in vitro under white light (50 mW cm−2). The tumor-bearing mice model demonstrated that the AIE-NPS could effectively accumulate in solid tumors and inhibit the growth of tumors. This work provides a novel strategy and some useful information for the AIE photodynamic therapy and benefits for the clinic application of the carrier-free nanodrugs in the future.