Photosensitizer-encapsulated amphiphilic chitosan derivative micelles: Photoactivity and enhancement of phototoxicity against human pancreatic cancer cells

[Display omitted] •Photosensitizer-encapsulated amphiphilic chitosan derivative micelles were prepared.•They exhibited controlled photoactivity.•The photoactivity of Photosan was suppressed in the micelles.•The micelles showed strong phototoxicity against human pancreatic cancer cells.•They could be used as a potential photodynamic therapy in pancreatic cancer. Photosensitizer-encapsulated amphiphilic chitosan derivative (Photosan-DA-Chit) micelles with controlled photoactivity have been prepared using a simple self-assembly method in phosphate-buffered saline (pH 6.2). The fluorescence quantum yield and fluorescence lifetime of the Photosan-DA-Chit micelles were lower than those of free Photosan, which indicated that the micelles were suppressing the photoactivity of Photosan. However, upon incubation with human pancreatic cancer cells (i.e., Panc-1 cells), the Photosan-DA-Chit micelles showed higher fluorescence activity than free Photosan and generated higher levels of reactive oxygen species under laser illumination. The Photosan-DA-Chit micelles therefore exhibited strong phototoxicity, which led to significant levels of apoptosis in the Panc-1 cells. In the absence of light, however, the Photosan-DA-Chit micelles showed no cytotoxicity. These results indicated that they could be used as a potential photodynamic therapy in pancreatic cancer.