Cationic triblock copolymer micelles deliver anionic spacer chains substituted aluminum phthalocyanine for enhancement intracellular photodynamic efficacy

A novel spacer chains substituted aluminum phthalocyanine (Pc), naming tetra-carboxylaminohexanoicsulfonyl aluminium phthalocyanine 4 was synthesized. Its structure was characterized by elemental analysis, IR, 1H NMR and MS. Polyion complex micelle (PIC) between the 4 and amphiphilic triblock copolymer poly(L-lysin)-block-poly(ethylene glycol)-block-poly(L-lysin) (PLL-b-PEG-b-PLL) was formed via an electrostatic interaction between the positively charged poly(L-lysin)(PLL) segment and negatively charged periphery of the 4. Dynamic light scattering (DLS) and atom force microscopy (AFM) image showed that 4-loaded PIC formed a spherical nanocarrier micelle with approximately 85 nm in diameter. The fluorescence intensity and lifetime of 4-loaded PIC were significantly enhanced by the incorporation 4 into PIC nanocarrier. The time-dependent intracellular uptake amount and in vitro photodynamic photocytotoxicity of the 4 within the nanocarrier were drastically improved compared with the free 4.