Random versus Block Glycopolymers Bearing Betulin and Porphyrin for Enhanced Photodynamic Therapy

Porphyrins and their derivatives, representing the second-generation photosensitizers, can generate reactive oxygen species (ROS) and kill tumors upon light irradiation. To compensate for the fluorescence quenching and reduced ROS production caused by aggregation and rigid inherent hydrophobicity of porphyrins, a series of comparable random and block glycopolymers bearing betulin and porphyrin were prepared via RAFT polymerization. Betulin was introduced into the copolymers to decrease aggregation-induced quenching of porphyrins and to improve the photodynamic therapy (PDT) efficiency of copolymers. The characteristics, self-assembly, and photophysical chemistry properties of these copolymers were systemically studied. The effect of polymer structure on photophysical chemistry properties and cellular interaction was investigated as well to demonstrate their potential targeting for PDT applications.