EGFR-targeting Peptide Conjugated pH-sensitive Micelles as a Potential Drug Carrier for Photodynamic Detection and Therapy of Cancer

Multifunctional theranostics have recently been intensively explored to optimize the efficacy and safety. Herein, we report multifunctional micelle that constructed from graft copolymer PEGMA-co-PDPA and diblock copolymer mPEG-b-PCL as the carrier of hydrophobic photosensitizer, chlorin e6 (Ce6) for simultaneous fluorescence imaging and photodynamic therapy. The functional inner core of PEGMA-co-PDPA exhibited pH stimulate to accelerate drug release under slightly acidic microenvironments of tumors and the outer shell of micelles with epidermal growth factor receptor (EGFR)-targeting GE11 peptides for active targeting of EGFR-overexpressing cancer cells. The results demonstrate that GE11-conjugated chlorin e6-loaded micelles (GE11-Ce6-micelles) with particle size around 100 nm and the micelles had well defined core shell structure which was evaluated by TEM. In the in vitro cellular uptake studies, GE11-Ce6-micelles exhibited a higher amount of intracellular uptake of chlorin e6 in HCT116 cancer cells (EGFR high expression) via receptor-mediated endocytosis, in contrast with the time-dependent passive uptake of the non-targeted Ce6-micelles, thereby providing a effective photocytotoxic effect on the HCT116 cancer cells. In vivo study revealed that GE11-Ce6-micelles exhibited tumor targeting for photodynamic detection and excellent inhibition on tumor growth after irradiation, indicating that GE11-Ce6-micelles could be successfully applied to the effective fluorescence imaging and photodynamic therapy of cancer.