Assemblies of indocyanine green and chemotherapeutic drug to cure established tumors by synergistic chemo-photo therapy

Abstract

Indocyanine green (ICG), a safe and clinically approved near-infrared (NIR) dye, was recently explored as a potential photosensitizer due to its excellent photophysical properties. However, ICG tends to form aggregations in physiological solution, causing fluorescence quenching, fast blood clearance and thereby inefficient tumor accumulation. Herein, we report ICG-based nanodrug delivery systems formed by self-assembly of ICG and chemotherapeutic drugs without any excipients for combined chemo- and photo-therapy. Taking advantage of the amphiphilic aromatic structure, ICG readily bounded with hydrophobic aromatic drugs such as SN38 and formed well-dispersible nanoparticles, which reduced its aggregation-induced quenching and thus greatly improved its photodynamic efficiency. The loaded hydrophobic drugs elicited chemotherapy synergizing the photodynamic therapy, giving rise to much enhanced antitumor activity in vitro and in vivo against human glioblastoma cells and breast cancer cells upon NIR irradiation. The work demonstrates the fabrication of readily translational nanoformulations of hydrophobic drugs using amphiphilic drugs.

Keywords: Combination therapy; Indocyanine green; Photodynamic therapy; Photothermal therapy; Self-assembly; Small molecular prodrug.