HIF‐1α‐inhibited Nanophotosensitizers for Near‐infrared Fluorescence Imaging‐guided Enhanced Photodynamic Therapy

Abstract Photodynamic therapy (PDT) holds great potential in cancer therapy by virtue of its high precision, non‐invasiveness and low side effect. However, the hypoxic environment of solid tumor significantly restricts the efficacy of PDT. To improve the hypoxic microenvironment, inhibiting the hypoxia‐inducible factor 1α (HIF‐1α) is a rational approach. However, the related small molecule inhibitors suffer from the issue of poor tumor targeting. Herein, we design a nanophotosensitizer AmPPa NP which can inhibit HIF‐1α and conduct PDT with improved efficacy. AmPPa NP is prepared by first encapsulating a hydrophobic NIR photosensitizer mPPa into a carboxyl‐rich amphiphilic copolymer PSMA‐PEG, and then loading a positively charged HIF‐1α inhibitor acriflavine (ACF) on the surface of nanoparticle via electrostatic interaction. Under 635 nm laser irradiation, mPPa within nanoparticles can not only generate ¹O₂ for PDT but also emit NIR fluorescence signal for tumor imaging. In addition, such design makes ACF can be selectively released under acidic tumor microenvironment. Compared with mPPa NP without ACF loading, AmPPa NP can effectively inhibit HIF‐1α and shows improved PDT efficacy both in vitro and in vivo. This study thus provides a nanotheranostic platform for NIR fluorescence imaging‐guided enhanced PDT.