Near-infrared light (NIR)-responsive nanoliposomes combining photodynamic therapy and chemotherapy for breast tumor control

Light-responsive carriers have been used for the controlled release of antitumor drugs in recent years. However, most light-responsive vectors require high-energy ultraviolet or visible light to achieve local drug release, and ultraviolet light would cause cellular damage. Near-infrared light has a deeper tissue-penetration depths and minimal harm to tissues, but it is difficult to cleave the chemical bond directly. The aim of this study is to develop a novel near-infrared light-responsive carrier for local release of antitumor drugs. Unsaturated phospholipids can be oxidized by singlet oxygen to achieve liposomal drug release, and singlet oxygen can be produced by photosensitizer under light irradiation. A new near-infrared light-responsive nanoliposome was designed that imparts light-triggered local drug release. Nanoliposomes, which were composed of matrix phospholipids and unsaturated phospholipids, were prepared by ammonium sulfate gradient method, and loaded with antitumor drug doxorubicin (DOX) and photosensitizer 1,4,8,11,15,18,22,25-octabutoxypalladium phthalocyanine. Under near-infrared light, photosensitizers could produce singlet oxygen and damage tumor cells by photodynamic therapy. Simultaneously, the unsaturated phospholipids were oxidized by singlet oxygen and result in DOX release, causing sustained cell damage by chemotherapy. Near-infrared light-responsive nanoliposomes exhibit enhanced anticancer activity owing to combined treatment of photodynamic therapy and chemotherapy. A new platform is thus offered for designing effective intracellular drug-release systems, holding great promise for future cancer therapy.