Preparation and evaluation of photo-sensitive reactive oxygen species responsive liposomes

Photo-sensitive reactive oxygen species (ROS) responsive liposomes loaded with 1,4,8,11,15, 18,22,25-octabutoxypalladium phthalocyaninePdPC(OBu)₈ and doxorubicin hydrochloride (DOX) (LPD) were prepared by (NH4)₂SO₄-gradient method. LPD was characterized with transmission electron microscopy (TEM), dynamic light scattering particle size, zeta potentials, photo-sensitive ROS-responsive DOX release behaviors and the serum stability in vitro. LPD cytotoxicity, DOX uptake and singlet oxygen production in MCF-7 cells were evaluated. The results showed that the particle size of LPD was (169.3 ±1.2) nm, PDI of LPD was 0.198 ±0.003 and zeta potentials of LPD was (-39.8 ±0.8) mV. The accumulated release of DOX reached 95.5% in 5 min under 730 nm laser irradiation (300 mW·cm^-2). The DOX uptake of liposome was increased and ¹O₂ was generated. The half inhibition concentration (IC₅₀) of DOX in LPD with irradiation group was decreased by 85.7% and no irradiation group was decreased by 67.9% compared with free DOX group in MCF-7 cells. Therefore, photo-sensitive ROS-responsive liposomes would be a promising drug delivery system for tumor therapy.