Enhanced Nuclear Localization of Photosensitizer Using Artificial Oil Bodies for Photodynamic Therapy

Photodynamic therapy (PDT) is a light-activated photochemical reaction that induces localized tissue damage for the treatments of cancers and other nonmalignant conditions through the generation of reactive oxygen species. In the clinic, patients treated with PDT reveal strong skin photosensitivity and thus should be kept away from direct sunlight. In our previous study, we demonstrated that the skin phototoxicity of meta-tetra(hydroxyphenyl)chlorin (m-THPC), a photosensitizer used in the clinic, can be significantly reduced after micellar encapsulation. In this present work, m-THPC was loaded into artificial oil bodies (AOBs) to improve its biocompatibility with self-aggregation. Our results show that the m-THPC-loaded oil bodies with particle size around 100 nm significantly enhanced the nuclear localization of m-THPC, whereas m-THPC-loaded Pluronic® F68 micelles were only observed in the cytosol. In addition, m-THPC-loaded oil bodies had better PDT efficacy than those m-THPC-loaded polymeric micelles. It is speculated that the nuclear accumulation of m-THPC using AOBs as drug carriers significantly enhanced the PDT effects in cancer cells. Thus, m-THPC-loaded oil bodies with improved anticancer efficacy have a great potential for developing nanotechnology-based PDT.