Aza-BODIPY encapsulated polymeric nanoparticles as an effective nanodelivery system for photodynamic cancer treatment

Abstract

Polymeric nanoparticles represent an emerging technology in the field of theranostic nanomedicine that combines diagnostic and therapeutic applications in a single agent. In this work, iodo-substituted aza-BODIPY (AZB-I) encapsulated nanoparticles were prepared via the nanoprecipitation method using the amphiphilic poly(ethylene glycol)-block-poly(ε-caprolactone) polymer (PEG-b-PCL) for a targeted nanodelivery system. The resulting nanoparticles (AZB-I@PEG-b-PCL) exhibited a monodisperse spherical morphology with hydrodynamic average sizes ranging from 44.6 to 48.2 nm. Apart from cellular imaging through near-infrared (NIR) light, the AZB-I@PEG-b-PCL NPs can be efficiently applied for 4T1 breast cancer cell treatment upon 660 nm red LED lamp irradiation for 30 min with up to 40 μM of AZB-I content. Detection of intracellular reactive oxygen species (ROS) in cells as well as the live/dead viability/cytotoxicity assay after NIR light exposure confirmed the PDT efficacy of the NPs. Finally, the in vivo PDT capability of the obtained NPs was systematically investigated in 4T1 tumor-bearing mice. The results indicated that mice treated with AZB-I@PEG-b-PCL NPs at 32 mg kg⁻¹ (equivalent to 2 mg kg⁻¹AZB-I) showed 49.8% tumor growth inhibition at day-3 post PDT and tumor growth suppression for up to 14 days post PDT.