Polyethylene Glycol-Modified Gelatin/Polylactic Acid Nanoparticles for Enhanced Photodynamic Efficacy of a Hypocrellin Derivative In Vitro

The present study focused on the development of a novel biodegradable nanoparticle system based on polyethyleneglycol-modified gelatin (PEG-GEL) and polylactic acid (PLA) biopolymers for improving the photodynamic efficacy of cyclohexane-1,2-diamino hypocrellin B (CHA₂HB), a potent photodynamic therapeutic (PDT) agent. The CHA₂HB-loaded PEG-GEL/PLA nanoparticles showed near-spherical morphology with an average size of 190 nm at a PLA to PEG-GEL ratio of 1:3. The drug loading was sufficient enough to produce potentially toxic reactive oxygen species (ROS) needed for photodynamic therapy (PDT). Slow and controlled drug release was observed in normal conditions, whereas enzyme assistance resulted in a relatively fast release due to partial disintegration of CHA₂HB-loaded PEG-GEL/PLA nanoparticles. In vitro experiments indicated that CHA₂HB-loaded PEG-GEL-PLA nanoparticles are efficiently taken up by cancer cells such as human breast adenocarcinoma (MCF-7), human gastric sarcoma (AGS) and mice specific Dalton's lymphoma (DLA) in a time dependent manner. Further, CHA₂HB-loaded PEG-GEL/PLA nanoparticles evoked superior phototoxicity compared to free-CHA₂HB towards all the three cell lines investigated. Interestingly, PDT effectiveness was different for the different cell type studied. CHA₂HB-loaded PEG-GEL/PLA nanoparticles induced both apoptotic and necrotic cell death as a result of photoirradiation. Thus, our data suggest that PEG-GEL/PLA nanoparticles are highly effective in delivery and phototoxic enhancement of CHA₂HB against model cancer cells in vitro.