Hypericin-Loaded Chitosan Nanoparticles for Enhanced Photodynamic Therapy in A549 Lung Cancer Cells

Nanoparticles (NPs) are one of the most preferred materials in drug release systems. Photodynamic therapy (PDT) acts by activating natural components with light to form radicals and causing death due to intracellular toxicity. Hypericin (HY) which was derived from Hypericum perforatum was used as a photosensitizer and anticancer agent. It is already known that cytotoxicity, antiproliferative and antitumor effects of HY-mediated PDT. However, HY is clustered in an aqueous environment which decreases its efficiency. Therefore, it was preferred to be used with NP-based carriers. In this study, HY-loaded chitosan NPs (HY-CH-NPs) were prepared for in vitro assessment. It was aimed to increase the cytotoxic effect of HY by prolonging the duration and uptake of HY action in the A549 lung cancer cells after PDT irradiation (6 J/cm 2 ) with fluorescent lamps. HY-CH-NPs were characterized to examine their size and surface change with dynamic light scattering (DLS) and scanning electron microscopy (SEM), and it was achieved that the particles were below 400 nm diameter. All HY-CH-NPs showed a peak at around 1260 cm −1 according to FTIR spectrum. With the FITC staining, the penetration of NPs into the cell was demonstrated. And the drug (HY) loading efficiency was found as 3%. The cell viability decreased to 56% in the HY-CH-NP group after 48 h incubation in MTT assay. The amount of ROS in the HY-CH-NP 600 nM group was formed 1.6 times higher in the DCFDA analysis, and the total cell death was 40% in the AO/PI staining. It was observed that nanoparticles were able to cross the cell membrane barrier, and as a result of it, apoptosis and secondary necrosis were induced in the cancer cell. Lactate dehydrogenase release was also the highest in the 600 nM HY-CH-NP group, indicating increased necrotic cell death. Graphical Abstract