Effect of Silver Nanoparticles on Improving the Efficacy of 5-Aminolevulinic Acid-Induced Photodynamic Therapy

The most important limitation of 5-aminolevulinic acid (5-ALA)-induced photodynamic therapy (PDT) is the efficacy of the cells in converting 5-ALA to protoporphyrin IX. The present study aimed to investigate the effectiveness of silver nanoparticles (AgNPs) with the photosensitivity at the surface plasmon resonance wavelength on 5-ALA-mediated PDT.
Material and First of all, the toxicity of 5-ALA, AgNPs, and combined 5-ALA and AgNPs was evaluated on DFW cell line derived from melanoma. After choosing the optimal concentration, both pulsed and continuous light irradiations were conducted at different doses using a light‑emitting diode source in the groups receiving 5-ALA, AgNPs, as well as 5-ALA and AgNPs combination, and the controls. The cell survival was evaluated 24 h after irradiation using MTT assay. According to the results, light exposure did not significantly change cell survival in the absence or presence of AgNPs. However, light exposure in the presence of 5-ALA and AgNPs/5-ALA combination caused a significant reduction in the cell survival. The necessary light exposure to induce 50% cell death (ED50) in the presence of 5-ALA was 1280 mJ/cm2; however, this value was 280 mJ /cm2 in the presence of combined AgNPs and 5-ALA. As the findings indicated, PDT had a higher efficacy in the presence of combined 5-ALA and AgNPs than in the sole 5-ALA presence. Nonetheless, further studies are required to evaluate the definitive mechanism of these findings.