P22-26 Comparison of the Effects and Toxicity of Gold Nanorods and Gold Nanostars in Photothermal Therapy

Photothermal therapy (PTT), which destroys cancer cells by converting photon energy into heat, has emerged as a prominent treatment method due to its non-invasive nature and high selectivity 1 , 2 , 3 . Near infrared (NIR) light provides the necessary photon energy and preferred due to its deep tissue penetration 4 , 5 . The destruction of cancer cells with photothermal agents (PTAs) can occur through necrosis or apoptosis [5] . Gold (Au)-based PTAs such as Au nanorod (AuNR) and Au nanostar (AuNS) are widely studied for their effectiveness in PTT [6] . Besides, the use of laser irradiation and PTAs may have risk in damaging healthy tissues. Based on this information, this study aims to assess the effects/toxicity of AuNR and AuNS with or without 808 nm laser irradiation in human lung cancer (A549) and mouse fibroblast (L929) cells. The characterization and thermal behaviour of NPs were analyzed with related methods. The cytotoxicity of AuNR and AuNS (0.0625, 0.125, 0.25, 0.5, 1, 5, 10, and 20 µg/mL) in L929 and A549 cells, with and without 808 nm laser exposure (5 minutes), was assessed after 24- and 72-hours incubation using the MTT assay. The IC50 value (10 µg/mL) was used to examine changes in ROS formation using the (DCF-DA) method. Additionally, genotoxicity, inflammatory markers (TNF-α, IL-6, IL-10), and caspase C1q, C3, C6, and C9 levels were analyzed. SEM images of the nanoparticles were taken. After 5 minutes of laser application, it was seen that the temperature changes in the nanoparticles were within acceptable limits. After 24 hours incubation, 808 nm laser alone showed no significant cytotoxicity in L929 or A549 cells. NP induced dose-dependent toxicity, enhanced by laser exposure. AuNS was more toxic to L929 cells, while AuNR showed higher toxicity in A549 cells. After 72 hours incubation, cytotoxicity of AuNR, further increased in A549 cells with laser. ROS production increased in cancer cells treated with AuNR and laser but decreased in the healthy cells. DNA damage was found significantly higher in A549 cells treated with AuNR, while AuNS combined with laser reduced DNA damage in L929 cells. Inflammatory biomarkers were elevated in A549 cells treated with all NPs with laser. Increased caspase levels in A549 cells, particularly with laser and NP treatment, suggest that PTT may promote cell elimination via apoptosis. The results indicate that AuNR and AuNS may serve as effective PTAs for PTT. Further in vitro and in vitro studies are needed for their use in the clinic. Acknowledgement: This study was supported by Health Institutes of Türkiye (TÜSEB) (31034 awarded to Merve Güdül Bacanlı).