Palladium nanoparticles (Pd-NPs) have various applications in industries, such as: Biomedicine, Sewage treatment, Electronics, and Catalytic processes. Different studies on NP have shown that they have negative impacts on different cell categories in vitro. Despite extensive considerations, the molecular mechanism of Pd-NPs toxicity has remained elusive thus far. Therefore, in this paper, we investigated the toxicity of Pd-NPs by evaluating their effects on human lymphocyte. Blood lymphocyte cells were initially isolated by ficoll solution and were exposed to Pd-NPs and Pd (II) ions. Then, we examined oxidative stress, cell cycle and apoptosis employing flow cytometry. We found the NPs administration suppressed cell growth which in turn resulted in cell apoptosis. Also, cell cycle stopped at sub G1 phase, resulting in DNA damage as well as profound ROS increase. Our results showed that Pd-NPs treatment for 24 hours led to apoptosis, oxidative stress, as well as cell cycle blockage. It is notable that Pd (II) ions induced more severe toxicity. Our findings provide valuable insights on Pd-NPs toxicity. Manuscript profile

Palladium nanoparticles (Pd-NPs) have various applications in industries, such as:Biomedicine, Sewage treatment, Electronics, and Catalytic processes. Differentstudies on NP have shown that they have negative impacts on different cellcategories in vitro. Despite extensive considerations, the molecular mechanismof Pd-NPs toxicity has remained elusive thus far. Therefore, in this paper,we investigated the toxicity of Pd-NPs by evaluating their effects on a humanlymphocyte. Blood lymphocyte cells were initially isolated by ficoll solution andwere exposed to Pd-NPs and Pd (II) ions. Then, we examined oxidative stress, cellcycle, and apoptosis employing flow cytometry. We found the NPs administrationsuppressed cell growth, which in turn resulted in cell apoptosis. Also, the cell cyclestopped at the sub G1 phase, resulting in DNA damage as well as profound ROSincrease. Our results showed that Pd-NPs treatment for 24 hours led to apoptosis,oxidative stress, as well as cell cycle blockage. It is notable that Pd (II) ions inducedmore severe toxicity. Our findings provide valuable insights on Pd-NPs toxicity. Manuscript profile