## 3 Description of the State of Knowledge
### Toxicity of Silver Nanoparticles  
We can observe that silver nanoparticles accompany us in everyday life in household and biomedical products and possess significant positive properties, including the ability to eliminate pathogenic microorganisms. However, it should be noted that their use also raises concerns about their potential threat to human health and the environment. The toxicity of nanoparticles depends on their size, shape, coating/capping agent, and method of synthesis. Interestingly, it was also noticed that nanoparticles synthesized using the green synthesis method are often more toxic than those synthesized with traditional methods. Toxicity is demonstrated at both the cellular and molecular levels. The major routes of entry of AgNPs are ingestion, inhalation, and dermal contact. Their toxicity is due to the fact that AgNPs are able to induce inflammation and oxidative stress at the site of exposure. In addition to causing oxidative stress, AgNPs also cause a decrease in glutathione levels (GSH) and lipid peroxidation, which in turn leads to DNA damage, apoptosis, and necrosis. Despite numerous toxicological studies, long-term toxicity data are still lacking. However, an occupational respiratory exposure limit value of 0.19 \(\mu\)g/m\({}^{3}\) for AgNPs was recently proposed based on a subchronic inhalation toxicity study in rats [17]. Research using in vitro cell cultures indicates that AgNPs are toxic to several human cell lines (human bronchial epithelial cells, human umbilical vein endothelial cells, red blood cells, human peripheral blood mononuclear cells, immortal human keratinocytes, liver cells). For example, studies on human skin cancer cells (A431) and fibrosarcoma cells (HT-1080) showed that AgNPs (7-20 nm; 6.25 ug/mL; after 24 h of exposure) induced oxidative  
Figure 5: Antifungal mechanisms of silver nanoparticles, based on [35].  
stress in these cells, manifested by a reduced level of GSH and superoxide dismutase (SOD) activity and increased lipid peroxidation. Moreover, they caused the induction of caspase 3 activity and DNA breaks. However, in the case of human colon cancer cells (HT29), hepatoma cells (HepG2), colon cancer cells (HCT116), lung adenocarcinoma cells (A549), lung fibroblasts (IMR-90), and glioma cells (U251), the main cause of toxicity was the generation of reactive oxygen species (ROS). In turn, in the case of mouse embryonic stem cells and mouse embryonic fibroblasts (25 nm; 50 ug/mL; after 72 h of exposure, coated), the increased expression of p53 (cell cycle checkpoint protein), \(\gamma\)-H2 AX (biomarker for DNA double-strand breaks), and Rad 51 (DNA repair protein) was identified. Furthermore, tests conducted in vivo using mice and rats demonstrated that AgNPs can penetrate the blood-brain barrier and accumulate in organs such as the liver, kidneys, and spleen. The induced cytotoxicity, however, largely depends on the size of the nanoparticles, dosage, and duration of exposure [17; 18]. During studies on Sprague-Dawley rats, a negative impact on the liver was observed after the ingestion of AgNPs (60 nm, 300 mg), while prolonged inhalation exposure to AgNPs resulted in lung damage. Additionally, an increased level of silver was found in the offsprings' tissues exposed during the prenatal period. Another consequence of exposure (10 days) was lung inflammation in mice. In in vivo studies on AgNPs in zebrafish, a reduction in the embryo hatching success rate, abnormal dorsal chord, damaged eyes, and curved tail in larvae were observed. The acute toxicity dose for zebrafish was determined to be 40 ug/L for 48 h. AgNPs exhibited cytotoxicity for rainbow trout cell lines and their hepatocytes, and exposure to AgNPs in catfish embryos resulted in mortality, DNA fragmentation, and malformations. Jasmine rice was used as a plant model for studying the toxicity of AgNPs. It was demonstrated that AgNPs, depending on their concentration, can inhibit germination and restrict root growth [101].