This study investigates the biocompatibility of graphene oxide (GO) by examining its effects on human fibroblast cells and mice. GO was synthesized using the modified Hummers method and characterized using transmission electron microscopy (TEM), atomic force microscopy (AFM), and Fourier transform infrared (FT-IR) spectroscopy. Human fibroblast cells were exposed to varying concentrations of GO (5–100 μg/mL) for 1–5 days, and the cell survival rate was measured using the CCK8 assay. Results showed that GO concentrations below 20 μg/mL did not exhibit toxicity, while concentrations above 50 μg/mL caused significant cytotoxicity, including decreased cell adhesion, apoptosis, and intracellular accumulation in lysosomes, mitochondria, endoplasm, and the nucleus. In mice, three groups were tested with low (0.1 mg), medium (0.25 mg), and high (0.4 mg) doses of GO, with a control group. Mice in the high-dose group exhibited chronic toxicity, including 4/9 deaths and lung granuloma formation, primarily in the lungs, liver, spleen, and kidneys. GO was found to accumulate in these organs, with the kidneys being unable to effectively eliminate it. The study suggests that GO's toxicity is dose-dependent and that its long-term presence in the kidneys may limit its application in biomedical contexts. The mechanisms of GO toxicity include its ability to bind to cell surfaces, triggering intracellular signaling pathways that lead to decreased adhesion and apoptosis. In mice, GO enters the bloodstream and is distributed to the lungs, liver, spleen, and kidneys, where it can cause inflammation and granuloma formation. The blood-brain barrier prevents GO from reaching the brain, and its physical shape makes it difficult to be excreted via the kidneys, leading to long-term accumulation in the liver, spleen, and kidneys. The study concludes that GO exhibits dose-dependent toxicity to both cells and animals, with potential applications in biomedical engineering requiring careful consideration of its biocompatibility. Further research is needed to understand the interaction between GO and immune cells in vivo.This study investigates the biocompatibility of graphene oxide (GO) by examining its effects on human fibroblast cells and mice. GO was synthesized using the modified Hummers method and characterized using transmission electron microscopy (TEM), atomic force microscopy (AFM), and Fourier transform infrared (FT-IR) spectroscopy. Human fibroblast cells were exposed to varying concentrations of GO (5–100 μg/mL) for 1–5 days, and the cell survival rate was measured using the CCK8 assay. Results showed that GO concentrations below 20 μg/mL did not exhibit toxicity, while concentrations above 50 μg/mL caused significant cytotoxicity, including decreased cell adhesion, apoptosis, and intracellular accumulation in lysosomes, mitochondria, endoplasm, and the nucleus. In mice, three groups were tested with low (0.1 mg), medium (0.25 mg), and high (0.4 mg) doses of GO, with a control group. Mice in the high-dose group exhibited chronic toxicity, including 4/9 deaths and lung granuloma formation, primarily in the lungs, liver, spleen, and kidneys. GO was found to accumulate in these organs, with the kidneys being unable to effectively eliminate it. The study suggests that GO's toxicity is dose-dependent and that its long-term presence in the kidneys may limit its application in biomedical contexts. The mechanisms of GO toxicity include its ability to bind to cell surfaces, triggering intracellular signaling pathways that lead to decreased adhesion and apoptosis. In mice, GO enters the bloodstream and is distributed to the lungs, liver, spleen, and kidneys, where it can cause inflammation and granuloma formation. The blood-brain barrier prevents GO from reaching the brain, and its physical shape makes it difficult to be excreted via the kidneys, leading to long-term accumulation in the liver, spleen, and kidneys. The study concludes that GO exhibits dose-dependent toxicity to both cells and animals, with potential applications in biomedical engineering requiring careful consideration of its biocompatibility. Further research is needed to understand the interaction between GO and immune cells in vivo.