Due to the diverse applications, graphene-family nanomaterials (GFNs) have a high probability of release into the aquatic system, potentially posing risks to the aquatic environment. The acute effects on single-celled Microcystis aeruginosa by graphene oxide (GO) or graphene oxide quantum dots (GOQDs) were compared in the present study. GOQDs dispersed more effectively in water than GO at all pH values tested. The 96-hour median effective concentration (EC₅₀) of GO and GOQDs were determined to be 49.32 and 22.46 mg/L, respectively. Both GO and GOQDs were internalized by heteroagglomeration and envelopment processes, with GOQDs inducing stronger upregulation of cell permeability, plasmolysis and lipid bodies than GO. Cracking of thylakoid layers, disappearance of nucleoid, and disintegration of cell infrastructure were observed at higher concentrations. In comparison to GO, GOQDs induced higher reactive oxygen species (ROS) and malondialdehyde (MDA) and disrupted antioxidant enzymes, leading to the inhibition of cellular contents such as chlorophyll a and proteins. Furthermore, both GO and GOQDs adsorbed nutrients from the algal medium, resulting in nutrient depletion-induced indirect toxicity, with GOQDs depleting more nutrients than GO. The current study provides new understanding of nanotoxicity of GO and GOQD and aids in the potential risks of nanomaterials in aquatic environments.

由于应用广泛，石墨烯家族纳米材料 (GFN) 极有可能释放到水生系统中，可能对水生环境构成风险。本研究比较了氧化石墨烯 (GO) 或氧化石墨烯量子点 (GOQDs)对单细胞铜绿微囊藻的急性影响。在所有测试的 pH 值下，GOQD 比 GO 更有效地分散在水中。96 小时中位有效浓度 (EC ₅₀) 的 GO 和 GOQD 分别测定为 49.32 和 22.46 mg/L。GO 和 GOQDs 都通过异质聚集和包络过程内化，GOQDs 比 GO 诱导更强的细胞通透性、质壁分离和脂质体上调。在较高浓度下观察到类囊体层破裂、类核消失和细胞基础结构解体。与 GO 相比，GOQDs 诱导更高的活性氧 (ROS) 和丙二醛 (MDA) 并破坏抗氧化酶，导致叶绿素 a 和蛋白质等细胞内容物受到抑制。此外，GO 和 GOQDs 都从藻类培养基中吸附养分，导致养分消耗引起的间接毒性，GOQDs 比 GO 消耗更多的养分。