A facile, environmentally friendly one-step reaction for the preparation of luminescent N-doped graphene quantum dots (GQDs) involving a hydrothermal reaction between citric acid and 2-aminoethylphosphonic acid has been designed. Graphene quantum dots have been characterized by UV-visible absorption, FTIR spectroscopy, transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX) and dynamic light scattering (DLS) techniques. Furthermore, the biological activity of the GQDs has been studied. UV-visible spectroscopy studies of the interactions between the GQDs and calf thymus DNA (CT-DNA) showed that the compound interacts with CT-DNA via intercalative binding. DNA cleavage study showed that the GQDs cleaved DNA oxidatively. In addition, antioxidant activity of N-doped GQDs was measured using the DPPH method. As the concentration of the compound increased, the antioxidant activity also has increased. According to cell viability analyses results, the N-doped GQDs showed cell viability (70%) when the concentration reaches 228 μg/mL for A549, 200 μg/mL for MDA-MB-231 and 140 μg/mL for NIH-3T3 cell lines with 24 h incubation.

中文翻译：

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2-氨基乙基膦酸官能化的石墨烯量子点的合成与表征：生物活性，抗氧化活性和细胞活力

设计了一种简便，环保的一步法制备发光的N掺杂石墨烯量子点（GQD），涉及柠檬酸和2-氨基乙基膦酸之间的水热反应。石墨烯量子点的特征在于紫外可见吸收，FTIR光谱，透射电子显微镜（TEM），能量色散X射线光谱（EDX）和动态光散射（DLS）技术。此外，已经研究了GQD的生物学活性。GQD与小牛胸腺DNA（CT-DNA）之间相互作用的紫外可见光谱研究表明，该化合物通过插入结合与CT-DNA相互作用。DNA裂解研究表明，GQDs氧化裂解DNA。另外，使用DPPH方法测量了N掺杂的GQD的抗氧化活性。随着化合物浓度的增加，抗氧化剂活性也增加。根据细胞活力分析结果，当A549的浓度达到228μg/ mL，MDA-MB-231的浓度为200μg/ mL和NIH-3T3细胞的浓度为140μg/ mL时，N掺杂的GQD表现出细胞活力（70％）。孵化24小时。