The toxicity of nanoparticles in a biological system is an integration of effects arising from surface functionality, particle size, ionic dissolution, etc. This complexity suggests that generalization of a material’s toxicity may be inappropriate. Moreover, from a medicinal point of view, toxicity can be used for treatment of malignant cells, such as cancer. In this study, highly biocompatible carbon nanodots (gCDs) were synthesized by reacting citric acid and urea in glycerol, which resulted in abundant hydroxyl functional groups on the particle surface. gCDs show excitation-dependent photoluminescence but with bright green to yellow emission. Importantly, a series of toxicity assessments showed that as-synthesized gCDs possessed exceptional biocompatibilities to various biological entities including 18 bacteria species, Petunia axillaris seedlings, and Artemia franciscana nauplii. Furthermore, the particles were shown to have low to no toxic effects on human embryonic kidney (HEK-293), breast (MCF-7), and oral squamous (CAL-27) carcinoma cell lines. Of particular interest, the gCDs displayed antiproliferative activities against ovarian choriocarcinoma cells (JAr/Jeg-3 cell lines), which may be further explored for cancer drug discovery.

中文翻译：

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富含羟基的碳纳米点对癌症研究的选择性毒性

纳米粒子在生物系统中的毒性是由表面功能，粒径，离子溶解等产生的作用的综合。这种复杂性表明，材料毒性的一般化可能是不合适的。而且，从医学的观点来看，毒性可以用于治疗恶性细胞，例如癌症。在这项研究中，通过柠檬酸和尿素在甘油中的反应合成了具有高度生物相容性的碳纳米点（gCD），从而在颗粒表面产生了丰富的羟基官能团。gCDs显示出与激发有关的光致发光，但发射出绿色至黄色的亮光。重要的是，一系列毒性评估表明，合成后的gCD对包括18种细菌在内的各种生物实体具有卓越的生物相容性，矮牵牛的幼苗，和非洲蒿的无节幼体。此外，显示该颗粒对人胚胎肾脏（HEK-293），乳腺癌（MCF-7）和口腔鳞状（CAL-27）癌细胞系具有低至无毒性作用。特别令人感兴趣的是，gCD对卵巢绒毛膜癌细胞（JAr / Jeg-3细胞系）显示出抗增殖活性，可以进一步探索其用于癌症药物的发现。