A standard procedure for rapid toxicity evaluation of carbon dots both in vitro and in vivo

Carbon dots (CDs) are an emerging class of fluorescent quantum dot nanomaterials that have attracted considerable scientific attention for biomedical or bioimaging applications due to their physicochemical and biochemical properties. With the emergence of massive novel synthetic CDs applying to biomedical fields of science, evaluating their biosafety before any biological application is essential. However, there is no universal protocol or routine procedures for toxicity detection and biosafety assessment of CDs in general biological environments. Herein, we provide an ideal and fast operating system to detect the biotoxicity of CDs, which has been preliminary practiced. Briefly, the obtained CDs will be evaluated by in vitro cytotoxicity assay using cell counting kit-8, lactate dehydrogenase assay kit, and flow cytometry. Meanwhile, the model creature zebrafish is employed to perform in vivo evaluation by measuring body length, hatching rate, heart rate, and morphological observation. Our operating procedure condenses previous scattered biosafety detection methods into a rapid standard evaluation protocol that can be applied to early biotoxicity screening of CDs. This protocol will accelerate CDs biological exploitation and guide future industrialized biosafety assessment in large-scale applications.