Graphene quantum dots (GQDs) have been extensively used in biosensors and bioimaging. Heteroatom-doped GQDs can regulate material properties and endow them to improve structural and physicochemical properties. In this work, N,S-GQDs were prepared through a high-temperature pyrolysis method using L-cysteine and citric acid as the precursors. The morphology and structure of nanocomposites were identified by TEM, X-ray diffractometer (XRD), X-ray photoelectron spectrometer (XPS), and FTIR. The as-prepared N,S-GQDs show bright blue fluorescence with satisfactory fluorescence quantum yield. N,S-GQDs display significant response to riboflavin, achieving a low detection limit of 27nM. The reaction of N,S-GQDs to riboflavin is mainly governed by static quenching. The detection of riboflavin in real samples has been performed to demonstrate its practical application. The obtained N,S-GQDs have low cytotoxicity and have been applied successfully in cell imaging.

中文翻译：

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N,S 共掺杂石墨烯量子点检测核黄素和细胞成像

石墨烯量子点 (GQD) 已广泛用于生物传感器和生物成像。杂原子掺杂的 GQD 可以调节材料特性并赋予它们改善结构和物理化学特性。在这项工作中，以L-半胱氨酸和柠檬酸为前体，通过高温热解法制备了N,S-GQDs。采用TEM、X射线衍射仪(XRD)、X射线光电子能谱仪(XPS)和FTIR对纳米复合材料的形貌和结构进行鉴定。所制备的 N,S-GQD 显示出明亮的蓝色荧光，具有令人满意的荧光量子产率。N,S-GQD 对核黄素有显着响应，检测限低至 27纳米。N,S-GQDs 与核黄素的反应主要受静态猝灭控制。已经对真实样品中的核黄素进行了检测，以证明其实际应用。获得的N,S-GQDs具有低细胞毒性，已成功应用于细胞成像。