碳点（CDs）或CDs /聚合物复合材料已应用于许多领域。在这里，通过蛋黄的碳化合成了新颖的碳点，并通过TEM，FTIR，XPS和光致发光光谱进行表征。碳点发现近似球形，平均尺寸为4.46±1.17 nm，并且在紫外线照射下发出明亮的蓝色光致发光。CD的光致发光在0.05-0.45 mM范围内被Fe3 +选择性猝灭，意味着它们可以用于溶液中的Fe3 +检测。此外，CDs可以被HepG2细胞吸收，以展示明亮的蓝色光致发光。强度可以反映细胞内Fe3 +的水平，表明它们可以用于细胞成像和细胞内Fe3 +监测。接下来，多巴胺在CDs表面聚合形成了聚多巴胺（PDA）包被碳点（CDs@PDA）。我们发现PDA涂层可以通过内滤效应猝灭CDs的光致发光，猝灭程度与DA浓度（Log CDA）的对数成线性关系。另外，选择性实验表明该方法具有对许多可能的干扰物质的高选择性。这表明CDs与Tris缓冲液结合后可潜在地作为多巴胺的分析试剂盒。最后，CDs@PDA表现出优异的光热转换能力，在近红外激光照射下可以有效地杀死HepG2细胞。总体而言，本研究中的CDs和CDs@PDA展示了许多优异的优势，并且潜在用于多种应用，例如溶液中和细胞中的Fe3 +传感器，细胞成像，多巴胺检测试剂盒，以及癌症治疗的光热剂。 © 2023. The Author(s).

Carbon dots (CDs) or CDs/polymer composites have been applied in numerous fields. Here, novel CDs were synthesized by carbonization of egg yolk, and characterized by TEM, FTIR, XPS and photoluminescence spectra. The CDs were found to be approximate sphere in shape with an average size of 4.46 ± 1.17 nm, and emitted bright blue photoluminescence under UV irradiation. The photoluminescence of CDs was found selectively quenched by Fe3+ in a linear manner in the range of 0.05-0.45 mM, meaning they could be applied for Fe3+ detection in solution. Moreover, the CDs could be uptaken by HepG2 cells to exhibit bright blue photoluminescence. The intensity could reflect the level of intracellular Fe3+, indicating they could be further used for cell imaging and intracellular Fe3+ monitoring. Next, dopamine was polymerized on the surface of CDs to obtain the polydopamine (PDA)-coated CDs (CDs@PDA). We found PDA coating could quench the photoluminescence of CDs via inner filter effect, and the degree of quenching was linearly related to the logarithm of DA concentration (Log CDA). Also, the selectivity experiment indicated the method had a high selectivity for DA over a number of possible interfering species. This indicated the CDs in combination with Tris buffer could be potentially applied as the assay kit of dopamine. At last, the CDs@PDA exhibited excellent photothermal conversion capability, and they could efficiently kill HepG2 cells under NIR laser irradiation. Overall, the CDs and CDs@PDA in this work exhibited many excellent advantages, and could be potentially used for multi-applications, such as Fe3+ sensor in solution and cellular, cell imaging, dopamine assay kit, as well as photothermal agents for cancer therapy.© 2023. The Author(s).