氮掺杂高量子产率荧光碳点的制备及其体外生物成像研究

为获得高量子产率的碳点,以柠檬酸为碳源,苯二胺的3种同分异构体为氮源,采用两步溶剂热法制备了氮掺杂荧光碳点。利用透射电子显微镜(TEM)、紫外-可见吸收光谱(UV-Vis)、荧光光谱、红外光谱(FTIR)、X射线光电子能谱(XPS)对样品进行表征,并考察了碳点的细胞毒性和体外生物成像。实验结果表明:3种高量子产率碳点(Y=52%,60.4%,53.2%)的粒径均一,具有较好的分散性,平均尺寸分别为4.5,5.3,5.2 nm。碳点表面含有羟基、羧基、胺基等基团,在紫外光激发下均能发出明亮的蓝色荧光,并具有稳定的荧光性能。细胞实验表明:3种碳点具有较好的生物相容性,能够快速进入细胞并成功应用于细胞的荧光成像。

Preparation of N-doped Fluorescent Carbon Dots with High Quantum Yield for In-vitro Bioimaging

In order to obtain carbon dots with high quantum yield, a simple two-step solvothermal method was used to prepare fluorescent N-doped carbon dots with citric acid as carbon source and three isomers of phenylenediamine as nitrogen source. The carbon dots were characterized by Trans-mission electron microscopy ( TEM) , ultraviolet-visible spectrophotometry ( UV-Vis) , fluorescence spectrophotometry, Fourier transform infrared spectra ( FTIR ) , X-ray photoelectron spectroscopy ( XPS) , followed by studying the cytotoxicity and in-vitro bioimaging. The results show that three kinds of high quantum yield carbon dots ( Y=52%, 60 . 4% and 53 . 2%) possessing uniform size and excellent dispersibility have been successfully prepared, and the average size is 4. 5, 5. 3, 5. 2 nm. The prepared carbon dots with hydroxyl, carboxyl, amine and other groups on the surface can emit bright blue fluorescence under the excitation of ultraviolet light, holding favorable optical stabil-ity at the same time. In addition, the cell imaging experiments indicate that the three kinds of carbon dots have good biocompatibility, capable of rapidly entering cells and successfully applied to fluorescence imaging of cells.