茯苓多糖衍生碳点的细胞行为学研究

Cellular behavior of carbon dots derived from Poria cocos polysaccharide

碳点的生物学行为,特别是关于细胞摄取和细胞内分布机制研究,是其生物医学应用的基础。本研究以茯苓多糖为原料,采用水热法合成了蓝色荧光碳量子点,探索碳点进入细胞的具体生物学行为,以评估其生物学活性。利用透射电子显微镜、紫外-可见吸收光谱、荧光光谱、傅里叶变换红外光谱、X射线衍射和X射线光电子能谱对其进行了表征;以免疫细胞-RAW264.7细胞(小鼠单核巨噬细胞)和癌细胞-4T1细胞(小鼠乳腺癌细胞)这两种不同的细胞系为研究对象,研究茯苓多糖碳点在细胞内的摄取动力学过程及其摄取途径、分布和外排等过程。研究结果显示,茯苓多糖衍生碳点的粒径分布范围为2~10 nm,平均粒径为6.85 nm,主要由C、O和N元素组成,具有-OH、C=O、C-N、C=C等丰富的表面官能团,荧光量子产率为4.72%。碳点进入细胞可呈现出一定的浓度和时间依赖性,不同的细胞系,摄取内吞途径不一。在RAW264.7细胞内主要以巨噬细胞特有的吞噬作用摄取进入细胞内,少部分通过小窝蛋白介导的内吞作用,而对于4T1细胞主要是通过网格蛋白介导的内吞作用和巨胞饮过程。综上,合成的中药衍生碳点具有良好的荧光特性、低细胞毒性和优异的生物相容性,可用于细胞成像应用研究。

The biological behavior of carbon dots,especially the mechanism of cellular uptake and intracellular distribution,is the basis of its biomedical applications.In this paper,blue fluorescent carbon quantum dots were synthesized by hydrothermal method with Poria cocos polysaccharide as raw material,and the specific biological behavior of carbon dots entering cells was explored to evaluate its biological activity.It was characterized by transmission electron microscopy,UV-vis absorption spectroscopy,fluorescence spectroscopy,Fourier transform infrared spectroscopy,X-ray diffraction and X-ray photoelectron spectroscopy.Two different cell lines,immunocytesRAW264.7 cells(mouse mononuclear macrophages cells) and cancer cells-4T1cells(mouse breast cancer cells),were used as the research objects to study the uptake kinetics,uptake pathway,distribution and efflux of polysaccharide carbon dots in cells.The results showed that the carbon dots have a size distribution of 2 to 10 nm,and the average size was 6.85 nm.The carbon dots were mainly composed of C,O and N elements,with abundant surface functional groups such as-OH,C=O,C-N and C=C,and the fluorescence quantum yield was 4.72%.Carbon dots enter cells in a certain concentration and time dependence.Different cell lines have different uptake pathways.RAW264.7 cells enter the cells mainly by macrophage-specific phagocytosis,and a small part of the endocytosis is mediated by caveolin,while 4T1cells are mainly mediated by grid protein endocytosis and giant cell drinking process.In summary,the synthesized carbon dots have good fluorescence properties,low cytotoxicity and excellent biocompatibility,which can be used for cell imaging applications.