米糠蛋白碳量子点的表征及应用

Characterization and application of carbon dots from rice bran protein

以米糠蛋白(RBP)为碳源,采用水热合成法制备碳量子点,通过紫外-可见吸收光谱、荧光光谱、高分辨率透射电子显微镜(TEM)、傅里叶变换红外光谱(FTIR)对制备的米糠蛋白碳量子点(RBP-CDs)的光学性能、形貌结构及表面官能团进行表征,并探究RBP-CDs在不同环境下的稳定性及应用于传感、细胞成像、荧光染色等领域的效果。结果表明:RBP-CDs在286 nm下有紫外吸收峰,其发射波长具有激发依赖性;RBP-CDs的形状近似球形,分散性好,尺寸均一,粒径为2~4 nm;RBP-CDs表面富含羟基、羧基,亲水性好;在pH 4~10及不同盐浓度条件下,RBP-CDs的荧光性能良好;在365 nm紫外灯长时间照射下,也表现出良好的光学稳定性,但在不同化学环境中RBP-CDs的荧光强度差别较大,主要与其表面缺陷态有关。荧光传感实验表明,RBP-CDs可作为Fe^(3+)的“Turn-Off”型荧光传感器,检出限可达15.2 nmol/L。RBP-CDs具有较低的细胞毒性,可用于HepG-2细胞的染色成像。RBP-CDs可作为一种新型荧光标记材料,应用于细胞标记和细胞成像领域。

The carbon dots(CDs)were prepared by hydrothermal method using rice bran protein(RBP)as the carbon source.The optical properties,morphology and surface functional groups of the prepared rice bran protein carbon dots(RBP-CDs)were characterized by UV-vis absorption spectrum,fluorescence spectrum,high-resolution transmission electron microscope(TEM)and Fourier transform infrared spectroscopy(FTIR),the stability of RBP-CDs in different environments and their application in sensing,cell imaging and fluorescent staining were investigated.The results showed that RBP-CDs had a UV absorption peak at 286 nm,and its fluorescence emission wavelength was excitation-dependent.RBP-CDs were approximately spherical with good dispersibility and the uniform size,mainly concentrated in 2-4 nm.The surface of RBP-CDs was rich in hydroxyl and carboxyl groups,so the hydrophilic property was better.In the pH 4-10 or high-salt environment,RBP-CDs had good fluorescence performance;under the long-term irradiation of 365 nm ultraviolet lamp,the fluorescence intensity did not change much,showing good optical stability;but the fluorescence intensity was different under different chemical environments,which was mainly related to the defect state of the RBP-CDs surface.The fluorescence sensing experiments showed that the RBP-CDs could be used as a“Turn-Off”fluorescence sensor for Fe;,with a detection limit of 15.2 nmol/L,and it had lower cytotoxicity and could be used for staining and imaging of HepG-2 cells.RBP-CDs could be used as a new type of fluorescent labeling material for the cell labeling and cell imaging.