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Fe3+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 Fe3+, 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.