新型水溶性多色荧光碳点的制备及细胞成像研究

Preparation of Novel Water Soluble Multicolor Carbon Dots for Cell Imaging

以鸡蛋清和牛奶分别与葡萄糖进行水热反应,制备水溶性多色荧光碳点,通过膜和柱层析分离纯化,利用透射电子显微镜（TEM）、紫外吸收光谱（UV）、荧光光谱（FL）、红外光谱（FTIR）等技术对所制备碳纳米粒子的粒径大小、吸收光谱、发光性质、表面基团进行表征.将所制备的碳点与小鼠黑色素瘤细胞共孵育,进行细胞成像应用评价.结果表明：制备的两种水溶性荧光碳点平均粒径分别为2.5 nm和4.9 nm,可在紫外灯下发出明亮的荧光,紫外最大吸收波长为250 nm.基于鸡蛋清或牛奶与葡萄糖反应制备的多色荧光碳量子点具有良好水溶性,其荧光光谱最大发射波长分别在410 nm和400nm处,同时在660～800 nm激发波长范围内具有上转换性质,且荧光发射光谱随着激发光波长的增加发生红移.红外光谱表明存在—COOH、-NH2和-OH基团.细胞成像结果表明,在405 nm或488 nm激光照射下,所制备的碳点在细胞内的荧光成像清晰可见,而且在碳点浓度小于2.5 mg/mL时,均表现出较低的细胞毒性.

Two types of water-soluble multicolor carbon dots（CDs） were prepared through the reac- tions of egg white or milk with glucose by hydrothermal method. The CDs derived from egg white2glu- cose （E -CDs） and milk/glucose （M -CDs） were purified by filtering membrane and column chroma- tography. Particle sizes, UV - vis absorption and emission spectra and surface groups of the two types of CDs were characterized using transmission electron microscopy （TEM）, ultraviolet spectrome- try （ UV ）, fluorescence spectroscopy （ FL）, Fourier transform infrared spectroscopy （ FTIR ） tech- niques, and their muhicolor cell imaging were evaluated by incubation with mouse melanoma cells. The results showed that the two types of multicolor CDs prepared by hydrothermal method were highly water-soluble with particles sizes of 2. 5 nm and 4. 9 nm, respectively, which could emit bright mul- ticolor fluorescence under the excitation of UV - vis light. Their maximum absorption wavelength was 250 nm, whereas the maximum fluorescence emission wavelengths were located at 410 nm and 400 nm for E - CDs and M - CDs, respectively. Meanwhile, the obtained CDs exhibited upconversion fluorescence properties in the excitation wavelength range of 660 - 800 nm. The emission peak posi- tions from both CDs shifted to longer wavelengths, and the intensity gradually decreased with the in- crease of excitation wavelengths. FTIR spectra analysis revealed the presence of --COOH, --NH2 and --OH on both of CDs＇ surface. Cell imaging results demonstrated that fluorescence in the ceils cultured with CDs was clearly visible under 405 nm and 488 nm laser irradiation, respectively, and both of the CDs showed very low cytotoxicity when the CDs＇ concentration was less than 2. 5 mg/mL.