柠檬酸荧光碳点的合成及其在Fe(Ⅲ)检测和细胞成像中的应用

Synthesis of Fluorescent Carbon Dots with Citric Acid for Detection of Iron(Ⅲ)and Cell Imaging

以柠檬酸为原料,采用一步水热法合成荧光碳点。所合成的荧光碳点在310nm激发波长下的荧光量子产率为5.3%,发射光谱随着激发波长红移而红移。透射电镜（TEM）表征显示荧光碳点在水溶液中分布均匀,平均粒径为2.9nm。红外（IR）光谱和Zeta电位结果表明碳点表面有羧基和羟基等活性官能团。Fe（Ⅲ）对这些荧光碳点表现出选择性猝灭效果,这种现象可以用于Fe（Ⅲ）检测。在10mmol/L的HEPES缓冲溶液（pH=7.0）中,荧光碳点的荧光强度随着Fe（Ⅲ）浓度的增加逐渐衰减。该方法对Fe（Ⅲ）测定的线性范围为100~500μmol/L,检出限为112.5nmol/L。细胞成像结果表明,柠檬酸的碳点可进入到B16-F10细胞内,并在405nm和488nm激光照射下发出不同颜色的荧光。以上结果表明该碳点在Fe（Ⅲ）检测和细胞成像方面有潜在应用价值。

A one-step hydrothermal method using citric acid as carbon source was developed for the synthesis of fluorescent carbon dots（CDs）.At the excitation wavelength of 310 nm,the quantum yield（QY）of fluorescent CDs is 5.3%.The emission spectra of fluorescent CDs are red-shift along with the bathochromic-shift of excitation wavelength.The as-prepared fluorescent CDs are well dispersed in water,which have an average size of about 2.9nm determined with TEM.FTIR and Zeta potential analysis showed that the fluorescence CDs might contain hydroxyl and carboxyl groups on their surfaces.Fe（Ⅲ）exhibited selective quenching effect to the fluorescent intensity of CDs,which means fluorescent CDs can be used for Fe（Ⅲ）detection.In HEPES buffer（10 mmol/L,pH =7.0）solution,the fluorescence intensity of CDs gradually decreased with Fe（Ⅲ）concentration increasing,and showed a good linear relationship in the range of 100-500μmol/L.The detection limit of this method is 112.5nmol/L.The result of cell imaging incubated with fluorescent CDs indicated that the CDs can penetrate into the B16-F10 cell,and emit multicolor fluorescence under 405 nm and 488 nm laser irradiation.These results revealed that the CDs derived from citric acid might have a potential in Fe（Ⅲ）detection and cell imaging.