氨基酸稳定的CdSe纳米晶对溶菌酶进行荧光标记

Application of Aminophenol-stabilized CdSe Nanocrystals as a Fluorescent Label for Lysozyme

利用氨基酸中惟一带有巯基的L-半胱氨酸盐酸盐（L-Cys）作为稳定剂在水相体系中合成CdSe纳米晶,通过表面包覆的L-Cys与生物试剂溶菌酶进行结合,实现CdSe纳米晶对溶菌酶的荧光标记。利用TEM、荧光光谱仪及荧光显微镜等多种手段对样品的结构、形貌及光学性能进行表征。试验结果表明,利用L-Cys为稳定剂合成的CdSe纳米晶具有较强的生物活性,L-Cys本身所带的氨基和羧基可以和多种生物试剂通过不同途径进行结合。对溶菌酶（Lys）标记前后,CdSe纳米晶的发射光谱的峰位发生微小红移,大约为2nm,半峰全宽基本保持不变,在40-50nm之间,荧光强度随所标记的Lys浓度的不同均发生明显增强。所有特性均表明实验所合成的CdSe纳米晶在生物标记方面具有很好的实用价值。

Water-soluble CdSe nanocrystals were synthesized in the system of Na2SeSO3 and Cd （CH2COO）2 by using L-cysteine hydrochloride （L-Cys） as a stabilizer. Lysozyme （Lys） was labelled by the CdSe nanocrystals to investigate the application of CdSe nanocrystals as a fluorescent label which can be connected to the biologic molecule easily by the L-Cys over around the nanocrystals. There are more choice to label the biologic reagents because of the -NH2 and -COOH of Lys. The powder of CdSe nanocrystals was characterized by transmission electron microscopy （TEM） and the optical properties was investigated by fluorescent spectral analysis and fluorescent microscope. It was proved that different CdSe nanocrystals with different sizes and optical properties can be synthesized in different reaction condition. The peak wavelengthes of emission and absorption spectra of the CdSe nanocrystals are at about 530 and 410 nm, respectively. After labeling, the full width at half maximum （FWHM） of CdSe nanocrystals can be kept well which was about 40 nm and easy to distinguish during labeling the biologic reagents. Comparing with the optical properties before labelling, the emission maxima of the obtained CdSe nanocrystals have a little shift, just about 2 nm, but the emission intensity of CdSe nanocrystals-labelled lysozyme can took a great enhancement about 100% with the change of the consistence of Lys. In sum, the L-cys-stabilized CdSe has an important value as a fluorescent label.