CdSe量子点探针共振光散射法检测溶菌酶

Resonance Light Scattering Method for the Determinaiton of Lysozyme Using CdSe Quantum Dots as Probe

基于CdSe量子点与溶菌酶之间的相互作用，采用共振光散射法建立了简单快速检测溶菌酶的新方法．在优化的实验条件下，当溶菌酶浓度在0．01-0．8μmol／L范围内变化时，散射光强度与溶菌酶浓度间呈现良好的线性关系，相关系数为0．9960．此方法对溶菌酶的检出限为5．2nmol／L，对0．09μmol／L溶菌酶5次平行测定的相对标准偏差为2．1％，此方法选择性较好，常见离子、蛋白质及常见氨基酸对溶菌酶检测干扰较小，这种新方法已被用于合成样品中溶菌酶的检测，并取得较好结果．为进一步考察CdSe量子点与溶菌酶之间的相互作用，进行了圆二色光谱、透射电子显微镜和荧光寿命表征研究，结果表明，CdSe量子点与溶菌酶的结合不仅使溶菌酶的构象发生变化，也使CdSe量子点的分散状态和荧光寿命发生了改变．

A simple and rapid method for lysozyme determination was developed based on the interaction between CdSe quantum dots and lysozyme. Under the optimized conditions, the linear range of resonance light scattering intensity versus the concentration of lysozyme was 0.01-0. 8μmol/L, with a correlation coefficient of 0. 9960. The limit of detection of lysozyme of this method was 5.2 nmol/L. The relative standard deviation for 0.09 μmol/L lysozyme was 2. 1% （ n = 5 ）. The proposed method possessed the advantage of specificity. There was no interference to coexisting foreign substances including common ions, proteins and common amino acids. The synthetic samples were analyzed by the methodology and the results were satisfying. The proposed method has been applied to the determination of lysozyme in synthetic samples. The interaction between CdSe quantum dots and lysozyme was further investigated by using circular dichroism, TEM and fluorescent lifetime. These results indicated that the interaction between CdSe quantum dtos and lysozyme not only resulted in the change of the lysozyme conformation, but also led to the variations of the dispersibility and fluorescent lifetime of CdSe quantum dots.