基于胸腺嘧啶-三聚氰胺-胸腺嘧啶结构和SYBR Green Ⅰ荧光检测牛奶中三聚氰胺

摘要

基于胸腺嘧啶( T)-三聚氰胺-T特异性结构,建立了SYBR Green Ⅰ荧光均相检测三聚氰胺的方法。三聚氰胺不存在时,SYBR Green Ⅰ与聚T单链DNA结合较弱,荧光信号较弱；三聚氰胺存在时,聚T单链DNA通过T-三聚氰胺-T错配形成折叠结构。 SYBR Green Ⅰ嵌入双链DNA的双螺旋结构中,释放出强荧光信号。结果表明,三聚氰胺浓度在0.1~10μmol/L范围内呈良好的线性关系,检出限为35 nmol/L。本方法简单、快速、成本低、灵敏度高。%A novel fluorescence homogeneous biosensing strategy was developed for simple, rapid and sensitive detection of melamine in milk by using the polythymine oligonucleotide T24 and SYBR Green Ⅰ. In the absence of melamine, the fluorescence of SYBR Green Ⅰ was weak. The interactions between the single strand oligonucleotide T24 and SYBR Green Ⅰ were weak. In contrast, the presence of melamine drove the formation of T-melamine-T folded structure and enabled the SYBR Green Ⅰ to intercalate into double-strand DNA, resulting in the enhancement of fluorescence intensity. The results revealed that the method allowed a sensitive, simple, and rapid assay of melamine with a linear response range from 0. 1 μmol/L to 10 μmol/L and a detection limit of 35 nmol/L.