Edible and Medicinal Fungi Research Center, Yangtze University, Jingzhou 434025, China.
College of Life Science, Yangtze University, Jingzhou 434025, China.
Sensors (Basel). 2018 Sep 6;18(9):2968. doi: 10.3390/s18092968.
In the past few years, melamine has been illegally added into dairy products to increase the apparent crude protein levels. If humans or animals drink the milk adulteration of melamine, it can form insoluble melamine⁻cyanurate crystals in their kidneys which causes kidney damage or even death. In the present work, we constructed a simple and label-free fluorescent method for melamine detection based on melamine-thymine recognition. SYBR Green I was utilized as a reporter for this method as it did not require any modification or expensive equipment. In the absence of melamine, polythymine DNA was digested by Exo I, which caused a decrease in the fluorescence signal. In the presence of melamine, the polythymine DNA was able to fold into a double chain structure, however this was done with the help of T-melamine-T mismatches to prevent degradation. Then, the SYBR Green I combined with the double-stranded DNA to result in an intense fluorescence signal. The limit of detection in this method was 1.58 μM, which satisfied the FDA standards. This method also had a good linear relationship within the range of 10⁻200 μM. In addition, this new method has a good selectivity to distinguish melamine from the component of milk. As a result, we developed a simple and highly selectivity method for melamine detection.
在过去的几年中，三聚氰胺被非法添加到乳制品中以提高表观粗蛋白水平。如果人类或动物饮用三聚氰胺掺杂的牛奶，三聚氰胺会在肾脏中形成不溶性的三聚氰胺-尿酸晶体，从而导致肾脏损伤甚至死亡。在本工作中，我们构建了一种基于三聚氰胺-胸腺嘧啶识别的简单、无标记的荧光三聚氰胺检测方法。我们利用 SYBR Green I 作为报告分子，因为它不需要任何修饰或昂贵的设备。在没有三聚氰胺的情况下，Exo I 会消化多聚胸腺嘧啶 DNA，导致荧光信号减弱。在存在三聚氰胺的情况下，多聚胸腺嘧啶 DNA 能够折叠成双链结构，但这是借助 T-三聚氰胺-T 错配来完成的，以防止降解。然后，SYBR Green I 与双链 DNA 结合，产生强烈的荧光信号。该方法的检测限为 1.58 μM，满足 FDA 标准。该方法在 10-200 μM 范围内也具有良好的线性关系。此外，该新方法对三聚氰胺与牛奶成分具有良好的选择性。因此，我们开发了一种简单、高选择性的三聚氰胺检测方法。
