Key Lab of Food Quality and Safety of Jiangsu Province-State Key Laboratory Breeding Base, Key Laboratory of Control Technology and Standard for Agro-product Safety and Quality, Ministry of Agriculture, Jiangsu Academy of Agricultural Sciences, 210014, Nanjing, Jiangsu, People's Republic of China.
Jiangsu Key Laboratory for Food Quality and Safety-State Key Laboratory Cultivation Base of Ministry of Science and Technology, Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, China.
Mikrochim Acta. 2019 Jan 9;186(2):82. doi: 10.1007/s00604-018-3197-4.
A DNAzyme-based catalytic and stem-loop based amplification scheme is used in a Cu(II)-specific lateral flow assay (LFA). Three test lines with given cut-off value on the test strip are set as the signal indicating zone for semiquantitative analysis by the number of red color bands that appear after lateral flow. The colored bands are generated by accumulation of gold nanoparticles. Four detection ranges can be visualied: (a) 0-2 ng·mL (= negative); 2-50 ng·mL; 50-200 ng·mL and > 200 ng·mL of Cu(II) (= positive). The visual detection limit is thus considered as being 2 ng·mL which is much lower than the U.S. EPA limit in drinking water (1.25 μg·mL). The highly specific DNAzyme, the strong multiple-turnover catalytic target recycling property and highly efficient amplification strategy warrant the high specificity, sensitivity and rapidity of this LFA. Conceivbly, this detecton scheme can be extended to other metal ions by proper choice of the ion-specific DNAzyme. Graphical abstract Schematic presentation of a semiquantitative lateral flow test strip for Cu analysis by three visual cut-off value test lines using catalytic and stem-loop based signal amplification strategy.
基于 DNA 酶的催化和茎环结构的扩增方案用于 Cu(II)特异性侧向流动分析 (LFA)。在测试带上设置了三个具有特定截止值的测试线，作为通过侧向流动后出现的红色色带数量进行半定量分析的信号指示区域。有色带是通过金纳米粒子的积累产生的。可以可视化四个检测范围：(a)0-2ng·mL（=阴性）；50-200ng·mL 和 > 200ng·mL 的 Cu(II)（=阳性）。因此，目视检测限被认为是 2ng·mL，远低于美国环保署在饮用水中的限量（1.25μg·mL）。高度特异性的 DNA 酶、强的多次循环催化目标循环回收特性和高效的扩增策略保证了这种 LFA 的高特异性、灵敏度和快速性。可以想象，通过适当选择离子特异性 DNA 酶，可以将这种检测方案扩展到其他金属离子。
