Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science &Nutritional Engineering, China Agricultural University, Beijing 100083, China.
Beijing Laboratory for Food Quality and Safety, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China.
Sci Rep. 2017 Mar 7;7:43362. doi: 10.1038/srep43362.
To solve the requirement of on-site, rapid, and visual detection of copper (II) (Cu) in aqueous solution, a turn-off sensor for detecting copper (II) ion was developed based on Cu-dependent DNAzyme as the recognition element and hybridization chain reaction (HCR)-based horseradish peroxidase (HRP) concatemers as the signal amplifier and the signal report element. The detection unit, which was composed of the immobilized Cu-dependent DNAzyme coupled with HCR-based HRP concatemers via Waston-Crick base pairing, could catalyze hydrogen peroxide (HO) via TMB, generating obvious green color and turning yellow after sulfuric acid termination with optical absorption at 450 nm. Upon Cu addition, the substrate strand of the Cu-dependent DNAzyme concatenated with the HCR-based HRP complex was irreversibly cleaved, efficiently causing dramatic reduction of the detection signal. Under optimal conditions, the detection signal decreased with the concentration of Cu in 5 min, exhibiting a linear calibration from 0.05 to 3 μM with a detection limit of 8 nM. The sensor also displayed a high selectivity for Cu given the specificity and anti-interference of the detection unit, and this system was applicable for monitoring Cu in real water samples. Generally speaking, the proposed sensor exhibits good potential in environment surveys.
为了解决现场、快速和可视化检测水溶液中铜（II）（Cu）的需求，开发了一种基于 Cu 依赖性 DNA 酶作为识别元件、基于杂交链式反应（HCR）的辣根过氧化物酶（HRP）串联体作为信号放大器和信号报告元件的 Cu(II)离子关闭传感器。检测单元由固定化的 Cu 依赖性 DNA 酶与基于 HCR 的 HRP 串联体通过 Watson-Crick 碱基配对偶联而成，能够通过 TMB 催化过氧化氢（HO）生成明显的绿色，硫酸终止后变黄，在 450nm 处具有光学吸收。加入 Cu 后，Cu 依赖性 DNA 酶与基于 HCR 的 HRP 复合物的底物链被不可逆地切割，有效地导致检测信号的急剧减少。在最佳条件下，检测信号在 5 分钟内随 Cu 浓度的变化而降低，在 0.05 至 3 μM 范围内呈现线性校准，检测限为 8 nM。鉴于检测单元的特异性和抗干扰性，该传感器对 Cu 具有较高的选择性，该系统可用于监测实际水样中的 Cu。总的来说，该传感器在环境调查中具有良好的应用前景。
