Key Lab of Analysis and Detection for Food Safety of Ministry of Education, Fujian Provincial Key Lab of Analysis and Detection for Food Safety, College of Chemistry, Fuzhou University, Fuzhou, Fujian 350116, China; College of Pharmacy, Fujian University of Traditional Chinese Medicine, Fuzhou, Fujian 350122, China.
Key Lab of Analysis and Detection for Food Safety of Ministry of Education, Fujian Provincial Key Lab of Analysis and Detection for Food Safety, College of Chemistry, Fuzhou University, Fuzhou, Fujian 350116, China.
Anal Chim Acta. 2017 Mar 1;956:63-69. doi: 10.1016/j.aca.2016.12.021. Epub 2016 Dec 27.
A novel colorimetric biosensor, which employs DNAzyme-functionalized magnetic beads (MBs) as recognition probe, enzyme-assisted catalytic oxidation of TMB (3,3',5,5'-tetramethylbenzidine sulfate) as signal and DNA hybridization chain reaction as amplification strategy, has been developed for detecting trace uranyl ion (UO) in seafood and aqueous environment with high sensitivity and specificity. We demonstrated that UO can specifically cleave DNAzyme immobilized on MBs surface to release a short single-strand DNA (primer), and the released primer trigger DNA hybridization chain reaction to form a long one dimensional DNA concatamer on the MBs surface. The resulting long DNA concatamer could capture a large amount of HRP to generate the one UO-to-multiple HRP amplification effect. Upon the addition of TMB-HO solution, the HRP-tagged DNA concatamer-MBs conjugates could catalyze the HO-mediated oxidation of TMB, and thus results in a color change from colorless to blue in solution. This provided a sensitive and selective sensing platform for the visual or colorimetric detection of UO. The proposed biosensor has high sensitivity and strong anti-interference capability, it can be used to detect as low as 2.5 ppb (9.25 nM) of UO by naked-eye observation and 0.09 ppb (0.33 nM) of UO by UV-visible spectrometry with no interference of other ions and a RSD ≤ 6% (n = 5). With the help of this method, we have successfully determined trace UO in fish muscle and river water with a recovery of 93-106%. High sensitivity and specificity, as well operation convenience, low cost and strong resistibility to the matrix, which makes our method a potential approach for the on-site detection of UO in seafood and aqueous environment.
一种新型比色生物传感器，采用 DNA 酶功能化磁性珠（MBs）作为识别探针，酶辅助 TMB（硫酸 3,3',5,5'-四甲基联苯胺）的催化氧化作为信号，DNA 杂交链式反应作为扩增策略，已被开发用于检测痕量海产食品和水环中的铀酰离子（UO），具有高灵敏度和特异性。我们证明 UO 可以特异性地切割固定在 MBs 表面的 DNA 酶以释放短的单链 DNA（引物），并且释放的引物触发 DNA 杂交链式反应以在 MBs 表面上形成长的一维 DNA 连接体。所得长 DNA 连接体可以捕获大量 HRP 以产生一个 UO 到多个 HRP 的扩增效果。加入 TMB-HO 溶液后，HRP 标记的 DNA 连接体-MBs 缀合物可以催化 HO 介导的 TMB 氧化，从而导致溶液从无色变为蓝色的颜色变化。这为 UO 的目视或比色检测提供了一个灵敏且选择性的传感平台。所提出的生物传感器具有高灵敏度和强抗干扰能力，通过肉眼观察可以检测低至 2.5 ppb（9.25 nM）的 UO，通过紫外可见光谱可以检测低至 0.09 ppb（0.33 nM）的 UO，且不受其他离子的干扰，RSD≤6%（n=5）。借助该方法，我们成功地测定了鱼肌肉和河水中的痕量 UO，回收率为 93-106%。高灵敏度和特异性，以及操作方便、低成本和对基质的强抵抗力，使我们的方法成为海产食品和水环中 UO 的现场检测的一种潜在方法。
