State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China; School of Food Science and Technology, Jiangnan University, Wuxi 214122, China; International Joint Laboratory on Food Safety, Jiangnan University, Wuxi 214122, China.
School of Food Science and Technology, Jiangnan University, Wuxi 214122, China.
Spectrochim Acta A Mol Biomol Spectrosc. 2020 Jan 5;224:117387. doi: 10.1016/j.saa.2019.117387. Epub 2019 Jul 20.
Techniques that are sensitive to detect mercury ion (Hg) are very important, due to its serious threat to public health and food security. In this work, a colorimetric aptasensor was fabricated for the detection of Hg based on rolling circle amplification (RCA). The aptamer was immobilized onto the microplate and hybridized with its complementary strand (cDNA) which linked with a primer for triggering the RCA reaction of circular template. The successfully RCA process led to the formation of long ssDNA chains on the microplate, which created many hybridized DNA fragments for bio-cDNA. The tagged amount of horseradish peroxidase (HRP) was enhanced through the avidin/biotin binding between avi-HRP and bio-cDNA. In the addition of TMB-HO, HRP was catalyzed and generated an optical signal. However, in the presence of target, Hg specifically and preferentially bound with aptamer and formed a strong and stable T-Hg-T complex, which led to the release of cDNA and HRP cluster. Consequently, the optical signal decreased. Our results showed that the limit of detection (LOD) of this system was 1.6 nM with excellent specificity, and that the detection signals were enhanced by up to 18 times under RCA conditions when compared with detections without RCA. This method has been successfully used to detect Hg in water samples with a recovery of 98%-105.74%.
由于汞离子 (Hg) 对公众健康和食品安全构成严重威胁，因此能够灵敏检测汞离子的技术非常重要。在这项工作中，我们基于滚环扩增 (RCA) 构建了用于检测 Hg 的比色适体传感器。将适体固定在微孔板上，并与与其互补的链 (cDNA) 杂交，该 cDNA 与引物相连，用于触发环形模板的 RCA 反应。成功的 RCA 过程导致在微孔板上形成长的 ssDNA 链，这些 ssDNA 链形成了许多用于生物 cDNA 的杂交 DNA 片段。通过 avidin/biotin 在 avi-HRP 和 bio-cDNA 之间的结合，增强了标记的辣根过氧化物酶 (HRP) 的量。在添加 TMB-HO 后，HRP 被催化并产生光学信号。然而，在存在目标的情况下，Hg 特异性地优先与适体结合，形成强而稳定的 T-Hg-T 复合物，导致 cDNA 和 HRP 簇的释放。因此，光学信号降低。我们的结果表明，该系统的检测限 (LOD) 为 1.6 nM，具有优异的特异性，并且在 RCA 条件下的检测信号比没有 RCA 的检测信号增强了 18 倍。该方法已成功用于水样中 Hg 的检测，回收率为 98%-105.74%。
