The Key Laboratory of Food Colloids and Biotechnology, Ministry of Education, School of Chemical and Material Engineering, Jiangnan University, Wuxi 214122, PR China.
The Key Laboratory of Food Colloids and Biotechnology, Ministry of Education, School of Chemical and Material Engineering, Jiangnan University, Wuxi 214122, PR China.
Anal Chim Acta. 2015 Apr 29;871:1-8. doi: 10.1016/j.aca.2015.02.027. Epub 2015 Feb 13.
In this paper, a novel colorimetric biosensor for Hg(2+) and DNA molecules is presented based on Hg(2+) stimulated oxidase-like activity of bovine serum albumin protected silver clusters (BSA-Ag NCs). Under mild conditions, Hg(2+) activated BSA-Ag NCs to show high catalytic activity toward the oxidation of 3,3',5, 5'-tetramethylbenzidine (TMB) using ambient dissolved oxygen as an oxidant. The oxidase-like activity of BSA-Ag NCs was "switched-on" selectively in the presence of Hg(2+), which permitted a novel and facile colorimetric sensor for Hg(2+). As low as 25 nmol L(-1)Hg(2+) could be detected with a linear range from 80 nmol L(-1) to 50 mmol L(-1). In addition, the sensing strategy was also employed to detect DNA molecules. Hg(2+) is known to bind very strongly and specifically with two DNA thymine bases (T) to form thymine-Hg(2+)-thymine (T-Hg(2+)-T) base pairs. The hairpin-structure was disrupted and Hg(2+) ions were released after hybridization with the DNA target. By coupling the Hg(2+) switched-on the oxidase-mimicking activity of BSA-Ag NCs, we developed a novel label-free strategy for facile and fast colorimetric detection of DNA molecules. More important, target DNA can be detected as low as 10 nmol L(-1) with a linear range from 30 to 225 nmol L(-1). Compared with other methods, this method presents several advantages such as the independence of hydrogen peroxide, high sensitivity and good selectivity, avoiding any modification or immobilization of DNA, which holds a great potential of metal NCs for clinical application in biosensing and biotechnology.
本文提出了一种基于牛血清白蛋白保护的银纳米簇（BSA-Ag NCs）的 Hg(2+) 刺激的过氧化物酶样活性的新型比色生物传感器，用于检测 Hg(2+) 和 DNA 分子。在温和的条件下，Hg(2+) 激活 BSA-Ag NCs，使其在环境溶解氧的存在下对 3,3',5,5'-四甲基联苯胺（TMB）的氧化具有高催化活性。BSA-Ag NCs 的过氧化物酶样活性在 Hg(2+) 的存在下被“开启”，这使得新型的、简便的 Hg(2+) 比色传感器成为可能。检测 Hg(2+) 的线性范围为 80 nmol L(-1) 至 50 mmol L(-1)，检出限低至 25 nmol L(-1)。此外，该传感策略还可用于检测 DNA 分子。已知 Hg(2+) 能够与两个 DNA 胸腺嘧啶碱基（T）非常强且特异性地结合，形成胸腺嘧啶-Hg(2+)-胸腺嘧啶（T-Hg(2+)-T）碱基对。发夹结构被破坏，并且在与 DNA 靶标杂交后释放出 Hg(2+) 离子。通过耦合 Hg(2+) 开启 BSA-Ag NCs 的过氧化物酶模拟活性，我们开发了一种简便快速的比色检测 DNA 分子的新型无标记策略。更重要的是，该方法可检测低至 10 nmol L(-1) 的靶 DNA，线性范围为 30 至 225 nmol L(-1)。与其他方法相比，该方法具有许多优势，如不依赖于过氧化氢、高灵敏度和良好的选择性，避免了 DNA 的任何修饰或固定化，这为金属 NCs 在生物传感和生物技术中的临床应用提供了巨大的潜力。
