Ferapontova Elena E, Olsen Eva M, Gothelf Kurt V
Danish National Research Foundation: Centre for DNA Nanotechnology (CDNA), Department of Chemistry and iNANO, The Faculty of Science, Aarhus University, Langelandsgade 140, DK-8000 Aarhus C, Denmark.
J Am Chem Soc. 2008 Apr 2;130(13):4256-8. doi: 10.1021/ja711326b. Epub 2008 Mar 7.
An electrochemical RNA aptamer-based biosensor for rapid and label-free detection of the bronchodilator theophylline was developed. The 5'-disulfide-functionalized end of the RNA aptamer sequence was immobilized on a gold electrode, and the 3'-amino-functionalized end was conjugated with a ferrocene (Fc) redox probe. Upon binding of theophylline the aptamer switches conformation from an open unfolded state to a closed hairpin-type conformation, resulting in the increased electron-transfer efficiency between Fc and the electrode. The electrochemical response, which was measured by differential pulse voltammetry, reaches saturation within a few minutes after addition of theophylline, and the dynamic range for detecting theophylline is 0.2-10 muM. The electrode displays an inhibited response when applied directly in serum samples treated with RNase inhibitors; however a full response to the theophylline serum concentration was obtained by transferring the electrode to blank serum-free buffer solutions. It was demonstrated that theophylline is detected with high selectivity in the presence of caffeine and theobromine.
开发了一种基于电化学RNA适配体的生物传感器，用于快速、无标记检测支气管扩张剂茶碱。RNA适配体序列的5'-二硫键功能化末端固定在金电极上，3'-氨基功能化末端与二茂铁（Fc）氧化还原探针共轭。茶碱结合后，适配体从开放的未折叠状态转变为封闭的发夹型构象，导致Fc与电极之间的电子转移效率增加。通过差分脉冲伏安法测量的电化学响应在加入茶碱后几分钟内达到饱和，检测茶碱的动态范围为0.2-10μM。当直接应用于用RNase抑制剂处理的血清样品时，电极显示出抑制响应；然而，通过将电极转移到无血清空白缓冲溶液中，获得了对茶碱血清浓度的完全响应。结果表明，在咖啡因和可可碱存在的情况下，茶碱能够被高选择性地检测。
