Department of Chemistry, Graduate School of Science, Tohoku University, Aoba-ku, Sendai 980-8578, Japan.
Anal Chim Acta. 2010 Aug 18;675(1):49-52. doi: 10.1016/j.aca.2010.06.042.
By using iodide (I(-)) as a quencher, we successfully improve the fluorescence response of amiloride when binding to thymine opposite an AP site in a 21-meric DNA duplex. From fluorescence measurements, as compared to the NaCl solutions, the addition of NaI as a quencher as well as salt to adjust the ionic strength effectively suppresses the background fluorescence from unbound amiloride in a solution. The Stern-Volmer analysis shows that the bound amiloride to the nucleobase at the AP site is unexposed to NaI quencher. Therefore the high signal-to-background fluorescence response of amiloride is obtained. Such enhancement in fluorescence response of amiloride by using the quencher can provide the significant improvement of the detection limit for DNA duplexes carrying T target base. The method presented in this study is simple and effective. The present method could be applicable to other detection system where microenvironment of fluorophores changes at a recognition event.
通过使用碘化物 (I(-)) 作为猝灭剂，我们成功地提高了阿米洛利与胸腺嘧啶在 21 个碱基对 DNA 双链体中与 AP 位点结合时的荧光响应。通过荧光测量，与 NaCl 溶液相比，添加 NaI 作为猝灭剂以及盐来调节离子强度可有效抑制溶液中未结合的阿米洛利的背景荧光。Stern-Volmer 分析表明，结合到 AP 位点上的核碱基的阿米洛利不易受到 NaI 猝灭剂的影响。因此，阿米洛利获得了高的信号背景荧光响应。通过使用猝灭剂增强阿米洛利的荧光响应，可以显著提高携带 T 靶碱基的 DNA 双链体的检测限。本研究中提出的方法简单有效。本方法可适用于其他荧光团微环境在识别事件中发生变化的检测系统。
