第32卷第2期 2012年6月
化学传感器 CHEMICALSENSORS
单壁碳纳米管的猝灭效应用于银离子的检测
丁静，王青，羊小海，王柯敏，黄佳浩，刘沛
Vol. 32, No. 2 June .2 012
（湖南大学化学生物传感与计量学国家重点实验室，化学化工学院，生物纳米与分子工程湖南省重点实验
室，湖南长沙410082）
摘要：基于单壁碳纳米管(SWNTs)良好的猝灭性能，发展了利用单链DNA(ssDNA)和单壁碳纳米管的荧光探针用于对Ag进行检测的方法。其中富含C碱基的FAM标记的单链DNA（ssDNA)与单壁碳纳米管(SWNTs)发生*π间的相互作用后，其荧光被猝灭。当有Ag*加人时，ssDNA会由于C-Ag*-C作用形成发夹结构，刚性增强从而脱离碳纳米管使荧光信号较好的恢复，据此可检测Ag*。该方法简便，避免了ssDNA
水样中的检测，
关键调：单壁碳纳米管；Ag；单链DNA
Detection of silverionusingfluorescencequenchingof singlewalled
carbon nanotubes
Ding Jing, Wang Qing, Yang Xiao-hai, Wang Ke-min', Huang Jia-hao, Liu Pei
(State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering. Key Laboratory for BioNanotechnology and Molecular Engineering of Hunan Province, Hunan University
Changsha 410082, China)
Abstract: A simple fluorescence assay has been developed for detection of silver ion based on the fluorescence quenching of singlewalled earbon nanotubes (SWNTs) and the specifically binding ability of cytosine cytosine (C C) and Ag*. Single walled carbon nanotubes (SWNTs) can effectively quench the fluorescence of FAMlabeled single stranded Crich DNA due to their strong t*r stacking interactions. In the presence of silver ion, single-stranded Crich DNA can form hair structure since silver ion (Ag') can specifically bind to the cytosine cytosine (C C) base pair, and SWNTs was detached form DNA, so the fluorescence signal enhanced subsequently. Detection of silver ion can be achieved according to the change of fluorescence signal. This method only needs one step mixing
with a detection limit of O.6 nmol/L, and could be applied to Agt detection in real sample Key words: single walled carbon nanotubes; silver ion; singlestranded DNA
吸收法(ETAAS)[5~6]、电感耦合等离子体发射光
引言 0
银广泛存在于自然界中。它可作为金属催化剂、抗菌剂、感光剂等。相比其他形式的银，离子形式的银是毒性最大的]。Ag在水中易被生物富集[2~3]，进而抑制蛋白的活性，间接地影响生物的繁衍[4]。因此发展快速、简便的Ag检测方法是有意义的。目前，Ag的检测方法很多，如电热原子
*通讯联系人
谱法（ICP-AES)[7]、电感耦合等离子体质谱法(ICP-MS)[8~9]。这些方法灵敏度较高，但是都需要昂贵的仪器，成本较高。
已有报道[10~1]富含胞嘧啶(C)的DNA能与 Ag特异性结合，利用这一性质，发展了一系列检测Ag*的方法。如Ono等[12]在富含C的DNA探针两端分别标记荧光基团和猝灭基团，当存在