Loading/release behavior of (chitosan/DNA)n layer-by-layer films toward negatively charged anthraquinone and its application in electrochemical detection of natural DNA damage.
Loading/release behavior of (chitosan/DNA)n layer-by-layer films toward negatively charged anthraquinone and its application in electrochemical detection of natural DNA damage.
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DOI：
10.1016/j.bios.2007.07.009
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发表时间：
2007-12
影响因子：
12.6
通讯作者：
Yi Liu;N. Hu
中科院分区：
文献类型：
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作者：
Yi Liu;N. Hu
在本研究中，带正电荷的壳聚糖（CS）和带负电荷的DNA交替吸附在热解石墨（PG）电极表面，形成（CS/DNA）层层薄膜。循环伏安法（CV）结果表明，带负电荷的电活性探针9,10-蒽醌-2,6-二磺酸盐（AQDS）可从其溶液（pH 7.0，含0.1M NaCl, 1mM）中加载到（CS/DNA） n-AQDS中，并将其释放到空白缓冲液中。发现（CS/DNA）膜对AQDS的加载/释放行为在双链DNA （dsDNA）和单链DNA （ssDNA）之间存在明显差异。（CS/dsDNA） n膜中AQDS的释放速度比ssDNA的释放速度慢得多，这主要是因为AQDS可以嵌入dsDNA的双螺旋结构中，尽管可能带电荷的AQDS与DNA之间存在排斥力。利用（CS/DNA）膜对AQDS的加载/释放行为识别dsDNA和ssDNA，成功地应用于电化学检测芬顿反应对天然DNA的损伤。为了进一步了解（CS/DNA）膜中AQDS加载/释放过程中相互作用的本质，我们进行了对比实验，用带正电荷的插层剂亮甲酰蓝（BCB）代替AQDS作为氧化还原探针，或用正电荷密度较高的聚二烯基二甲基铵（PDDA）代替CS作为DNA层膜的组成部分。DNA膜对电活性插层的加载/释放行为为dsDNA/ssDNA识别和电化学检测DNA损伤开辟了新的可能性。
In the present work, positively charged chitosan (CS) and negatively charged DNA were alternately adsorbed on the surface of pyrolytic graphite (PG) electrodes, forming (CS/DNA)nlayer-by-layer films. Cyclic voltammetry (CV) results showed that negatively charged electroactive probe, 9,10-anthraquinone-2,6-disulfonate (AQDS), could be loaded into the (CS/DNA)nfilms from its solution (1mM at pH 7.0, containing 0.1M NaCl), designated as (CS/DNA)n–AQDS, and then released from the films in blank buffers. The loading/release behavior of (CS/DNA)nfilms toward AQDS was found to be obviously different between double-stranded (dsDNA) and single-stranded DNA (ssDNA). The release rate of AQDS from (CS/dsDNA)nfilms was much slower than that from the ssDNA counterparts mainly because AQDS could be intercalated into the double helix structure of dsDNA despite the repulsion between likely charged AQDS and DNA. The loading/release behavior of (CS/DNA)nfilms toward AQDS in recognition of dsDNA and ssDNA was then successfully applied to electrochemically detect the damage of natural DNA caused by Fenton reaction. To further understand the essence of the interactions involved in the AQDS loading/release process for (CS/DNA)nfilms, comparison experiments were performed, in which either positively charged intercalator brilliant cresyl blue (BCB) was used to replace AQDS as the redox probe, or poly(diallyldimethylammonium) (PDDA) with relatively high positive charge density was used to replace CS as the constituent of layer-by-layer films with DNA. The loading/release behavior of DNA films toward electroactive intercalator may open new possibilities for dsDNA/ssDNA recognition and of DNA damage detection by electrochemistry.