A new chemically amplified electrochemical system for DNA detection in solution

CORC > 生态环境研究中心 > 中国科学院生态环境研究中心 > 环境化学与生态毒理学国家重点实验室

	A new chemically amplified electrochemical system for DNA detection in solution
	Li, C; Liu, SL; Guo, LH; Chen, DP
刊名	ELECTROCHEMISTRY COMMUNICATIONS
	2005
卷号	7 期号:1 页码:23-28
关键词	electrochemical detection chemical amplification DNA intercalation Ru(bpy)(2)dppz
英文摘要	A newly developed chemically amplified electrochemical detection system was applied to the quantitation of DNA in solution. The system employed Ru(bpy)(2)dppz (bpy = 2,2'-bipyridine, dppz = dipyrido[3,2-a :2',3'-c]phenazine), a high-affinity DNA intercalator, as the electrochemical indicator, oxalate as the sacrificial electron donor to chemically amplify the electrochemical signal, and tin-doped indium oxide as the working electrode to suppress background current. Intercalation of Ru(bpy)(2)dppz into calf thymus DNA in solution led to a reduction in the oxalate-amplified electrochemical current as compared to a DNA-free solution. The degree of reduction was a function of the concentration of DNA, thus forming the basis for DNA detection. To illustrate the advantages of the new system, a direct comparison was made between amplified (with oxalate) and non-amplified (without oxalate) DNA detection. In the presence of 100 mM oxalate, anodic current of Ru(bpy)(2)dppz was amplified by more than 60 folds, resulting in substantial improvement in signal-to-background ratio. Furthermore, as the DNA concentration was increased, the amplified current decayed much faster than the non-amplified signal, giving rise to higher detection sensitivity. The steeper decay was attributed to slower redox reaction between DNA-intercalated Ru(bpy)(2)dppz and oxalate, as the negatively charged phosphate groups on DNA repelled the anions. Effect of ionic strength was investigated to provide support for the interpretation. As expected, the decay of the amplified response with increasing concentration of DNA became less steep when more NaCl was added into the solution. The opposite effect was observed when tri-propylamine, a cationic electron donor, was used instead of oxalate. With an optimized concentration of 30 mM oxalate and 5 muM Ru(bpy)(2)dppz, calf thymus DNA of as low as 1 pM was detected in solution, which was close to the detection limit of some fluorescence measurements. (C) 2004 Elsevier B.V. All rights reserved.
学科主题	Electrochemistry
研究领域[WOS]	Electrochemistry
WOS记录号	WOS:000226157600006
内容类型	期刊论文
源URL	[http://ir.rcees.ac.cn/handle/311016/23132]
专题	生态环境研究中心_环境化学与生态毒理学国家重点实验室
推荐引用方式 GB/T 7714	Li, C,Liu, SL,Guo, LH,et al. A new chemically amplified electrochemical system for DNA detection in solution[J]. ELECTROCHEMISTRY COMMUNICATIONS,2005,7(1):23-28.
APA	Li, C,Liu, SL,Guo, LH,&Chen, DP.(2005).A new chemically amplified electrochemical system for DNA detection in solution.ELECTROCHEMISTRY COMMUNICATIONS,7(1),23-28.
MLA	Li, C,et al."A new chemically amplified electrochemical system for DNA detection in solution".ELECTROCHEMISTRY COMMUNICATIONS 7.1(2005):23-28.