A dual signal amplification strategy combining thermally initiated SI-RAFT polymerization and DNA-templated silver nanoparticles for electrochemical determination of DNA
A dual signal amplification strategy combining thermally initiated SI-RAFT polymerization and DNA-templated silver nanoparticles for electrochemical determination of DNA
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结合热引发 SI-RAFT 聚合和 DNA 模板银纳米粒子的双信号放大策略，用于 DNA 的电化学测定
DOI：
10.1007/s00604-019-3912-9
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发表时间：
2020-01-01
影响因子：
5.7
通讯作者：
Zhang, Xueji
中科院分区：
文献类型：
--
作者：
Liu, Bang;Sun, Haobo;Zhang, Xueji
本文介绍了一种高灵敏度的DNA测定方法。它基于双重信号放大，即（a）DNA模板金属沉积，和（B）热引发的表面引发可逆加成-断裂链转移（SI-RAFT）聚合。通过自组装将末端带有巯基的肽核酸（PNA）固定在金电极上。修饰电极作为探针选择性地捕获靶DNA（tDNA）。在下一步中，Zr（IV）离子与tDNA的磷酸基团结合。用于热引发SI-RAFT聚合的链转移剂（CTA）4-氰基-4-（苯基硫代碳酰硫基）戊酸（CPAD）通过羧基与Zr（IV）离子的缀合固定在tDNA上。随后，甲基丙烯酸糖基氧基乙酯（GEMA）的许多单体连接到CPAD通过热引发的SI-RAFT聚合与偶氮二异丁腈（AIBN）作为自由基热引发剂。然后，通过高碘酸钠氧化GEMA中的羟基为醛基，通过“银镜反应”将银纳米粒子引入到电极表面。这导致大的电化学信号放大。在优化的条件下，电化学信号（最好在0 V vs. SCE（KCl; 3 M）的工作电位下测量）在10至106 aM的浓度范围内随tDNA浓度的对数线性增加。检测限低至5.6 aM（类似于10 μ L样品中的34个分子）。这比大多数其他超灵敏电化学DNA测定的检测限低2至1800倍。
A highly sensitive method is described for determination of DNA. It is based on dual signal amplification, viz. (a)DNA-templated metal deposition, and (b) thermally initiated surface-initiated reversible addition-fragmentation chain transfer (SI-RAFT) polymerization. A peptide nucleic acid (PNA) with a terminal thiol group was grasped onto a gold electrode by self-assembly. The modified electrode serves as a probe to selectively capture target DNA (tDNA). In the next step, Zr(IV) ions are bound to the phosphate groups of the tDNA. A chain-transfer agent (CTA) for thermally initiated SI-RAFT polymerization, 4-cyano-4-(phenylcarbonothioylthio)pentanoic acid (CPAD), was immobilized on tDNA by conjugation of the carboxy group to Zr(IV) ions. Subsequently, numerous monomers of glycosyloxyethyl methacrylate (GEMA) were connected to the CPAD by thermally initiated SI-RAFT polymerization with azobisisobutyronitrile (AIBN) serving as the free-radical thermal initiator. Afterwards, hydroxyl groups of the GEMA were oxidized to aldehyde groups reacting with sodium periodate, and silver nanoparticles were further introduced on the surface of electrode via "silver mirror reaction". This results in a large electrochemical signal amplification. Under optimized conditions, the electrochemical signal (best measured at aworking potential of 0V vs. SCE (KCl; 3 M)) increases linearly with the logarithm of tDNA concentration in the 10 to 106 aM concentration range. The detection limit is as low as 5.6 aM (similar to 34 molecules in a 10 mu L sample). This is lower by factors between 2 and 1800 times than detection limits of most other ultra-sensitive electrochemical DNA assays.