Ultrasensitive electrochemical DNA biosensor by exploiting hematin as efficient biomimetic catalyst toward in situ metallization.
Ultrasensitive electrochemical DNA biosensor by exploiting hematin as efficient biomimetic catalyst toward in situ metallization.
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DOI：
10.1016/j.bios.2014.07.034
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发表时间：
2015-01
影响因子：
12.6
通讯作者：
Qiong Hu;Weiwen Hu;J. Kong;Xueji Zhang
中科院分区：
文献类型：
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作者：
Qiong Hu;Weiwen Hu;J. Kong;Xueji Zhang
本论文提出了一种新的信号放大方法，利用血红素作为仿生催化剂，构建了一种用于序列特异性DNA超灵敏测定的电化学DNA生物传感器。首先将巯基化肽核酸（thiolated peptide nucleic acid，PNA）探针通过自组装膜（self-assembled monolayer，SAM）的形成固定在金电极上，然后进行杂交。在此之后，血红素分子被引入到杂交PNA/DNA异源双链体通过使用磷酸锆羧酸配位化学。接着，在邻苯二酚存在下，血红素分子作为催化剂加速了银离子的还原，导致银粒子原位沉积在电极上。最后，沉积的银颗粒被电化学剥离到KCl溶液中，并通过方波伏安法（SWV）进行测量。在最佳条件下，该电化学DNA生物传感器的溶出峰电流与单链DNA（ssDNA）浓度的对数在0.1 ~ 0.1 nM范围内呈良好的线性关系，检出限为62.41 aM，对血清样品中ssDNA的测定具有良好的分析性能。该方法具有良好的重复性和稳定性，同时对单核苷酸多态性（SNP）也具有良好的特异性。因此，基于血红素的信号放大方法具有巨大的临床应用潜力，也适用于超低水平的生物标志物定量。
In this work, we presented a novel signal amplification approach to construct an electrochemical DNA biosensor for the ultrasensitive determination of sequence-specific DNA by exploiting hematin as biomimetic catalyst towardin situmetallization. Briefly, thiolated peptide nucleic acid (PNA) probes were firstly immobilized onto gold electrode through the formation of self-assembled monolayer (SAM) and then hybridization was accomplished in the ensuing step. After that, hematin molecules were introduced to the hybridized PNA/DNA heteroduplexes by employing phosphate–zirconium–carboxylate coordination chemistry. Next, the attached hematin molecules acted as catalyst in accelerating the reduction of silver ions in the presence of catechol, leading to thein situdeposition of silver particles onto the electrode. Finally, the deposited silver particles were electrochemically stripped into KCl solution and measured by square wave voltammetry (SWV). Under optimal conditions, the hematin-based electrochemical DNA biosensor presented a good linear relationship between the stripping peak currents and logarithm of single-stranded DNA (ssDNA) concentrations in the range from 0.1 fM to 0.1 nM with a low detection limit of 62.41 aM, and it rendered satisfactory analytical performance for the determination of ssDNA in serum samples. Furthermore, it exhibited good reproducibility and stability, meanwhile, it also showed excellent specificity toward single-nucleotide polymorphism (SNP). Therefore, the hematin-based signal amplification approach has great potential in clinical applications and is also suitable for quantification of biomarkers at ultralow level.