PNA-based DNA assay with attomolar detection limit based on polygalacturonic acid mediated in-situ deposition of metallic silver on a gold electrode
PNA-based DNA assay with attomolar detection limit based on polygalacturonic acid mediated in-situ deposition of metallic silver on a gold electrode
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基于聚半乳糖醛酸介导的金电极上金属银原位沉积的具有阿托摩尔检测限的基于 PNA 的 DNA 测定
DOI：
10.1007/s00604-014-1351-1
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发表时间：
2015-01-01
影响因子：
5.7
通讯作者：
Zhang, Xueji
中科院分区：
文献类型：
--
作者：
Hu, Qiong;Hu, Weiwen;Zhang, Xueji
描述了一种通过使用多糖介导的金属银在金电极上原位沉积来超灵敏地测定序列特异性DNA的电化学方法。具体地，通过形成自组装单层将硫醇化肽核酸（PNA）固定在金电极上。在PNA和靶单链DNA（ssDNA）之间的杂交之后，多聚半乳糖醛酸（PGUA）通过磷酸-锆-羧酸配位相互作用被引入到PNA/DNA异源双链体。接下来，多糖骨架的邻位羟基被裂解并氧化成醛基。它们充当还原剂，将添加的银离子转化为原位沉积在金电极上的金属银，然后电化学剥离到KCl溶液中，在此通过差分脉冲伏安法准确测定。在最佳条件下，该测定法表现出宽的线性响应范围，因为溶出电流与靶ssDNA浓度的对数在0.1 fM至10 pM范围内相关，检测限低至2.5 aM。该方法在清楚区分错配寡核苷酸片段方面显示出优异的特异性。因此，我们认为，这种方法在单核苷酸多态性基因分型方面具有很大的潜力。此外，这种信号放大具有非常大的能力，相对于超灵敏定量的低丰度biologicals.Graphical AbstractThe超灵敏测定序列特异性DNA的电化学方法与attomolar检测限的基础上，利用多糖作为信号放大介体对原位金属化首次提出。该方法不仅具有良好的特异性和重复性，而且对血清样品的分析能力也很好，因此在临床诊断中用于真实的样品检测方面具有很大的潜力。
An electrochemical method is described for the ultrasensitive determination of sequence-specific DNA by using polysaccharide-mediated in-situ deposition of metallic silver on a gold electrode. Specifically, a thiolated peptide nucleic acid (PNA) is immobilized on the gold electrode via formation of a self-assembled monolayer. Following hybridization between PNA and target single-stranded DNA (ssDNA), polygalacturonic acid (PGUA) is introduced to the PNA/DNA heteroduplexes via phosphate-zirconium-carboxylate coordination interaction. Next, the vicinal hydroxy groups of the polysaccharide backbone are cleaved and oxidized into aldehyde groups. These act as reductants and convert added silver ions into metallic silver which in-situ deposits on the gold electrode, and then is stripped off electrochemically into a solution of KCl where it is accurately determined by differential pulse voltammetry. Under optimal conditions, this assay exhibits a wide linear response range in that the stripping current is related to the logarithm of the concentration of target ssDNA in the 0.1 fM to 10 pM range, with a detection limit as low as 2.5 aM. The method displays excellent specificity in clearly differentiating mismatched oligonucleotide fragments. We therefore believe that this method has a large potential in terms of genotyping of single-nucleotide polymorphism. Moreover, this kind of signal amplification possesses a very large capability with respect to ultrasensitive quantitation of low-abundant biomarkers.Graphical AbstractThe electrochemical method for the ultrasensitive determination of sequence-specific DNA with attomolar detection limit based on exploiting polysaccharide as signal amplification mediator toward in-situ metallization is firstly presented. Apart from its excellent specificity and repeatability, it also exhibits acceptable analytical capability in serum samples, and therefore shows great potential to be employed for real sample detection in clinical diagnostic.