State Key Laboratory of Analytical Chemistry for Life Science, Department of Chemistry, Nanjing University, Nanjing 210093, PR China.
Biosens Bioelectron. 2012 Mar 15;33(1):228-32. doi: 10.1016/j.bios.2012.01.006. Epub 2012 Jan 16.
An ultrasensitive electrochemical DNA biosensor was constructed by assembling probe labeled gold nanoparticles (ssDNA-AuNP) on electrochemically reduced graphene oxide (ERGO) modified electrode with thiol group tagged (GT) DNA strand (d(GT)(29)SH) and coupling with horseradish peroxidase (HRP) functionalized carbon sphere (CNS) as tracer. The heteronanostructure formed on the biosensor surface appeared relatively good conductor for accelerating the electron transfer, while the HRP tagged CNS provided dual signal amplification for electrochemical biosensing. The triplex signal amplification strategy produced an ultrasensitive electrochemical detection of DNA down to attomolar level (5 aM) with a linear range of 5 orders of magnitude (from 1 × 10(-17)M to 1 × 10(-13)M), and appeared high selectivity to differentiate single-base mismatched and three-base mismatched sequences of DNA. The proposed approach provided a simple and reliable method for DNA detection with high sensitivity and specificity, indicating promising application in bioanalysis and biomedicine.
构建了一种超灵敏的电化学 DNA 生物传感器，该传感器通过将巯基标记的（GT）DNA 链（d(GT)(29)SH）组装到带有硫醇基团的电化学还原氧化石墨烯（ERGO）修饰电极上，再与辣根过氧化物酶（HRP）功能化碳球（CNS）结合作为示踪剂，从而在生物传感器表面形成异质纳米结构。该异质纳米结构作为相对较好的导体，可加速电子转移，而标记 HRP 的 CNS 则为电化学生物传感提供了双重信号放大。三链信号放大策略实现了对 DNA 的超灵敏电化学检测，检测下限低至飞摩尔级（5 aM），线性范围为 5 个数量级（从 1×10(-17)M 至 1×10(-13)M），并对单碱基错配和三碱基错配的 DNA 序列具有高选择性。该方法为高灵敏度和特异性的 DNA 检测提供了一种简单可靠的方法，有望在生物分析和生物医学领域得到应用。
