The Key Lab of Analytical Chemistry for Life Science (MOE), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, PR China.
Talanta. 2011 Apr 15;84(2):531-7. doi: 10.1016/j.talanta.2011.01.060. Epub 2011 Jan 31.
An electrochemical approach for the sensitive detection of sequence-specific DNA has been developed. Horseradish peroxidase (HRP) assembled on the Fe(3)O(4) nanoparticles (NPs) were utilized as signal amplification sources. High-content HRP was adsorbed on the Fe(3)O(4) NPs via layer-by-layer (LbL) technique to prepare HRP-functionalized Fe(3)O(4) NPs. Signal probe and diluting probe were then immobilized on the HRP-functionalized Fe(3)O(4) NPs through the bridge of Au NPs. Thereafter, the resulting DNA-Au-HRP-Fe(3)O(4) (DAHF) bioconjugates were successfully anchored to the gold nanofilm (GNF) modified electrode surface for the construction of sandwich-type electrochemical DNA biosensor. The electrochemical behaviors of the prepared biosensor had been investigated by the cyclic voltammetry (CV), chronoamperometry (i-t), and electrochemical impedance spectroscopy (EIS). Under optimal conditions, the proposed strategy could detect the target DNA down to the level of 0.7 fmol with a dynamic range spanning 4 orders of magnitude and exhibited excellent discrimination to two-base mismatched DNA and non-complementary DNA sequences.
电化学方法用于灵敏检测序列特异性 DNA。辣根过氧化物酶（HRP）组装在四氧化三铁（Fe(3)O(4)）纳米粒子（NPs）上，用作信号放大源。通过层层（LbL）技术将高含量 HRP 吸附在 Fe(3)O(4) NPs 上，制备 HRP 功能化的 Fe(3)O(4) NPs。然后通过 Au NPs 将信号探针和稀释探针固定在 HRP 功能化的 Fe(3)O(4) NPs 上。此后，所得的 DNA-Au-HRP-Fe(3)O(4)（DAHF）生物缀合物成功地锚定在金纳米薄膜（GNF）修饰的电极表面上，用于构建三明治型电化学 DNA 生物传感器。通过循环伏安法（CV）、计时安培法（i-t）和电化学阻抗谱（EIS）研究了制备的生物传感器的电化学行为。在最佳条件下，该策略可检测低至 0.7 fmol 的靶 DNA，检测范围跨越 4 个数量级，并对两个碱基错配 DNA 和非互补 DNA 序列具有出色的区分能力。
